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| author | luxagraf <sng@luxagraf.net> | 2023-03-03 09:27:18 -0600 |
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| committer | luxagraf <sng@luxagraf.net> | 2023-03-03 09:27:18 -0600 |
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diff --git a/bookmarks/the super cat alcohol stove.txt b/bookmarks/the super cat alcohol stove.txt deleted file mode 100644 index bbff20a..0000000 --- a/bookmarks/the super cat alcohol stove.txt +++ /dev/null @@ -1,2810 +0,0 @@ ---- -title: The Super Cat Alcohol Stove -date: 2015-11-30T14:30:41Z -source: http://jwbasecamp.com/Articles/SuperCat/ -tags: backpacking, camping, projects - ---- - -A simple-to-make, hot-burning, backcountry stove - -The Super Cat Alcohol Stove - -[4]By Jim Wood - -Originally published January 29, 2005 -Major update November 18, 2008 - -Last revised March 4, 2011 - -[5]Printable PDF version available here (1.0mb) - -[6]Submit or read comments about this article here - __________________________________________________________________ - -Originally developed in early 2004, the Super Cat alcohol stove was -first shared with the online backpacking community in January, 2005. -Since then, it's become one of the most popular do-it-yourself alcohol -stoves among hikers worldwide for probably two reasons: it works -exceptionally well and it's very easy to make. - -This update to the [7]original article is intended to incorporate many -of the design ideas that Super Cat users have contributed over the -years, as well as to expand the scope to include new information about -build techniques, fuels, windscreens, stands and other accessories. - -It's also being published concurrently with a new article entitled -"[8]The Fire Bucket Stove System", which introduces a companion product -that can serve either as a high performance windscreen for the Super -Cat (and most other alcohol heaters), or a stand-alone stove that is -capable of burning wood and solid fuel tablets--all at a weight (in its -lightest implementations) of about two ounces. - -When used together, the Super Cat and Fire Bucket form an efficient, -lightweight, integrated stove system that's easy to make and fun to -operate. - -You can navigate directly to each chapter using the links below. - - [9]Background - - [10]Alcohol Stove Designs - - [11]Disclaimers and Safety Notes - - [12]Materials - - [13]Tools - - [14]Super Cat Build Instructions - - [15]Super Cat Fuels - - [16]Starting and Using the Stove - - [17]Accessories - - [18]Resources - - __________________________________________________________________ - -Background - __________________________________________________________________ - -More than a century after the venerable Svea kerosene stove first went -into production, one might reasonably wonder why backcountry stoves, -like so many other mature products, haven't coalesced around one or two -successful design technologies. - -Instead, today's backpackers still burn white gas, kerosene, diesel, -automotive gas, jet fuel, propane, solid fuel tablets, butane/propane -mixes, wood, paraffin, mineral spirits, vegetable oils, methanol, -ethanol, and isopropyl alcohol in a huge variety of stove types. - -So why still so many choices? I guess simply because no one has yet -been able to come up with an all-in-one design that can meet the wide -range of environmental, fuel availability, weight, cooking, and safety -requirements of today's hikers. - -The future may belong to an atomic fusion stove that weighs two ounces -and can run for a hundred years on one gram of fuel, but in the -meantime, the top-mounted (iso)butane/propane canister stove probably -comes closest to meeting the needs of most of today's three-season -backpackers, particularly those who trek in Europe and North America. - -Ultralight models, often equipped with piezoelectric lighters, are made -by MSR, Primus, Gaz, Snow Peak, Brunton, Optimus, Coleman and others, -and are convenient, dependable, quiet, efficient, and though hot -burning, can also simmer well. In addition, analysis has shown that -even for gram-counting long-distance hikers, these stoves compare -favorably with other types of stoves from a weight-to-performance point -of view. - -Nonetheless, these stoves are not perfect. My own biggest complaint is -that the fuel canisters themselves are not refillable by the user, -which means that it's often difficult carry just the amount of fuel -that you think you'll need for a given outing. - -In addition, compatible canisters are sometimes difficult to find -outside the U.S. or when re-supplying on long hikes (canisters can't be -transported on commercial airliners). These stoves also typically -perform poorly in cold weather and can be difficult to use with -conventional windscreens (although the [19]KiteScreen offers a great -solution to this last problem). - -Alcohol Stoves - -Alcohol stoves are one of the most popular alternatives to canister -stoves, especially for long-distance hikers, perhaps because they solve -one key problem: fuel availability. Alcohol stoves can burn ethanol or -methanol (and combinations thereof), or in a pinch, even isopropyl -alcohol, which means that fuels at re-supply points are generally -fairly easy to find at liquor, hardware, automotive or variety stores. - -Alcohol stoves also allow hikers to carry just the amount of fuel -needed for a given outing, are super-quiet in operation, are usually -very simple in design (no fuel jets to clog or other components to fail -in the field), and are usually extremely light weight. Many -green-spirited backpackers also like alcohol stoves because they use a -renewable fuel source, unlike the majority of stoves now in use that -burn fossil fuels (although alcohol stoves still emit carbon dioxide, -a greenhouse gas). - -On the flip side, alcohol stoves present certain safety hazards, -including a flame that's nearly invisible in sunlight (which means that -it's sometimes difficult to detect when the stove is operating) and the -use of an open fuel tank that can spill flaming alcohol on you and your -surroundings if tipped over. - -These stoves are typically also more wind-sensitive than other -types--and as a double whammy--use their fuel much more quickly than do -fuel-metered stoves under windy conditions, at least if not properly -protected. And while they excel at boiling water, alcohol stoves are -typically difficult to control for simmering. - -All designs of which I'm aware must be also re-filled after every use. -This single-shot-of-fuel per use operation means that it's often tricky -to gage how much alcohol to add to your stove for any given cooking -operation. As a result, backcountry cooks usually either run out of -fuel before finishing, or end up with excess fuel that frequently burns -wastefully away until it's finally consumed (although some of the -accessories and techniques described below can reduce this waste). - -Likewise, the energy content of alcohol is considerably less than -comparable petroleum-based fuels (typically about half), which means -that significantly more fuel must be carried. The good news here is -that alcohol fuels are safer to handle, can be transported in ordinary -plastic bottles, and can be extinguished with water in an emergency. - -JIM'S STRATEGY - -Despite their disadvantages, I still like alcohol stoves. Sometimes I -use one as a primary heater and sometimes as a backup or "fill-in" for -my canister stove. Carrying an alcohol stove, which weighs almost -nothing by itself, often allows me to avoid carrying a second weighty -canister if I'm concerned about not having quite enough fuel. I can -include just the right amount of alcohol to supplement the main -butane/propane supply for the trip. - -For this type of use, a backup stove doesn't need to be a full-featured -replacement. All it really needs to do well is boil water in a -reasonable amount of time, which also allows it serve as a second -burner in the preparation of some meals. - -I also now usually carry the Fire Bucket Stove System which can work as -a windscreen for either the Super Cat or canister stove (see the -[20]Fire Bucket article for details), or in a pinch, burn wood if I run -out of other types of fuel. - __________________________________________________________________ - -Alcohol Stove Designs - __________________________________________________________________ - -There are dozens of do-it-yourself alcohol stoves currently described -in various spots around the Internet. Rather than duplicate information -that's already available, I would instead refer you to the most -complete backpacking stove site that I've found thus far: the [21]Zen -Stove site. - -NON-PRESSURIZED vs PRESSURIZED - -For purposes of classification, however, I will note that alcohol stove -designs generally fall into one of two categories: non-pressurized and -pressurized. - -Non-pressurized models work by simply housing an open flame that's -created by burning expanding alcohol gases. These gases exist anytime -that liquid alcohol is warm enough to evaporate, where the warmer the -liquid, the faster the rate of evaporation. Examples include Roy -Robinson's Cat Stove and the Robert Crowley Plumber Stove. - -Pressurized models restrict the expansion of this gas in some manner to -create gas "jets" that are said to burn a little hotter than do -non-pressurized flames. Since I've done limited testing myself, I can't -say for sure that it really makes any difference, but in either case, -the Super Cat would be classified as a pressurized design. Also, -because of slightly higher flame velocities, pressurized models are -probably tend to be a bit less wind-sensitive. - -While I'm at it, I'll also note that the term "pressurized" may also be -a bit overstated, since the amount of back-pressure created by -restricting the gas flow is very small--just enough, in fact, to force -the expanding gas out through a series of burner holes. It's nothing -like the pressure, for example, that's created by manually pumping an -MSR white gas fuel bottle. - -SIMPLICITY OF DESIGN - -Probably the most significant thing that sets the Super Cat apart from -other pressurized stoves such as Scott Henderson's Pepsi-G, the -Anti-Gravity Gear Tin Man, or the Brasslite stoves, is the simplicity -of design. - -Most pressurized stoves require multiple components that must be taped, -epoxied, or welded together in order to create their pressure chambers. -The Super Cat's pressure chamber, on the other hand, is created simply -by placing a pot on top of the stove, thereby blocking the ability of -the expanding gas to escape through the top, forcing the flames out -through the side vents. - -The Super Cat design is also simpler than most others because it -doesn't require the use of a separate pot stand. The stove itself -serves as both the burner element and the stand, since the pot is -placed directly over the top of the stove. - -Because of its uncomplicated design, the Super Cat is also very easy to -build. So easy, in fact, that they're sometimes constructed on the -trail (often in less than five minutes) using materials procured at -re-supply stops. - -Incidentally, I should note that this stove is named "Super" because it -burns hotter and faster than most other alcohol stoves whose -specifications I've seen. With some implementations of the Super Cat, -I've consistently (under ideal, no-wind conditions) brought two cups of -water from cool room temperature to a full rolling boil in under four -minutes, which is among the fastest times I've noted so far, though -there's really no way to guarantee the consistency of the conditions -among all those who conduct these tests. - -It's also called "Super" since it's super-easy to make and, at a weight -of less than ¼ of an ounce, super-light weight. The "Cat" portion of -the name was derived from its construction using a single, 3 ounce -aluminum cat food can. - -WHY THE SUPER CAT WORKS - -Unfortunately, one can't punch a few holes in any old can and expect to -turn it into a working pressurized stove. For starters, the can's -volume needs to be just right for the alcohol vapors to pressurize in a -way that allows them to expand through the side vent holes after -lighting. - -If the internal space is too large, the flame will simply be -extinguished when the pot is lowered into place. Alternatively, if it's -too small, the same thing will probably happen, but even if it manages -to pressurize, the stove's fuel capacity will likely be too low to -complete most cooking operations without refilling. - -The diameter of the can is also important since the stove also serves -as the pot stand. If the diameter is too small, the stove could become -unstable when a pot is placed upon it. If the stove is too wide, the -flames will probably miss most of the pot's bottom surface and some of -the heat will be lost up the sides (though there are some interesting -exceptions to the conventional wisdom regarding stove and pot width -that are discussed below). - -The material and thickness of the can's walls are also critical. In -order for the stove to work properly, some of its heat must be -transferred back into the open pool of alcohol to keep it boiling -("thermal feedback"). If the the stove is made from a metal that's -either too thick or that conducts heat poorly, the alcohol can stop -boiling, killing the flame. - -Conversely, if the sidewalls are too thin, then the stove probably -won't support the weight of a pot filled with two to four cups of water -(which might weigh two pounds or more) and could collapse when heated -to operating temperature. - -SO HERE'S THE MAGIC - -It turns out that the 3 ounce aluminum can that's recommended for Super -Cat use is just about perfect for this task. - -The volume is such that the alcohol vapors pressurize properly under -almost all altitude, temperature and other operating conditions. It's -also large enough that, depending on hole configuration, it will hold -up to 2 fluid ounces of fuel, which is usually more than enough for -most cooking chores. Likewise, the can's diameter easily supports most -commonly used pot sizes while maintaining a high degree of efficiency. - -The aluminum walls are likewise thin enough to efficiently conduct heat -to the alcohol pool to keep it boiling, but are also thick enough to -safely support the weight of a full pot of water (at least of the size -range most likely to be used). - -Over the years, I've experimented a variety of other cans types that -have been larger, smaller, and constructed from metals such as steel -and brass, and I have yet to find anything that works as well as the -3 ounce aluminum can. - -the question of pot width - -One interesting thing I've learned from my development experiences is -that the conventional wisdom about side-burner stoves and pot width is -not necessarily correct. Many hikers believe that alcohol stoves like -the Super Cat only work well with wide-bottom pots under the theory -that narrow pots allow too much of the stove's heat to flow up the -sides of the vessel, thereby significantly reducing efficiency. In -truth, it's not that simple. - -Somewhat to my amazement, the fastest boil times I've ever observed -with the Super Cat have been with tall, narrow cook pots. More -specifically, I'm referring to those that are constructed from 24 or 25 -ounce aluminum beer cans sold by Heineken, Fosters and others. These -cans, which are quite popular with ultralight backpackers, have bases -that are only about 3¼ inches wide, compared with a pot like the Snow -Peak Trek 1400 (my personal favorite) whose base is a bit over 5 inches -wide. - -With these beer can pots, I consistently clock boils times for two cups -of cool, room temperature water at under 4 minutes with the Super Cat, -while the best I've seen with the much wider Snow Peak 1400 is about -4½ minutes under the same conditions. - - [22][Beer_1492-450.jpg] - - Beer can cook pots with Super Cat stoves [23](+) - The Fosters can on the left includes a silicone lip guard - from [24]Ultralight Outfitters - -Much of the reason for the speedier beer can boil times is related, of -course, to the material from which these vessels are made. The very -thin aluminum walls of the cans conduct heat more efficiently than -thicker titanium walls of the Snow Peak pot, partly offsetting the -effects of their less-than-optimal shapes. And to be fair, in a -titanium-to-titanium comparison, the Snow Peak 600 mug, whose base is -about the same with as the beer can pots, requires 15% to 20% more time -to boil two cups of water than does the wider Snow Peak 1400, whose -walls are of about the same thickness. - - [25][Snow-Pots_1495-450.jpg] - - Snow Peak 1400 (L) and Snow Peak 600 (R) - with Super Cat stoves [26](+) - -But my point here is even when using fairly narrow pots, a significant -amount of energy transfer occurs when a stove's flame wraps around the -pot bottom and travels up the sides. Accordingly, I think you'll be -happy with the performance with the standard 3 ounce can when used with -just about any reasonably-sized cook pot. - -Just to be sure, I've constructing stoves from narrower aluminum cans -like those used for Red Bull energy drinks. Those cans are about -2 inches in diameter versus 2.4 inches for aluminum pet food cans -(i.e., are about 83% as wide) and I have seen no significant difference -in boil times. - - [27][Snow600_1499-450.jpg] - - Red Bull sized stove with Snow Peak 600 titanium mug [28](+) - -. - __________________________________________________________________ - -Disclaimers and Safety Notes - __________________________________________________________________ - -Disclaimers - -Before proceeding, I should point out that I am not a chemist, nor an -expert in stove technology. I am just a backpacker who struck upon -something interesting a few years ago that I felt was worth sharing -with my fellow hikers. - -If you decide to build your own Super Cat, you must assume all risks. I -obviously can't guarantee your safety nor indemnify you against -accidents. - -While there are a number of hazards associated with any backpacking -stove, an alcohol stove like the Super Cat probably has more than its -fair share, as I discuss in the next section. That said, as long as -you're careful, building alcohol stoves can be safe and a lot of fun, -perhaps even bordering on addictive for some. - -I should also mention that when researching existing stoves prior to -developing the Super Cat, I found many clever and well-tested designs -available. Nonetheless, I had an idea for a type of stove that didn't -seem to be represented by any of the models I read about, though it's -certainly possible that someone has employed this design before. If so, -I apologize for the lack of attribution, but note that I did arrive -independently at all of my conclusions. - -Safety Notes - -Experienced outdoors people already understand that any backcountry -stove is potentially dangerous and should be handled with great care, -especially when operated in the vicinity of a tent or tarp. Alcohol -stoves like the Super Cat, however, are probably even more hazardous -than some other types for reasons that are discussed below. - -CARBON MONOXIDE - -All backcountry stoves can emit fair amounts of carbon monoxide (CO) -which can be deadly if concentrated in closed spaces. The best review -I've seen of hiking stoves and CO was prepared by Roger Caffin, an -expert who writes for [29]backpackinglight.com. - -In Part 4 of his excellent series of research articles, Roger studied -the emissions of ten commercial alcohol stoves and concluded that: - - "...each of these alcohol stoves emits more CO than the best -canister stoves... all should be considered extremely dangerous in any -confined space." - -To my knowledge, the Super Cat has never been tested for CO emissions, -a task that requires a unique laboratory setup. I have no reason to -believe, however, that the carbon monoxide generated by the Super Cat -would be much different from any of the stoves Roger tested. -Accordingly, you need to be especially careful when operating the Super -Cat indoors or inside a tent vestibule. Without plenty of fresh air -ventilation, carbon monoxide can kill you. - -By the way, Roger's article [30]can be found here. To read the full -text, you'll need to be a BPL online subscriber (currently $24.99 per -year); otherwise, only the abstract will be available. - -FIRE HAZARDS - -Because fuel is burned in an open container, an alcohol stove like the -Super Cat can present a significant fire hazard. Unless the stove is -anchored to the ground or to a windscreen like the [31]Fire Bucket, -it's fairly easy for the stove to tip or blow over during operation. -And as you might imagine, spilling flaming alcohol on you and your gear -is a great way to ruin your day. - -Likewise, when using the Super Cat, make sure that all combustibles are -positioned well away from the vicinity of the stove and that there's a -water source available if things go seriously wrong. Unlike grease or -petroleum fires, which are often spread when water is applied, alcohol -fires can usually be safely doused by drowning. Other less drastic -methods of stopping the Super Cat, such as depriving it of oxygen, are -discussed below. - -Fires can sometimes also start with alcohol stoves because they operate -so quietly and burn with a flame that's nearly invisible in daylight. -You need to be especially careful to keep flammables (like synthetic -clothing) away from your stove if there's any chance it could be -running. Probably the best method to confirm operation if you're -uncertain is to place your hand near the stove or its windscreen to -feel for warmth. - -Petroleum-Based Fuels -I would also counsel you not to use the Super Cat, or any alcohol -stove, with petroleum-based fuels such as automotive gasoline, kerosene -or white gas (Coleman fuel). With lower boiling points, these fuels are -more volatile than most alcohols and are dangerous to burn in open -containers. Because they're heavier than air, petroleum vapors can pool -in low-lying areas and explode when exposed to flame. - -And in case you're tempted to try a higher energy content fuel (like -white gas) in the Super Cat, you should also know that I've already -tried many of them and they just plain don't work. They typically burn -with a low-temperature, yellowish, sooty flame that won't pressure in -this stove. These liquid fuels only work effectively when vaporized -under fairly high pressures and temperatures in stoves like the MSR -WhisperLite. - -Silnylon Shelters -Finally, a special reminder to ultralighters who might be using -silnylon tarps or tents. Standard silnylon (i.e., the kind that's not -additionally treated with polyurethane) is not a fire-retardant fabric -and will burn fairly quickly if exposed to a flame. - -FUEL TOXICITY - -When compared with (iso)butane/propane canister stoves, liquid fuel -stoves can present the additional hazard of direct exposure to toxic -chemicals. - -Denatured alcohol and yellow Heet are the most commonly burned fuels in -alcohol stoves, at least here in the United States. While a more -detailed discussion of these substances is included in the "[32]Super -Cat Fuels" section below, I'll just concentrate here on the potentially -harmful effects of one of the key ingredients in these fuels: Methanol. - -Most denatured alcohols contain some amount of methanol, which a toxic -form of alcohol that's intentionally added to ethanol to render it -undrinkable. Methanol, which is used in a wide range of applications, -is also known as methyl alcohol, wood alcohol, carbinol, wood naphtha -and wood spirits. - -Poisoning Hazards -The problem with methanol is that it can be toxic to humans when -ingested, inhaled, or absorbed through the skin. Historically, the most -common form of methanol poisoning has occurred orally. Consumed in -sufficient quantities, methanol can quickly lead to blindness and -death, primarily through the formation of formaldehyde in the liver -when the substance is metabolized inside the body. - -This form of poisoning is perhaps best known in connection with -drinking illicit liquor (such as moonshine) that contains methanol, -sometimes added intentionally by unscrupulous distillers as a proof -extender. Most backpackers probably don't need to worry about -accidentally drinking methanol, however. Instead, exposure is more -likely to occur through inhalation or absorption through the skin. - -After plenty of Internet research, it's still not clear to me at what -exposure levels methanol becomes dangerous through these two -mechanisms. Perhaps the studies have been done, but I've not found -them. There is universal agreement, however, that the risks are real. -As noted in the [33]Wikipedia methanol article: - -"...Dangerous doses will build up if a person is regularly exposed to -vapors or handles liquid without skin protection." - -The truth may be that nobody knows for sure at what point inhalation -and skin exposure becomes unsafe. I would simply offer the following -obvious advice to any backpacker who might elect to use methanol-based -fuels: - * Avoid breathing alcohol vapors, whether burned or unburned. - * Use a fuel bottle and filling system that minimizes the chance that - you'll spill alcohol on your hands or clothing. If spillage does - occur, promptly wash the affected surfaces. - * Be especially careful not to allow alcohol fuel to leak into your - water or food supply while you're on the trail. Most backpackers - carry their fuel bottles in an external pack pocket in such a way - so that if leakage were to happen, there would be little chance of - contaminating food or water. - -I will finally note that denatured alcohol products often contain other -toxic ingredients besides methanol. Methyl isobutyl ketone, acetone, -ethyl acetate, rubber solvent and other hydrocarbons are frequently -added to ethanol as denaturants, each of which is potentially -dangerous. Because their concentrations are usually small, however, -these other ingredients may not represent quite the same magnitude of -risk as does methanol. - -SUPER CAT-SPECIFIC ISSUES - -In addition to the general risks described above, the Super Cat -presents a few unique challenges that are discussed in the -"[34]Starting and Using the Stove" section below. Fortunately, all of -these Super Cat-specific risks can be easily minimized or eliminated by -using either the techniques or accessories that are likewise discussed -in that section. - -LIVING HAPPILY IN SPITE OF THE ODDS - -While I feel it's important to inform you about potential dangers, I -hope I haven't discouraged you from building and using a Super Cat. - -The truth is that alcohol-based stoves are generally accepted as safe -by most knowledgeable backpackers, as long as the user exercises a fair -measure of common sense. I've been working with and testing these -stoves for many years without serious incident and accordingly, would -encourage you to give the Super Cat a try. - __________________________________________________________________ - -Materials - __________________________________________________________________ - -CAN SELECTION - -At the core of the Super Cat project, of course, is an empty, clean -aluminum can. The 3 ounce size that's widely found at most grocery -stores and used for products such as cat food and potted meat sandwich -spreads is probably the best all-around choice for the reasons -discussed above. Examples of this type of can are shown below. - - [35][3oz-cans_1502-450.jpg] - - Samples of products packaged in 3 ounce aluminum cans [36](+) - -You'll find that even among similar can types, there will be some -variations in dimensions and weights. For example, the Hormel potted -meat can shown above is slightly taller than the Fancy Feast cat food -can, even though both contain 3 ounces of product. Most of these minor -variances will have little or no impact on stove performance, however. - -Aluminum vs. Steel -One factor than will have a major impact on stove performance is the -metal from which the can is stamped. It turns out that not all 3 ounce -food cans that are made from aluminum. Some, such as those shown below, -are constructed from steel. - - [37][Steel_1488-450.jpg] - - Samples of 3 ounce steel cans [38](+) - -While some of these steel cans are perhaps useable for Super Cat -stoves, there are some noteworthy issues: - 1. A 3 ounce steel can will probably weigh about ¾ ounce, or about - three times as much as a comparable aluminum can. - 2. Although perhaps more durable than similar aluminum cans, steel - cans are more difficult with which to to work. Most standard office - hole punches won't be able to penetrate the sidewalls, so you'll - either need to drill or use a sheet metal ("Whitney") punch such as - that described in the "Tools" section below. - 3. The greater thermal inertia of steel stoves leads to longer cooling - times, which extends the wait before they can be moved, packed or - safely refilled after use. - 4. The thicker walls of steel cans don't conduct heat as efficiently - as the thinner aluminum, which creates very different burn - characteristics. For example, the thermal feedback mechanism - (discussed above) that's necessary to start and keep the pool of - alcohol boiling takes much longer to work. Likewise, steel stoves - tends to run cooler, which contributes to longer boil times. - -The performance results from tests conducted recently in a head-to-head -comparison of aluminum and steel stoves is shown below. Both stoves -were fueled with one fluid ounce of SLX denatured alcohol and used to -heat two cups of cool room temperature water in a Snow Peak Trek 1400 -titanium cook pot to a rolling boil. The fuel in both stoves was also -ignited without external priming mechanisms (such as a priming pan). - - Aluminum stove - - Steel stove - -Prime time * - 25 sec 2 min - -Time to rolling boil (incl prime time) - 4 min, 30 sec 8 min, 45 sec - -Total stove burn time (incl prime time) - 6 min, 45 sec 12 min, 30 sec - -* Prime time = the amount of time from ignition until the surface of -the alcohol begins to boil, which also marks the point at which the -cook pot can be lowered onto the stove. - -Bottom line: unless you have compelling reasons to use steel, I'd -suggest sticking with aluminum. But when shopping for a suitable can, -how does one distinguish between the two, since their appearances can -be very similar? - -One way to tell the difference is to gently press on the sidewall of -the can with your thumb. Aluminum cans will flex fairly easily, while -steel cans have much less "give". - -Another way is to take a scale with you to the grocery store. An -aluminum can that contains 3 ounces (net weight) of product will -probably weigh about 3.3 ounces in total. A similar steel can will -likely weigh over 4 ounces. - -You can also, of course, select products that are known to be packaged -in aluminum. The list below includes a few brands distributed -regionally or nationally in the United States that I've verified (at -least as of the date of publication) are sold in aluminum cans. - - Product ( 3 ounce net weight size ) Manufacturer - -Fancy Feast Gourmet cat foods - - Nestlé Purina PetCare Co - -Elegant Medleys cat foods - Nestlé Purina PetCare Co - -Newman's Own Organic cat foods - Newman's Own Organics - -Some Harmony Farms cat foods * - Harmony Farms Pet Products - -Priority (Safeway store brand) cat foods - Safeway, Inc. - -Companion (Giant Foods store brand) cat foods - Giant Food, LLC - -Wegmans Gourmet (store brand) cat foods - Wegmans Food Markets, Inc - -Hormel Potted Meat Food Product - Hormel Foods, LLC - -Libby's Potted Meat Food Product - ConAgra Foods, Inc. - -* The smaller cans are aluminum, the slightly larger cans are made from -steel - - -PREPARING THE CAN - -Once a suitable can is obtained, you'll want to first remove the label -and clean the interior. I'd also recommend that you remove the gummy -label adhesive using a solvent such as Goo Gone or Goof Off (by the -way, the lubricant WD-40 also does a great job of dissolving many -adhesives and is probably less toxic than most other solvents). - -While some of the residue will eventually burn away if you choose not -to bother, the remainder will tend to stay somewhat sticky. If you -build an an optional stand (more below) that uses a "docking socket" to -hold the stove, the residue will often melt between the stove and the -holder, effectively gluing the two together. This remaining goop will -also sometimes transfer to other items in your pack, so it's best to -remove as much as possible. - __________________________________________________________________ - -Tools - __________________________________________________________________ - -The tools you'll need will depend on how you build your Super Cat, but -are mostly quite simple. For the basic Super Cat described below, all -you'll need are a flexible measuring tape and a felt tipped pen for -measuring and marking ventilation hole positions, and a standard office -punch for making those holes. - - [39][Tools1_1509-500.jpg] - - Simple Super Cat tools [40](+) - -MAKING HOLES - -There are many ways to create vent holes in the walls of the can, but -one of the easiest (and neatest) is with a handheld office paper punch -such as that shown above. Most standard punches are designed to make -holes that are about ¼ inch in diameter, which is about the largest -size you'll want to consider for the Super Cat. Available at most -office supply stores, these punches are also inexpensive and can easily -puncture the soft aluminum. - -Not all of these punches are created equal, however. For example The -$0.97 punch I recently bought at Wal-Mart does not work very well, nor -do any of the dollar store versions I've tried, all of which failed -quickly. On the other hand, the [41]$1.29 model from Staples that's -shown in the photo above has performed very well. - -Online craft stores are another source for quality paper punches in -sizes other than ¼ inch. I actually prefer vent holes that are slightly -smaller at 3/16 inch in diameter because the resultant stove flame -seems to be a little less wind-sensitive than with ¼ inch holes. -[42]Mister Art, for example, offers such punches in a range of sizes. - -Another option is an inexpensive sheet metal punch that is much more -durable than a paper punch. Also known as "Whitney" punches, they can -be purchased for as little as $20 plus shipping from online sources -such as [43]Harbor Freight, that offers both [44]standard and -[45]deep-throated models. These punch kits include multiple die sets -that create holes in up to 16 or 20 gauge (depending on model) steel -sheet metal in a variety of sizes. I own the standard Harbor Freight -model and have found that it's ideal for building Super Cat stoves. - - [Whitney-deep-600.gif] - - Sheet metal ("Whitney") punch - Shown is the deep-throated model with punches and dies - -An electric drill is another obvious choice, though drilled holes tend -to be a little messier than punched holes. One exception are those that -are made with a variable width bit called a "Unibit" that allows for -creating fairly smooth edges. Made by Irwin and Klein, these bits are -available from a variety of online sources and sell for about $20.00. I -haven't tried a one myself, but some Super Cat builders have reported -excellent results with Unibits. - - [46][Drill-300.jpg] [47][Unibit-300.jpg] - Electric drill [48](+) Unibit [49](+) - -Finally, as described in the original Super Cat article, a sharp awl or -similar tool works well and allows for easily making holes of multiple -sizes. The downside is that the holes are not very pretty, but I still -like this method in part because of its simplicity, but also because it -can be easily improvised on the trail using a nail or pocket knife. - - [50][Tools_3389-small.jpg] - - Alternative tools for punching holes and flattening collars [51](+) - -If you employ the awl method, you'll probably also want a pair of -pliers to flatten the ragged "collars" created by the punctures on the -insides of the can. This process is described in more detail further -below. - __________________________________________________________________ - -Super Cat Build Instructions - __________________________________________________________________ - -Note: There are many tools and techniques that can be used to build -Super Cat stoves. The build instructions below are designed to serve as -a starting point, but I'd encourage you to experiment with alternative -construction methods (some are discussed later on). - __________________________________________________________________ - -HOLE SIZES and PATTERNS - -The number, sizes and positions of the vent holes will determine how -well (or whether) your Super Cat works. They will control the fuel / -air mixture, the burn intensity and will also affect how much weight -the stove can support. - -The good news is that a wide range of sizes and patterns will work to -some degree, so the question is selecting the combination that will -optimize the stove for a particular purpose. - -Most of the time, backpackers want a stove that simply boils water -quickly and efficiently. By varying the hole sizes and patterns, -however, it's also possible to build a stove that burns with reduced -heat output, useful perhaps for extended simmering. - -Within limits, increasing the size and number of holes in the sidewall -produces a stove that burns hotter, while smaller and fewer holes will -cause the stove to burn cooler. The prototype stoves below show a few -of the hole patterns with which I've experimented. - - [52][Samples_1504-500.jpg] - - Stove samples show some of the hole patterns tested [53](+) - -The first hole pattern discussed below will create a stove that burns -hot and fast. The stove also burns with a mostly blue flame (with only -occasional bursts of yellow) that flows smoothly from the vents without -the "pumping" action that is sometimes observed when the hole pattern -is not quite right. - -The holes in this design are also made with a standard office paper -punch and are ¼ inch in diameter. As noted above, slightly smaller -holes (I like 3/16") will produce a flame that seems a little less -wind-sensitive, but ¼ inch hole punches are much more widely available -and so will be used for these instructions. - -I'd suggest proceeding as follows: - 1. First, punch a single hole just under the top rim of the can so - that its upper edge is about ¼" below the top edge of the can - 2. Next, using a felt tipped marker (Sharpies work well) and the first - hole as a reference point, mark the centers of subsequent holes - every ½ inch around the can's circumference, inline with the center - of the first hole. This pattern should produce a total of 15 holes. - Now punch the remaining holes to complete the top row. - 3. Punch a single hole in the bottom row that's equally spaced between - two of the top row holes. The top of this new lower hole should be - 1/8 inch beneath the bottom edge of the hole above it. If - positioned correctly the center of this new offset hole should also - be about ½ inch (diagonal measurement) from the centers of each of - the two holes above it. - 4. Finally, repeat Step 2 above, marking and punching the remaining - bottom row holes spaced at ½ inch intervals. - -Note that the dimensions shown in the diagram below assume the use of a -Fancy Feast gourmet cat food can and are delineated in English units -(inches). If you'd prefer to work in metric units (millimeters), you -can click on the link under the caption. - - [54][English.gif] - - Super Cat dimensions using a - Fancy Feast cat food can [55](+) - - [56]Click here to see dimensions in metric units - -When you've finished, your new Super Cat should look the the sample -shown below. - - [57][Can-empty_1506-300.jpg] - - [58][Can-complete_1507-300.jpg] - -Start with a clean, empty -3 ounce aluminum can [59](+) - -Completed Super Cat [60](+) - -Other Hole Creation Methods -If you make vent holes using an awl or most electric drill bits, you'll -notice a ragged-edged "collar" around each hole inside the can. These -collars can create turbulence in the flame jets, so it's best to -flatten them in order to get the smoothest possible gas flow. Use a -pair of pliers with curved pinchers (so that you don't also flatten the -can rim), to gently "smash" down these edges. The photos below -illustrate the process. - - [61][BeforeCrunch_3393-300.jpg] - - Vent holes made with an awl - before flattening the collars [62](+) - -[63][Crunching_3403-300.jpg] - - Flattening vent hole collars [64](+) - - [65][Completed_3398-300.jpg] - - Completed stove [66](+) - -ALTERNATIVE HOLE PATTERNS - -Reducing Heat Output for Simmering -Most popular alcohol stove designs work well for boiling water but are -notoriously difficult to throttle back for simmering. That's because -there are only two ways to reduce the heat output of any stove and most -alcohol heaters can use only the less efficient one. - -The first way to reduce heat output, which offers the finer level of -control, involves limiting the amount of fuel that reaches the flame. -This technique is used, of course, in all canister and commercial -liquid fuel stoves, usually by employing a screw-type fuel valve that's -typically located either at the stove or on a remote fuel bottle. With -almost all alcohol stoves, however, the entire fuel supply is always -available for the duration of the burn, so there's no practical way to -limit its exposure to the flame. - -The second method, which is the only choice available for most alcohol -stoves, involves reducing the amount of oxygen that reaches the flame. -This option, however, is usually much more difficult to control since -even a slight breeze can radically alter the airflow in and around the -stove. - -One technique that's used by a fair number of alcohol stove users is to -add some type of air-restriction shield around either the vent holes of -the windscreen or around the stove itself. Some Super Cat users have, -for example, built "simmer rings" that can be temporarily attached to -the stove in such a way as to block one row of vent holes in order to -reduce heat output. - -Creating airtight seals with these kinds of shields is difficult, -however, and so they often don't work very well. In addition, most -alcohol stove designs don't allow this type of airflow adjustment to be -made in real time while the stove is operating. - -Before proceeding, I should mention that one of the best approaches to -simmering is not to simmer at all, but rather, to cook with retained -heat using either single or double pot cozies as described in August, -2008 article "[67]Three Mods for Your Mug". As many backpackers already -know, this method can save a lot of fuel by preserving the energy -that's already been added to a cook pot during the initial heating -process. For meals that need extended cook times, I'd strongly suggest -that you try this method first. - -Building a "Simmer Cat" -Nonetheless, if you'd like to try simmering with a Super Cat, one way -is to create a second version of the stove that's optimized for this -purpose (let's call it a "Simmer Cat"). This dedicated simmer stove -will likely offer a more reliable way to cook at reduced heat than by -using an add-on that can leak air, and possibly fuel. In addition, a -dedicated Simmer Cat, at least the one described below, will have a -higher fuel capacity than a simmer ring-equipped main stove and thus -can be operated for longer periods of time. - -You can build a Simmer Cat in many ways, but probably the easiest is to -construct the same stove that's described above, but without the bottom -row of ventilation holes. Based upon my tests, this single-row stove -will operate with a bit less than half the heat output as a comparable -model that uses a double row of holes. - - [68][Simmer_1511-450.jpg] - - "Simmer Cat" with a single row of vent holes [69](+) - -A performance comparison between similar Super Cat and Simmer Cat -models is shown below. Both stoves were fueled with one fluid ounce of -SLX denatured alcohol and used to heat two cups of cool room -temperature water in a Snow Peak Trek 1400 titanium cook pot to a -rolling boil. The fuel in both stoves was also ignited without external -priming mechanisms (such as a priming pan). - - Super Cat Simmer Cat - -Prime time * - 25 sec 25 sec - -Time to rolling boil (incl prime time) - 4 min, 30 sec 9 min, 45 sec - -Total stove burn time (incl prime time) - 6 min, 45 sec 15 min, 30 sec - -* Prime time = the amount of time from ignition until the surface of -the alcohol begins to boil, which also marks the point at which the -cook pot can be lowered onto the stove. - -The heat output of a Simmer Cat can be further adjusted by either -adding or deleting vent holes. Obviously, adding a hole is easy, while -deleting a hole usually requires starting over with a new stove, so -it's best to proceed slowly when experimenting. Likewise, hole sizes -can be reduced, though I've found that when using a single row of -vents, holes that are much smaller than 3/16" in diameter will probably -lead to stove that doesn't work at all. - -By the way, if you really think you need real-time control over your -stove's heat output, a completely different approach to simmering is -offered below in the "Accessories" section. Called the "[70]Swivel -Cat", this stove requires a separate pot stand, but allows you to make -flame adjustments while the stove is operating. - -Using a Simmer Cat on the Trail -When preparing a meal that requires a long cook time, most hikers will -probably first want to use a standard Super Cat to bring the meal to a -boil, then transfer the pot to the Simmer Cat for the remainder of the -required time. - -Other Hole Configurations -While the hole configuration discussed above in connection with the -standard Super Cat should work fine under most conditions (including -high altitudes and low temperatures), you might like to experiment with -other sizes and patterns. If so, there are a few things that might be -helpful to know. - -The first is that the fuel capacity is (obviously) defined by the -height of the bottom edge of the lower holes above the base of the can. -The higher these holes are positioned up the wall of the can, the -greater the potential fuel volume. - -The tradeoff, however, is that if the flame jets that emanate from -these bottom holes are too far away from the top surface of the -alcohol, there may not be enough heat transferred to the alcohol pool -to keep it boiling and the stove could extinguish itself, especially in -chilly weather. - -The range of distances, as measured from the bottom of the can to the -bottom edge of the lowest hole, that seem to work are 1/2" to 5/8" -(13mm to 16mm) for double row stoves and 7/8" (22 mm) for a single row -Simmer Cat stove. The approximate fuel capacities of each of those hole -heights is shown below. - - Hole Height Fuel Capacity (fl oz) - 1/2" (13mm) 1.2 - 9/16" (14mm) 1.3 - 5/8" (16mm) 1.5 -7/8" (22mm) - Single row design 2.1 - - -Another variable to keep in mind is that the larger the vent holes, the -more wind-sensitive the stove is likely to be. The largest hole size -I've found that works well is about ¼ inch in diameter. On the other -hand, vent holes that are too small may not work at all. A couple of -Super Cat builders have reported making stoves that use three rows of -very small holes, but I've never been able to get this arrangement to -work (perhaps I'm missing something). - -It's also not mandatory that all vent holes be of the same size. Some -of my earliest Super Cat prototypes (that worked very well) were -constructed using a row of relatively large top holes, along with -slightly smaller holes in the bottom row. - -Also remember not to create so many holes that the structural integrity -of the can is compromised. If you remove too much aluminum, the stove -might not be able to safely support a pot full of water. While the -stove may not actually collapse during operation, the walls might -slowly warp under heat stresses, shortening the Super Cat's life. - -Irrespective of the hole configuration you select, you'll want a mostly -blue alcohol flame (a few short yellow bursts are OK) that flows -smoothly from the vent holes without the "pumping" action that usually -indicates that the fuel / air mixture is less than optimal. - __________________________________________________________________ - -Super Cat Fuels - __________________________________________________________________ - -Fuels that are appropriate for use in the Super Cat, as well as in most -other alcohol stoves, have been widely discussed on the Internet, so I -don't want to simply regurgitate what others have written. One of the -best reviews is available on the [71]Zen Stove website. - -Likewise, the names, availabilities and even colors of these fuels can -vary from country to country. A good resource for international fuel -information [72]can be found here. - -The discussion below is a brief summary of the fuels that are either -used, or might be considered for use, in alcohol stoves and reflects -many of my own experiences. - -DENATURED ALCOHOL - -Over the years, I've tried a wide variety of fuels in the Super Cat. -The best results have consistently come from [73]denatured alcohols, -which usually burn hot and clean with virtually no odor or soot -production. Denatured alcohols are widely available in the United -States, though there is no standard formula for these products among -its various manufacturers. - -Ethanol -Denatured alcohol starts with [74]ethanol, also known as ethyl alcohol, -which is the same type of alcohol that's found in adult beverages and -which has received so much attention in recent years as an alternative -automotive fuel. - -To render the ethanol undrinkable (and therefore not subject to liquor -taxes), a variety of "denaturants" or toxic chemicals are mixed into -the ethanol to convert it into denatured alcohol. In some countries, -dyes (often purple) are also added to help distinguish the product from -clear nontoxic beverages such as water. - -Methanol -One additive that's commonly used is a variety of alcohol called -[75]methanol, also known as methyl alcohol, wood alcohol, wood spirit, -wood naphtha, pyroligneous spirit and carbinol. - -Aside from its use as an ethanol denaturant, methanol is also widely -employed as an industrial and marine solvent, a paint remover, a car -racing fuel, and as a component in shellacs, photocopying compounds and -windshield-washing fluids. - -The biggest problem for backpackers is that unlike ethanol, methanol is -poisonous when ingested, inhaled or absorbed through the skin (see the -"[76]Safety Notes" section above). - -Methanol does, however, have combustion properties that are similar to -ethanol. A comparison of ethanol and methanol, along with the -petroleum-based Coleman fuel that's used in traditional backpacking -stoves (like the MSR WhisperLite) is shown below. - -Ethanol Methanol - -Coleman Fuel -(aka white gas, -naphtha) -** See Note Below - -Energy content -(Megajoules per liter) -23.5 17.9 35.5 - -Energy content -(% of Coleman Fuel) -66% 50% 100% - -Weight -(ounces per fl-oz) -0.82 0.83 0.73 - -Weight -(% of Coleman Fuel) -112% 114% 100% - -Boiling point -173° F 148° F 117° F - -Typical fuel weight * -(7-day backpacking trip) -17.8 oz 23.9 oz 10.5 oz - -* The 50% / 50% SLX blend would require about 21 ounces of fuel for -this trip - -** Special Note: Coleman fuel is included in the chart above for -reference purposes only since it's a fuel with which most backpackers -are familiar. As stated in the [77]Safety Notes section above, Coleman -fuel is most definitely not suitable for use in the Super Cat or any -other alcohol stove. In addition to being a very poor performer in -alcohol stoves, Coleman (or any other petroleum-based fuel) can also be -quite dangerous to burn in any stove not specifically designed for its -use. - ___________________________________ - -Many experienced alcohol stove users prefer denatured alcohol blends -that contain as much ethanol as possible, since it has a higher energy -content than methanol and is also less toxic. - -On the other hand, the boiling point of methanol is lower than ethanol -which means that it will vaporize more easily in cold weather (but -still not as well as Coleman fuel). The brand of denatured alcohol I've -used the most is SLX from WM Barr, which contains roughly 50% ethanol -and 50% methanol. [SLX.jpg] - -At that mix, its blended energy content is about 20.7 megajoules per -liter or 58% of the petroleum-based Coleman fuel. On a volume basis, -that blend is also about 113% of the weight of Coleman fuel, which -means that on a weight-for-weight basis, denatured alcohol contains -about half the energy content of Coleman fuel. - -In other words, to boil the same quantity of water on a backpacking -trip, I'd need to carry twice the weight of denatured alcohol as I -would Coleman fuel. - -With priming, a little waste, and lots of morning coffee, I typically -use about 1½ ounces (by weight) of petroleum-based fuels a day, so a -7-day trip generally would require a total of about 10½ ounces. If I -carried SLX instead, I'd need roughly 21 ounces of denatured alcohol -for the same trip. Of course, there are many other variables, like the -weight differences of the associated stoves and accessories that must -figure into a final weight-efficiency calculation. - -Determining the Ingredients -Processed foods sold in the United States are required to bear labels -that specify their ingredients. There is, however, no such requirement -for denatured alcohol products, so instead, one must turn to a document -that the federal government requires be filed and regularly updated for -every chemical distributed in this country that contains hazardous -components. Among the information required to be reported are the -ingredients and their approximate percentage constituencies. I should -also note that most other industrialized countries, especially Canada -those in the European Union, have similar reporting laws. - -The MSDS -Called a [78]Material Safety Data Sheet (MSDS), one of these documents -is available for every denatured alcohol product sold in the United -States. They can sometimes be found in online MSDS databases, and -sometimes on manufacturers' or retailers' websites. Probably the -easiest way to locate an MSDS for a particular product is to simply -perform an Internet query using "MSDS" and the product name as your -search terms. - -For your convenience, I've also collected the MSDS's for a few popular -brands of denatured alcohol as well as for the two kinds of Heet that -are discussed below. You can [79]find them here. - -No Water, Please -When reviewing these documents, you may note that some brands of -denatured alcohol contain water as an ingredient. It's been my -experience--and apparently that of others as well--that even a little -water can have a significantly negative impact on stove performance. - -One example is Parks brand denatured alcohol. According to its 2002 -MSDS, it contained 87% to 92% ethanol but also 5% to 10% water, a fact -that might account for some of the negative backpacker comments that -I've read about this product when used as a stove fuel. In fairness, -I should also point out that in an updated MSDS released in December, -2006, water is longer listed as an ingredient, so perhaps their formula -has changed. - -HEET FUEL-LINE ANTIFREEZE - -After denatured alcohol, the second most popular fuel for alcohol -stoves is probably a product called Heet. Manufactured by Chicago-based -[80]Gold Eagle Company, Heet is an automotive and small engine fuel -additive that is marketed as a fuel-line antifreeze and water remover. -I suspect that its popularity among hikers is largely related to its -wide availability, especially in the northern U.S. - -Sold in 12 fluid ounce plastic bottles at automotive stores, gas -stations, and variety stores such as Wal-Mart, Heet is available in two -varieties. - -Regular Heet ("Yellow Heet") -The first variety is named just "Heet" and is packaged in a yellow -bottle (and hence often called "Yellow Heet"). It consists, according -to its MSDS, of 99% methanol, which was discussed above. If you're -going to burn Heet in your Super Cat, this is the kind you want. -It burns with a clean, blue flame similar to that seen with most -denatured alcohols. A 12 fluid ounce bottle currently costs $1.50 to -$2.50. - -Compared with a denatured alcohol product like SLX (which contains -about 50% each of ethanol and methanol), Yellow Heet has a slightly -lower energy content, but also a slightly lower boiling point, so it -should ignite a bit more easily in cold weather. - -Because it's almost pure methanol, however, Yellow Heet is also more -toxic than most denatured alcohol fuels. The toxicity of methanol is -discussed at some length above in the "[81]Safety Notes" section. - - [82][Heet_1513-450.jpg] - - Methanol-based Heet (yellow) and - isopropanol-based Iso-Heet (red) [83](+) - -Iso-Heet ("Red Heet") -The second variety is called Iso-Heet, which is packaged in a red -bottle (and hence often referred to as "Red Heet"), and consists, -according to its MSDS, of 99% [84]Isopropanol. - -Also known as isopropyl alcohol, rubbing alcohol, 2-propanol or IPA, -this is a third type of alcohol (after ethanol and methanol), that -hikers sometimes burn in alcohol stoves. A 12 fluid ounce bottle -usually costs $2.00 to $3.00. - -Although it's an alcohol, isopropanol has about the same energy density -as petroleum-based fuels like white gas at 30.4 megajoules per liter, -yet weighs about the same as ethanol and methanol. Unfortunately, it -also burns much like petroleum-based fuels in alcohol stoves, which is -to say, not very well. - -When ignited, Red Heet burns with a low temperature, yellow flame that -will quickly deposit a coating of black soot on cook pots. If allowed -to burn long enough, however, it will usually produce enough heat to -bring a couple of cups of water to a boil. Most experienced users will -chose Red Heet only if there's no better alcohol fuel available. - - [85][Red-Heet-Flame_1574-450.jpg] - -Red Iso-Heet burns with a yellow, sooty, low-temperature flame [86](+) - -OTHER FUELS - -Rubbing Alcohol [Ethyl-Rubbing.jpg] -The term "[87]rubbing alcohol" is somewhat ambiguous since it can be -applied to products that are made either with ethanol or with -isopropanol, both of which are discussed above. - -The ethyl alcohol version is composed of mostly ethanol that's been -denatured (made undrinkable) by adding a combination of acetone and -methyl isobutyl ketone. Usually sold in concentrations of 70% by -volume, the remaining 30% is primarily water. Because of its high water -content, this version does not work very well in alcohol stoves. With -the Super Cat, in particular, its unlikely that the stove will -pressurize with this fuel. - -The isopropanol (or isopropyl) version of rubbing alcohol is the same -compound chemically as the Red Heet discussed above, except just with -more water. Usually sold in 70% and 91% (or sometimes even 99%) -concentrations by volume, neither is a very good stove fuel. The 70% -concentration, in fact, hardly burns at all, while the 90%+ -concentrations will generally work, but with the sooty flame of Red -Heet. - -Distilled (Drinkable) Spirits [Everclear.jpg] -Distilled (drinkable) spirits are normally produced through a process -that can produce a maximum ethanol concentration of 95.6% by weight. -Commercial products containing this high level of ethanol are usually -sold as "grain alcohol" are available in most, but not all, -jurisdictions within the United States.* - -One of the most popular brands of grain alcohol is Everclear, which is -sold in both 151-proof and 190-proof varieties ("proof" = 2 times the -alcohol concentration by volume). A 750 milliliter bottle of 190-proof -Everclear typically sells for $18 to $25 (usually plus sales tax), -which makes it an expensive stove fuel. - -One 750ml bottle would fuel approximately 25 normal burns in an alcohol -stove. Or in other words, if you include sales tax, it would cost about -$1.00 every time you boiled two cups of water (I can think of better -uses for Everclear). - -Because Everclear is not available in my area, I've not tried it -myself, but others have said that in spite of its ~5% water component, -it burns well in most alcohol stoves. - -During my early Super Cat testing, I did try Bacardi 151-proof rum as a -fuel (75.5% ethanol by volume). The Bacardi burned cleanly, but -probably because it still contains almost 25% water, the internal vapor -pressure was not quite sufficient to allow the stove to pressurize -(i.e., the flames could not switch to the outside of the stove). -Bacardi 151 could therefore be used as a fuel for the Super Cat, but -only in non-pressurized mode using a separate pot stand. - ___________________________________ - -* According to the Wikipedia "...It is illegal to sell the 190-proof -variety [of grain alcohol] in some states of the United States, viz.: -California, Florida, Hawaii, Maine, Massachusetts, Michigan, Minnesota, -Nevada, New York, Ohio, Pennsylvania, Virginia, and Washington. In some -of these states, the 151-proof variety may be sold. In Canada, it is -sold in Alberta but not in Saskatchewan, Manitoba and most other -provinces. - -Esbit Tablets -During my 2004 Super Cat testing efforts, I was curious to see if the -stove would work when burning Esbit solid fuel tablets that are popular -with many long-distance backpackers. Though the heat output from the -tablets seemed to be about the same as with denatured alcohol, the -combustion chamber would not pressurize at all. The tablets also left a -gummy reside inside the stove and on the underside of the pot that -caused the two to be temporarily "glued" together. Science project net -result: doesn't work. - - [88][Fuels_3400-475.jpg] - - Some of the fuels tested during early development [89](+) - -Laboratory (Reagent) Grade Ethanol -As noted above, high-concentration ethanol is normally produced through -a fermentation and distillation process that is capable of producing a -[90]maximum alcohol concentration of 95.6% by weight, where the -remaining 4.4% is mostly water. [Lab-grade.jpg] - -To produce the kind of waterless ethanol that's required in many -automotive and laboratory applications, the remaining H[2]0 must be -removed through a chemical drying process that often involves the -compound benzene. - -The resultant "laboratory" or "reagent" grade product is a kind of -denatured ethanol that contains virtually no water, but which is still -not drinkable, either because there are trace amounts of toxic benzene -remaining, or because small amounts of denaturants such as methyl -isobutyl ketone or methanol have been intentionally added. - -Nonetheless, this 95%+ pure, waterless ethanol is probably the best -alcohol stove fuel available. Though it doesn't vaporize in cold -weather quite as well as pure methanol, its high energy content (31% -greater than methanol) and low toxicity (relatively speaking) make it -very appealing. And at $6.00 to $7.00 per quart, the cost is also -roughly comparable to many denatured alcohol products. - -The bad news is that in the United States, distribution of laboratory -grade ethanol is restricted to businesses, governments and educational -institutions. However, if you're in a position to obtain some from your -school or workplace, you might want to give it a try in your Super Cat. - -Distilling Your Own Ethanol -The home production of ethanol in the United States is generally -banned. One exception allows for the distillation of ethanol for use -solely a fuel, though the current law does not specify exactly what the -term "fuel" means. - -The U.S. Department of the Treasury's [91]Alcohol and Tobacco Tax and -Trade Bureau (TTB), is charged with licensing private ethanol "plants", -a process that starts by filing a [92]5-page form with the agency. Once -the no-fee document has been received, the TTB must make a -determination about whether the proposed use falls within the agency's -interpretation of the term "fuel". While it might seem that use in an -alcohol stove would qualify, my guess is that it probably does not. The -following statement appears on the current TTB website: - -"...TTB has received requests to use fuel alcohol in the manufacture of -products such as charcoal lighter fluid, firelighter gel, and chafing -dish "fuel." We must turn these requests down because these products -are not within the intent of the law restricting the alcohol to "fuel -use." - -While it's unlikely that most backpackers would bother attempting to -make their own alcohol fuel, there are almost certainly a hardcore few -that have tried it (legally or not). There are a great many Internet -resources available that offer both the instruction and the equipment -necessary to distill ethanol at home. - -Ethanol 85% ("E85") -Containing approximately 85% ethanol and 15% gasoline (or other -hydrocarbons) by volume, E85 is sold as an automotive fuel in the -United States and other countries primarily for use in "Flexible-Fuel" -vehicles that have been modified to run on this high-octane, -alternative to regular gasoline. [E85_logo.jpg] - -According to the [93]Wikipedia, there are currently "...1500 public E85 -fueling stations available in the United States (out of 176,000 -worldwide), at prices over 30% less than regular gasoline (when -discounting the reduced fuel economy of E85), primarily in the -corn-growing Midwest..." - -I've not personally tried E85 in a Super Cat stove, but I've heard from -those who have. They've reported that although the fuel contains only -about 15% gasoline, it burns with substantially the same properties as -regular gasoline. The resultant low-temperature, sooty flame apparently -burns mostly yellow and fails to pressurize in the stove, making E85 -largely unsuitable for use in a Super Cat. If you have any different -experiences with E85, I'd very much like to hear from you. - -Petroleum-Based Fuels -Petroleum-based fuels such as automotive gasoline, kerosene or white -gas (Coleman fuel) are discussed about in the "[94]Safety Notes" -section above. Bottom line: they're more dangerous than alcohols fuels -and they also just plain don't work. - -CARRYING AND DISPENSING YOUR FUEL - -Suitable Fuel Bottles -A question that comes up regularly on Internet backpacking forums -relates to the kinds of containers that can be safely used to transport -alcohol fuels on the trail. - -The good news is that almost any plastic or metal container will work -just fine. Soda or water bottles made from common high-density -polyethylene (HDPE) or PET (polyethylene terephthalate) are chemically -stable enough that they won't react with most alcohol fuels. - -Some lightweight backpackers prefer collapsible plastic containers such -as those made by [95]Platypus or [96]Evernew, but I personally find -it's more difficult to manage a "floppy", soft-sided container than one -with rigid sidewalls. - -Soda bottles (i.e., those used to package carbonated beverages) are a -popular choice because they're lightweight, come in a large variety of -capacities and are free. Because they're designed to contain beverages -that are under a fair bit of internal pressure, they're also quite -strong. One source, in fact, suggests that soda bottle manufacturers -typically design their products to withstand internal pressures of at -least 10 atmospheres (~150 psi) before bursting, even though the -beverages themselves are normally packaged at only 2 atmospheres. - -Most soda bottles made in the U.S. also have standard-size screw tops -that are compatible with those used on the Platypus and Evernew -soft-sided containers. Accordingly, they will accept accessories such -as the [97]FireLite Red Spout caps from backpackinglight.com, or the -[98]push-pull caps from Platypus. - -It's interesting to note that bottles used to package many -non-carbonated water products have a similar thread design (that's -mostly standard among these types of bottles), but they're just -different enough from soda bottles that the caps usually can't be -interchanged. - - [99][Soda_1515-450.jpg] - - Common PET soda bottles are great for transporting alcohol fuels - The middle bottle is equipped with a Platypus push-pull cap -and the bottle on the right with a BPL FireLite Red Spout cap [100](+) - -Whatever container you choose, you'll want to make sure that the cap is -fully leak-proof. Fuel bottles can be subjected to several kinds of -stresses on the trail, including those associated with internal -pressures that can build significantly with altitude gains or -temperature increases. - -I've found that the push-pull or twist caps used on some disposal water -bottles don't hold up very well (though others fare better). Likewise, -certain flip-top caps, such as those used on most brands of hand -sanitizers, will pop open fairly easily under only moderate pressure. - - [101][Cap1_1517-300.jpg] - - [102][Cap2_1518-300.jpg] - -Some disposable water bottle -caps tend to leak easily [103](+) - -Flip-top caps can sometimes -pop open under pressure [104](+) - -On the other hand, my experience has been that folding-spigot caps of -the type supplied with some sizes of the familiar [105]Campsuds or on -certain [106]plastic bottles sold by REI, are quite durable and -leak-resistant as are the tilt-top caps I've tried. Likewise, the -Platypus push-pull and BPL FireLite red spout caps mentioned above are -also recommended. - - [107][Cap3_1520-300.jpg] - - [108][Cap4_1522-300.jpg] - -This tilt-type cap is quite -leak and pop-open resistant [109](+) - -A folding spigot is even more -leak and pop-open resistant [110](+) - -If you're taking a trip of more than a few days, you might want to -consider carrying two fuel bottles. The larger, which would contain the -majority of your alcohol, could have a standard, non-dispensing, -leak-proof cap, while a second smaller (probably 4 to 8 ounces) -"working" bottle could be used for actually fueling your stove. The -smaller bottle, perhaps equipped with a spigot-type dispensing cap, -will be much easier to handle around camp and can be refilled from the -larger bottle as necessary. - -By the way, there's a good summary of fuel bottle choices on the -[111]Zen Stoves website. And oh yes, it's also a good idea to mark your -fuel bottle, especially if using a water or soda type, so that it -indicates that the clear contents are flammable, poisonous, and are not -to be confused with drinking water. Though you'll know the difference, -someone else who might have need to access your pack (perhaps in an -emergency) may not. - -Measuring and Dispensing Fuel -There are several popular methods for measuring and dispensing fuel to -your stove. One obvious way is to carry a lightweight kitchen measuring -spoon that can be filled to an appropriate level from your fuel bottle. -If you use a bottle with a wide enough mouth, you might even be able to -dip the spoon into the bottle to scoop the fuel, rather than having to -pour the fuel onto the spoon. - -A one-tablespoon size measurer works well because 2 tablespoons = 1 -fluid ounce, which is a normal fuel "load" for the Super Cat stove. If -you need to measure quantities in other than ½ ounce increments, it's -fairly easy to estimate the differences with this size spoon. - - [112][Measure_1530-450.jpg] - - One-tablespoon fuel measurer along with - 8 fl-oz "working" fuel bottle with folding spigot cap [113](+) - Weights: spoon = ¼ oz, bottle = 1 oz - -If you like this idea, I'd suggest selecting a measuring spoon with a -handle long enough to minimize the chance that you'll end up with -alcohol on your hands, since as noted in the "Safety Notes" section, -most alcohol fuels contain methanol, which can be toxic when absorbed -through the skin. - -Another measurement option is to mark the Super Cat with lines -scratched into the inside walls using a nail or awl at ½ fluid ounce -fill increments. You can establish those increments using a -one-tablespoon measuring spoon and water, marking the level each time -you add a tablespoon (½ fluid ounce) of liquid. - -A third option is to carry a bottle that includes a built-in measuring -chamber. The bottles sold by [114]Brasslite are inexpensive, use -spigot-type dispensing caps, and are available in either 8 or 16 ounce -sizes. Though I've not tried them myself, I understand they work well. - -Similar dispensing-reservoir bottles are also used to package a variety -of automotive fuel additives and are widely available in auto parts -stores. Likewise, most of the [115]Coolbrew coffee products are sold in -similar bottles. I would still prefer the Brasslite models, however, -because the discharge port is equipped with a cap that doesn't need to -be removed when fuel is dispensed. - __________________________________________________________________ - -Starting and Using the Stove - __________________________________________________________________ - -SAFETY FIRST - -As mentioned above in the "[116]Safety Notes" section, all alcohol -stoves emit some level of carbon monoxide, so you'll want to work in a -well-ventilated room if you decide to test your Super Cat indoors. I've -done a great deal of stove testing in my basement without problems, but -I make sure to keep the door and windows open and as much air moving -inside as possible. - -You'll also want to work in an area that's clear of anything that could -catch fire if something goes wrong. I always keep my work area clear of -combustibles and generally operate the stove inside of a 12" wide -circular metal pan of the type used for automotive oil changing. -If I somehow manage to tip the stove over during operation, the pan -will confine the flames. - -In addition, I also always have a "snuffer cup" (described below) handy -to extinguish the stove through suffocation if necessary, as well as a -source of water nearby should things really start to get out of hand. -Note that unlike like petroleum-based fires that often spread when -water is applied, alcohol-based flames can usually be quickly -extinguished by drowning. - -FUELING and LIGHTING - -The exact manner in which you fuel and light your Super Cat will depend -in part upon the accessories (if any) that you employ. For example, if -using a windscreen like the [117]Fire Bucket, you'll need an ignition -technique that's appropriate for this type of wind barrier. Likewise, -if using an optional stand that has a built-in primer pan, ignition -will be a bit different than that discussed below. - -For purposes of simplification, I'll describe fueling and lighting a -"naked" Super Cat stove that's set up in a wind-free environment. -Specific recommendations about alternative techniques that might be -appropriate when using certain Super Cat accessories are included in -the same sections where the construction and use of those options is -discussed. - -Step 1: First, position the stove on a stable surface that won't be -damaged by high temperatures. The bottom of the stove will get very hot -during operation, so don't test it, for example, directly on your -kitchen counter. Also be certain that the stove is sheltered from -winds. The Super Cat is extremely lightweight and you don't want it to -blow over while burning, possibly spilling flaming alcohol on you or -your equipment. - -Step 2: Next, measure one fluid ounce of alcohol fuel and pour it into -the bottom of the stove. Never, of course, fill a stove that is still -hot from a previous operation - it should be cool to the touch when -adding fuel. Be sure to clean up any spills on your hands or other -surfaces before proceeding. Also, place any flammable items (like -matches or your fuel bottle) well away from the stove. - -Step 3: Now ignite the fuel, probably most easily accomplished by -extending a lighted match through one of the lower vent holes, or -alternatively, into the stove from the top. Once the fuel has ignited, -flames will emerge through the top, though they may be difficult to see -in bright daylight. Placing your hand near the top of the stove will -allow you to feel the warmth in order to confirm ignition. - - [118][Lighted1_3406-450.jpg] - - Fuel ignited [119](+) - -Step 4: Wait 20 to 30 seconds to allow the flames to warm the both the -stove and liquid alcohol, during which time you'll note an increase in -heat output. This warm-up process is often referred to as "priming" and -is usually complete when you can see the surface of the alcohol pool -bubbling (boiling). -You can now place your pot directly on top of the stove, making sure -that it both covers completely, and is centered over, the top stove -opening. With the pot in place, the combustion chamber should now -pressurize and the flames should shift from emanating from the top of -the stove to emerging from the side vent holes. - - [120][Lighted2_3427-450.jpg] - - The Super Cat in operation [121](+) - -Note that if the flames are extinguished when you place your pot on the -stove, then your Super Cat is probably starved for oxygen (i.e., it's -running too "fuel rich"). To fix the problem, either add a few more -vent holes or enlarge the existing ones slightly. Proceed slowly with -this process, however. Too much oxygen will cause the flame to become -"fuel lean" and turn yellow, significantly reducing the efficiency of -the stove. - -Now cook or boil for the desired time. You'll find that one fluid ounce -of fuel will probably last for 7 or 8 minutes, which is usually plenty -of time to bring two cups of water to a boil. Air and water -temperatures, wind conditions, elevation, and other factors will affect -your boil times, so you can adjust your fuel "load" as appropriate. - -To maximize efficiency, it's best to use a tight-fitting lid on your -pot and to surround the stove and pot with a windscreen if there's even -the slightest breeze (more on windscreens below). - -OPERATIONAL PRECAUTIONS - -Be especially careful if you need to remove the pot from the Super Cat -while the stove is in operation. Some of the things that can happen: - 1. Lifting the pot quickly and vertically off the stove can create a - momentary vacuum inside the combustion chamber. The flames on the - sides of the stove will disappear, but an instant later, will - likely re-appear with a "whoosh" back inside of the stove. - What's happening is that the expanding alcohol gases go unburned - for a moment when the outside flames are extinguished, but then - ignite again inside. I don't think this phenomenon is particularly - dangerous, though it can be a bit startling the first time it - happens. It's not nearly as significant, however, as the flare-ups - that can sometimes occur with white gas stoves when they ignite. - The best way to prevent this from happening is to lift the pot - slowly and move it sideways off the burner. This way, the - transition from outside flames to inside flames can occur smoothly, - without a flame-out/re-ignition cycle. Should the flame extinguish, - but not re-ignite on its own, you'll need to manually re-light it. - 2. Sometimes during operation, a little alcohol might collect on the - underside of your pot. When you remove the pot from the stove, this - alcohol can continue to burn for a few moments, making it appear as - though the bottom of your pot is on fire. This small flame is easy - to extinguish, however, by either blowing it out or by setting the - pot on the ground to smother it. - 3. If the bottom of your pot or the top rim of the stove becomes gummy - with cooking residues, the stove could (because it's so - lightweight) actually stick to the pot bottom. When you then lift - the pot, the stove could lift along with it. A moment later, it - could also "un-stick" and fall, spilling flaming alcohol - everywhere. To avoid this problem, always keep the pot bottom and - top stove rim free of sticky substances. - -STOPPING THE STOVE - -Most of the time, you'll probably just allow the Super Cat to burn -itself out after a cooking operation. If you want to deliberately stop -the stove before the fuel is spent, however, there are at least of -couple of methods. - -Before proceeding, I should emphasize that it's almost always a bad -idea to attempt to blow out the flame in an operating Super Cat for at -least two reasons: (1) It probably won't work, since you'll just be -adding oxygen to make the flame burn hotter (the "blacksmith forge" -effect); and (2) if you blow hard enough, you might accidentally cause -flaming alcohol to splash outside the stove through a ventilation port, -perhaps starting a fire nearby. - -Instead, a Super Cat can be reliably stopped as follows: - -1. In an emergency, you can douse the stove with water. As noted -above, the flames can be extinguished in this way without concern about -spreading them (as with a grease fire). - -2. A more graceful technique is to simply deprive the flame of -oxygen. One way to suffocate the burn is to use your empty cook pot as -a "snuffer" by inverting it over the stove. The less air that's trapped -under the pot, the more quickly the flames will extinguish. I normally -use a Snow Peak Trek 1400 titanium cook set (shown in the photos above) -whose top is also a 2-cup fry pan. When this fry pan is used as a -snuffer, the flame is usually extinguished within a second or two. -Because an empty cook pot may not always be available, however, a more -dependable method is to construct a dedicated "snuffer cup" from any -lightweight aluminum can that's slightly larger than the stove. See the -"[122]Accessories" section below for more information about building -and using a snuffer cup. - - [123][Stove-w-Snuffer_1523-450.jpg] - - Super Cat stove with a "snuffer cup" [124](+) - See "[125]Accessories" section below for build instructions - -RECOVERING UNBURNED FUEL - -If there's unburned fuel remaining in the stove after a "snuff-out", -you'll have to decide whether or not to try to recover it. If the -amount is small or if it contains debris or other contaminants that -you'd rather not empty into your clean fuel supply, you might elect not -to bother. In this case, any alcohol left inside the stove will quickly -evaporate. - -However, if the amount is significant, you'll probably want to salvage -the leftovers. Because of the side vent holes, however, a Super Cat's -unburned fuel usually can't just be poured back into the fuel bottle -without spillage. - -My preferred removal technique is to suction the remaining fuel using a -plastic eye dropper such as that made by Nalgene and [126]sold by REI -for $0.30. I've used this dropper for some time (which is so light that -it doesn't register on my scale) and it works very well. - - [127][Eye-dropper-450.jpg] - - A plastic Nalgene eye dropper - can quickly recover unburned fuel [128](+) - -Another option, if you carry a snuffer cup, is to quickly dump the -stove into the snuffer cup so that the fuel can't leak through the side -vent holes. A small notch that's either bent or cut into the inside rim -edge of the snuffer cup will allow the fuel to be easily pored back -into your alcohol bottle (more below on this idea in the -"[129]Accessories" section). - -EXTENDING THE BURN TIME - -The fuel reservoir capacity of the standard Super Cat described above -is around 1½ fluid ounces, which if full, should provide a burn time of -up to 12 minutes or so (depending on conditions). To increase the -effective burn time, one choice is to use two stoves, moving the pot -back and forth between them. - -As stove #1 shows signs of burning out, stove #2 can be lighted and the -pot transferred a few moments later. Stove #1 can be allowed to cool, -then re-filled and re-lighted if desired. The total burn time in this -case would be limited only by the available fuel supply. By the way, -I refer to this technique as the "Super Cat shuttle" and while it works -well in calm conditions, it also requires using two separate -windscreens when it's windy. - -Another obvious way is to increase the volume of the stoves, but there -may be problems with getting the stove to pressurize as discussed -above. One Super Cat builder, Jason Klass, has developed a higher -capacity version of the Super Cat for use mostly in cold weather that -he calls the "Snow Cat". You can [130]read more about it here. - -HIGH ALTITUDES and LOW TEMPERATURES - -The Super Cat has seen a lot of use in both high altitude and low -temperature environments over the past few years. I regularly receive -email reports from users that have tested the stoves under some fairly -extreme conditions and they largely confirm my own experiences, which -is to say that the Super Cat generally works just fine. - -Increased altitude lowers water boiling temperatures, of course, but -seems to have little effect on the performance of the Super Cat. In -fact, because of the reduced air pressure, alcohol fuel often lights -more easily at higher elevations that it does at sea level. - -Sub-freezing temperatures can make it a bit more difficult to light -most alcohol fuels, however, so it's often useful to maintain a small -"working" bottle of fuel in a coat pocket to keep it warm. Pre-warming -the stove by holding it in your hands before fueling can also help. -Likewise, using a high-methanol content fuel, which has a lower -vaporization temperature than does ethanol, is another way to improve -cold-weather performance, but you'll want to be especially careful with -these fuels since higher methanol content also means higher toxicity. - -The use of either a Fire Bucket windscreen, or of an [131]optional -stand such as those discussed below, can further improve winter -operation. If the Super Cat is in direct contact with very cold ground, -conductive heat losses can sap much of the stove's energy, perhaps even -causing the alcohol to stop boiling, which will probably kill the -flame. Insulating the stove from the ground in some manner will usually -solve this problem. - -Both the Fire Bucket and the optional stands do so by creating an -insulating airspace under the stove, but in really low temperatures, -you might also want to add a bit of home fiberglass insulation to these -air spaces. - -On the other hand, if you're backpacking in these kinds of -temperatures, you'll may also need to regularly melt snow for drinking -water, in which case an alcohol stove is probably not the best choice. -Instead, you're likely better off using a stove that's optimized for -winter use, such as a pressurized white gasoline model, or perhaps a -liquid-feed butane/propane burner like the Coleman Powermax Xtreme. - -LIGHTERS and MATCHES - -There are, of course, many ways to ignite any stove and most -experienced backpackers will usually have already settled upon a -personal favorite. Nonetheless, I thought it might be useful to weigh -in with a few Super Cat-specific comments. I'll also note that there's -a good bit of useful information about fire starters available at the -[132]Backpack Gear Test website. - -Lighters -One of the more popular methods of lighting some kinds of backcountry -stoves is with butane lighters such as those made by Bic, Ronson, -Tokai, Calico and others. Aside from being inexpensive, these lighters -are also lightweight and durable, but there are at least a couple of -issues, especially when used with an alcohol stove like the Super Cat. - -The first, of course, is that these lighters are designed primarily for -use with tobacco products, so your hand ends up very close to the -flame. That's perhaps OK for a cigarette, but not so good for starting -a stove where accumulated flammable vapors can sometimes cause brief -flare-ups during ignition. This design can also present a burn hazard -when the lighter needs to be held horizontally, rather than vertically, -in order to start a stove. - -A second problem is that most of these lighters don't work very well, -or perhaps at all, in cold weather. Most inexpensive lighters are -fueled with regular butane (also known as n-butane), which has a -boiling point of 31°F (-0.5°C). As soon as the air temperature drops -much below freezing, the butane will simply refuse to vaporize and the -lighter will cease to function. I've found this to be the case even if -the lighter is stored in a warm jacket pocket because the moment the -butane gas is exposed to the cold air, it immediately becomes -uncooperative. - -A few lighters, such as those made by Ronson, are fueled with -isobutane, which has the same molecular formula (C[4]H[10]) as -n-butane, but a different structural formula (i.e., it's a butane -"isomer"). The boiling point of isobutane is 11°F (-11.7°C), which -makes its cold weather performance better than n-butane, but even so, -vaporization at temperatures below freezing can still be a bit -sluggish. And when temperatures drop below isobutane's boiling point, -these lighters will likewise cease to work at all. - - [133][Bic-300.jpg] - - [134][Ronson-300.jpg] - -Widely-available Bic lighter * [135](+) - -Ronson lighters use isobutane -for improved cold weather use [136](+) - ___________________________________ - -* Bic and most other inexpensive butane lighters are probably filled -with standard n-butane fuel, but because the ingredients are not listed -on the packaging and because related MSDS documents are either not -available or difficult to obtain (mostly from Chinese sources), I -haven't been able to determine the precise fuel components. Ronson, in -contrast, does make MSDS's for its products [137]readily available. - ___________________________________ - -An alternative is a butane candle-style lighter, where the flame port -is moved away from the hand via a metal extension tube. This design -solves the hand-to-flame proximity problem, but not the cold weather -performance issue. And at weights of 2 to 3 ounces, these kinds of -lighters are also significantly heavier than the ½ ounce or less of -standard models. They are, however, very handy for testing alcohol -stoves in a home or laboratory setting. - - [138][Candle-lighter-300.jpg] - - [139][Solo-lighter-300.jpg] - -Dollar-store candle lighter [140](+) - -Solo brand candle lighter [141](+) - -Most candle-style lighters use [142]piezoelectric ignition where a -small spark is generated at the end of the extension tube in order to -ignite the butane gas. It turns out that even if the lighter's butane -gas won't ignite, this spark alone is sufficient to start some kinds of -stoves, most notably butane/propane canister models. - -Interestingly, I've discovered that the spark alone from some -candle-style lighters can also be used to start a Super Cat. For this -ignition method to work, however, the lighter's spark point must be -located near the tip of the extension tube (rather than at some -distance up the barrel) and the the lighter's tube must usually be -dipped into the alcohol pool for ignition to occur. If lighting the -Super Cat inside a windscreen, this spark-only method still requires -that the lighting hand usually be placed directly above the stove -during the starting process (which makes the user susceptible to burns) -and thus is not recommended. - -If you perform a quick search on the web, you'll find that butane -lighters are offered in a huge variety of styles and prices, with some -supposedly "hardened" for use in outdoor survival situations. All told, -however, I'd suggest passing on such products and sticking with the -venerable wooden match that works in a much broader range of -conditions. - -Wooden Matches -While we tend to think of the common wooden friction match as pretty -low tech these days, it was considered a marvel of engineering when it -was [143]first introduced in 1827. For lighting most backcountry -stoves, however, it remains a great technology. - -Today's wooden matches are generally reliable and safe, allowing the -user to position his or her hand some distance from the flame. They -also perform well under even extremely cold conditions, though -dampness, of course, can sometimes cause problems. The heads of these -matches will likewise usually burn long enough to start most stoves, -even if the wooden splints don't catch fire (as might be the case when -it's very windy). - -There are specialty matches, of course, that are designed for use in -extreme environments and that are usually coated with wax or similar -substances to help make them waterproof. For everyday use with a Super -Cat stove, however, these types of matches are probably overkill and -unnecessarily expensively. They're also harder to light, and because -more force is generally required while striking, I find that they also -break fairly easily (at least that's the case with the Coghlan's -waterproof matches pictured below). - - [144][Matches-storm-proof-300.jpg] - - [145][Matches-waterproof-300.jpg] - -Storm-proof matches from REI [146](+) - -Coghlan's waterproof matches [147](+) - -Instead, I normally use standard wooden matches in both the -strike-anywhere and safety match varieties ("safety matches" require a -compatible striking surface, normally located on the side of the box). -Wooden matches are typically available in two sizes: (1) the larger -"kitchen match" size which is 2.4 inches long and has a beefier splint -and (2) the smaller "penny match" size, which is 1.7 inches long and -has a thinner wooden splint. - - [148][Matches_1609-300.jpg] - - I like both the strike-anywhere and the safety versions - of wooden matches in both the kitchen and penny sizes [149](+) - -Because these matches are not waterproof, it's important to store them -in watertight zipper-bags or hard-sided containers. If you're a -"belt-and-suspenders" kind of backpacker (such as myself), you may also -wish to carry a separate supply of storm-proof matches for starting -emergency campfires under particularly challenging conditions. - -I will also note that a final advantage of wooden matches is that they -can be easily used with Jim's simple wine cork "match extender" -accessory when lighting a Super Cat that's positioned inside a -windscreen. See the "[150]Accessories" section below for more details. - - [151][Entender_1616-450.jpg] - - Using a wine cork match extender [152](+) - __________________________________________________________________ - -Accessories - __________________________________________________________________ - -WINDSCREENS - -As noted in the Super Cat companion article, [153]The Fire Bucket Stove -System: - - "...wind is public enemy #1 for any backpacking stove system, but -because of their low flame velocities, alcohol and tablet-based stoves -are particularly susceptible to the disruptive effects of air movement. -Unprotected from even a slight breeze, these stoves can quickly become -unusable." - -Pretty much sums up the problem. Though I'm discussing this matter in -the "Accessories" section, an effective windscreen is essentially -mandatory if you actually intend to use your Super Cat (or most any -alcohol stove) in the real world. - -Traditional Windscreens -The Internet is replete with easy-to-build windscreen designs that are -usually constructed from some variety of thin sheet metal and populated -with a row of ventilation holes around the bottom. While these designs -are certainly better than nothing, I would contend that there are -better ways to solve the problem. - -I won't address all the issues associated with traditional windscreens -here, since I do so at some length in the [154]Fire Bucket article, but -I will say that screen ventilation issues probably create the most -compelling performance problems. - -As I also note in the Fire Bucket article: - -"...Unless fairly large in size, the ventilation holes used in most of -these designs can offer a fair amount of resistance to air entering the -windscreen, which can starve a flame for oxygen. If the holes are large -enough to permit the free flow of air, then they probably also -contribute to internal air turbulence when the wind blows." - -[155]The KiteScreen -One alternative approach to solving some of these problems, discussed -in my [156]KiteScreen article, is a fabric or film-based screen that's -anchored to the ground and that's large enough to protect the entire -cooking setup. This design works particularly well for top-mounted -canister stoves that are otherwise difficult to safely shield from the -wind. - - [157][Kite_4697-300.jpg] - - [158][Kite_1184-300.jpg] - -Tyvek-based KiteScreen [159](+) - -KiteScreen made from -Reynolds oven bags [160](+) - -[161]The Fire Bucket Stove System -Another approach, however, is the Fire Bucket itself. The Fire Bucket -starts with a traditional windscreen design, but then incorporates two -key changes that significantly improve wind protection for the Super -Cat (or most any other alcohol stove). - -The first change is to replace the traditional row of ventilation holes -with a single, large ventilation port that's situated on the downwind -side of the barrier. The second involves elevating the stove onto an -open-grate burn platform so that it's much less affected by the supply -air flowing into the screen. - -The synergy of these two changes also allows for a design that can -serve not only as a windscreen, but also as an efficient stand-alone -stove for burning wood and solid fuel tablets all at a weight (in its -lightest implementations) of about two ounces. It likewise permits the -addition of a series of accessories (like the "wind shade") that can -further enhance its functionality. The photos below show one of my -favorite versions of the Fire Bucket that can be collapsed for -transport on the trail. - -The Super Cat and Fire Bucket together form an efficient, lightweight, -integrated stove system that's easy to build and fun to use. For more -information, please see the [162]Fire Bucket article. - - - [163][Stove+Bucket2_1542-300.jpg] - - [164][Jim3_1340-300.jpg] - -Fire Bucket windscreen with -Super Cat alcohol stove [165](+) - -Top view shows burn platform [166](+) - - [167][Jim4_1347-300.jpg] - - [168][Shade_1409-300.jpg] - -Disassembled for transport [169](+) - -Shown with optional wind shade [170](+) - - -OPTIONAL STANDS - -If you decide to build a Fire Bucket, you normally won't need a -separate stand for the Super Cat, since the Fire Bucket includes a -built-in, elevated stove platform. If you want to use a traditional -windscreen, however, or if you'd like to build a handy test platform, -an optional stand can make a lot of sense. - -In April of 2005, I published plans for a stand that a fair number of -Super Cat users constructed, but a year later, came up a design that I -thought was superior. Below are summarized some of the advantages of -using both a separate stand in general, and of the second-generation -design in particular. - -Why Build a Separate Stand? - * The Super Cat just might be an example of a piece of ultralight - backpacking gear that's actually a little too light. A fair amount - of caution must be exercised when using the stove on uneven ground - or in windy environments, since its miniscule weight (0.2 oz) makes - it prone to tipping or blowing over under those conditions. The - small incremental weight of a stand by itself can help stabilize - the stove. - * The stand creates a wider base with fewer ground contact points, - improving stability. - * The second-generation design allows the stove to be further - stabilized by staking it to the ground. I often insert a pair of - slim tent stakes through the two holes in the base of the stand, - then push them into the ground. This arrangement virtually - eliminates any possibility of the stove tipping or blowing over. - * The docking socket feature allows different stoves to be used with - the same stand since there's no permanent connection required - between the two. The socket is tight enough, however, to hold the - stove very securely. - * The stand protects the bottom of the stove from damage. If the - stove alone, for example, is placed on a gravel surface, the weight - of a pot filled with water can sometimes push the bottom's soft - aluminum into the sharp edges of stones, causing dents and possibly - even punctures. The stand eliminates this hazard. - * The airspace trapped under the stand base serves to insulate the - stove from cold ground. Doing so solves pretty much eliminates the - conductive heat losses to the ground that can otherwise ruin the - performance of an alcohol stove when used in cold weather. For use - at really low temperatures, it's also possible to fill the base - with fiberglass insulation for even better performance. - * This same airspace also protects the surface under the Super Cat - from the heat that's produced by the stove. I can now use the stove - directly on my workbench without having to worry about cooking the - surface. The airspace also protects the vegetation under the stove - when used on the trail. - * The base allows the effective use of the "snuffer cup" that's - described below. The snuffer cup seals well against the uniform - surface of the base, permitting the stove to be easily and reliably - extinguished at will. A great fuel-saving and safety feature. - * And finally, the top of the stand base can serve as a priming pan - for the stove. Adding a few drops of alcohol primer to the base - just outside the wall of the stove helps the stove come up to - operating temperature faster and also makes it easier to light the - stove, especially in cold weather. - Now, rather than having to reach over top edge of the stove with - your match or lighter to ignite the alcohol fuel, it's possible to - simply light the primer outside the stove (the flame quickly - spreads inside). The outer ridges that are stamped into the base - can's bottom conveniently keep the priming fuel from spilling over - the edges. - -The Fire Bucket, with its built-in, elevated stove platform, provides -most of the same advantages as a separate stand, especially when used -with its optional stove holder. - -Nonetheless, if you'd like to build a stand, plans for both the first -and second-generation models are included in separate documents, -accessible using the links below. By the way, a note for stand fans: -the first-generation plans include links to photos of several discarded -design ideas that you might find interesting. - - [171][Stand2_0060-300.jpg] - - [172][Stand1_4400_300.jpg] - -Second-generation stand [173](+) - -[174]Click here for build instructions - -(Recommended version) - -First-generation stand [175](+) - -[176]Click here for build instructions - - -THE SNUFFER CUP - -If you happen to over-fuel the Super Cat, it's very nice to be able to -extinguish the flame before the alcohol has burned itself out. You -might want to stop the stove to in order to recover unburned fuel, or -maybe for emergency reasons. - -As discussed above, if you have an empty cook pot handy, you might be -able to invert it over the stove to deprive it of oxygen, though -because of the relatively large volume of air inside, that process -could take a while. Alternatively, you can build a dedicated, -low-volume vessel that can quickly smother the flame. I call this -accessory a "snuffer cup". - -In either case, the vessel you use to smother the Super Cat must form a -reasonably airtight seal against the surface upon which the stove is -positioned. If air can flow under the edges of the smother vessel, it -won't work very well, since oxygen will continue to fuel the flame. For -this reason, the snuffer cup's mating surface is as important as the -cup itself. - -Selecting a Can -Any metal can that's slightly larger than the Super Cat itself will -usually work as a snuffer cup, though I've found that an empty 5½ or -6 ounce aluminum pet food can is about perfect for the task. If you -also build the second-generation stand discussed above, it's probably -best to use the same brand of can for both projects to ensure an -optimal fit between the two. - -Most of the pet food cans in this size range that I've examined appear -to be almost identical in dimensions, though the bottom ridge pattern -can vary from brand-to-brand. Any of these cans should be tall enough -to cover a Super Cat that's made from the most common of the 3 ounce -can sizes without air gaps. - - [177][Snuffer-cans_1544-450.jpg] - - Snuffer cup aluminum can possibilities [178](+) - Note that the 6 ounce Iams can (L) - is slightly taller than another popular size - -However, if you dock the stove with a stand (which raises the height a -bit), or build the Super Cat from a slightly taller can, you'll -probably also need a taller snuffer cup. - -One option is just to search for a can with sufficient "head room". -Among the pet food products inspected, I've noticed that the 5½ ounce -Mighty Dog cans are a bit taller than most. Likewise, the 6 ounce size -of Iams cat food (which may now be available only in the veterinary -formulas) is about 1/8 inch taller than similar products. - -Another option is to bend the bottom of the can outward a little by -pressing firmly in the middle or alternatively, by working a blunt -metal tool (such as a socket wrench extender) around the bottom's -ridges in order to flatten and extend them. - -Adding a Knob -Though not mandatory, a knob positioned at the top of the snuffer cup -will make the cup easier to handle and can also help keep your fingers -from being burned when the cup is lowered onto a flaming stove. - -A small wooden knob can be purchased from a hardware store or easily -constructed from portion of a wine cork (either plastic or natural) or -a scrap of wood. The knob can then be attached to the snuffer cup by -first punching a small hole in the middle of the bottom surface of the -cup along with a similar hole in the middle of the bottom of the knob. -A small diameter sheet metal screw, perhaps ½ inch long, can then be -used to join the two. - - [179][knob1_1546-300.jpg] - - [180][knob2_1548-300.jpg] - -This small wooden knob was -found at Home Depot [181](+) - -This knob was made -from a wine cork [182](+) - -Weights -A 5½ or 6 ounce aluminum pet food can will typically weigh about -½ ounce, while a comparably-sized steel can will probably weigh about -1½ ounces. A knob and screw will add about ¼ ounce to either for a -total of ¾ ounce for aluminum and 1¾ ounces for steel. - -Fuel Recovery -As noted above, a bonus use for the snuffer cup is to assist in the -recovery of unburned fuel. Because of the Super Cat's side vent holes, -it's difficult to pour unspent fuel directly from the stove back into a -fuel bottle without spillage. Instead, you can quickly dump remaining -the fuel from the stove into the snuffer cup first, and then pour that -fuel from the cup into the bottle. - -A small notch that's filed or bent into the inside rim of the snuffer -cup, as shown in the photo below, can facilitate the pouring process -without compromising the cup's air seal. Thanks to Ernie Priestley from -Seattle for this great idea. - - [183][Notch_1551-450-2.jpg] - - A small notch filed into the inside rim - of a snuffer cup can assist with fuel recovery [184](+) - -Using the Snuffer Cup with a Fire Bucket (or other Windscreen) -You can use a snuffer cup to stop a stove that's operating inside a -windscreen such as the Fire Bucket, but you'll need to modify both the -cup and your technique. That's because lowering a snuffer cup into -place holding its top-mounted knob (while the stove's flames are raging -inside the bucket) is difficult to do without burns. - -One solution is to remove the knob, then pass a thin hook or nail-type -tent stake from inside up through the center hole to create a "handle" -for the snuffer cup. Also, when lowering the cup into place over the -Super Cat, it helps to tilt the cup towards the back of the windscreen -as it descends in order to direct the flames away from you hand. - -For more information about these modifications (including photos), -please see the [185]snuffer cup section of the Fire Bucket article. - -JIM'S MATCH EXTENDER - -If you'd like to increase the safety distance between your hand and the -Super Cat when lighting the stove with a wooden match, you can make a -simple extender from an ordinary wine cork (either a natural or a -plastic cork works fine). Such an extender is particularly useful when -it's necessary to reach over the top edge of a windscreen in order to -light the stove. Because alcohol vapors can often accumulate inside the -walls of a windscreen prior to ignition, it's best to keep your hand -outside the screen in case there's a flare-up. - -You can construct a match extender by boring a small hole into each end -of the cork using an awl or a nail. These holes, which need be only -about ½ inch deep, can then be used to hold a wooden match at one end, -and some sort of handle at the other. Most corks weigh less than ¼ -ounce, and if you're a gram counter, you can even cut the cork in half -to further reduce the weight. - -The handle I generally prefer is a thin titanium tent stake (as shown -below), though a slim wooden branch, a Fire Bucket pot support, another -wooden match (preferably spent), Jim's [186]bagel toaster, or even a -length of coat hanger wire all work well. - - [187][Extender2_1612-300.jpg] - - [188][Extender3_1614-300.jpg] - -Using a spent match -as a short handle [189](+) - -A thin titanium tent stake -makes a longer handle [190](+) - - [191][Extender1_1611-300.jpg] - - [192][Extender4_1616-300.jpg] - -A small hole is bored into -each end of the cork [193](+) - -Positioning the -match extender [194](+) - -To use the extender, first insert the handle in one end of the cork, -and an unburned match in the other. Then strike the match with the -extender in place and move the match towards the stove while holding -the handle end. - -OTHER ACCESSORIES and MODIFICATIONS - -Fiberglass Wicking -One modification that I've tried is lining the bottom of the Super Cat -stove with a small amount of fiberglass insulation, held in place by a -patch of aluminum screen. Some other alcohol stove designs use -fiberglass as a wicking agent, so I was curious to see if there was any -effect on performance. About the only impact it had was to slow the -stove down a bit, with boil and total burn times both increasing by -about 25%. The fiberglass did help keep the alcohol fuel from sloshing -around quite as much (depended on fill level), but I ultimately -concluded that the addition of fiberglass otherwise had little value. - -Priming Cord -Some stove builders, such as Jason Klass, have done a good bit of -experimentation with the Super Cat and its derivatives. One idea that -Jason has promoted is wrapping a length of [195]thin Kevlar cord around -the base of the Super Cat a few times to absorb a bit of alcohol -priming fuel. This idea, was I think, adapted from a design originated -by Tinny at [196]minibulldesign.com. - -This cord, which serves as an alternative to a priming pan, allows the -stove to be ignited from the outside, while likewise reducing priming -time. The cord would interfere with inserting the Super Cat into a -holder or stand equipped with a docking socket, but if you like the -idea, you could probably wrap the cord around the docking socket -instead. Jason has developed a number of other innovative stove and -windscreen concepts that can be [197]viewed on his website. - -Priming Cap and Flame Column Compactor -Partially covering the top opening of the Super Cat with a metal disk -that includes a center hole about 1" in diameter can reduce priming -time from 25 or 30 seconds to perhaps 15 seconds or less without -requiring (as most other priming methods do) any additional fuel. - -This method works by absorbing more of the heat that's produced by the -stove just after ignition and feeding it back into the alcohol pool to -accelerate the fuel boiling process. - -There are at least a couple of ways to restrict the top opening. One is -to simply cut a disk from aluminum of the appropriate size, make a -center hole, then rest the disk on top of the stove. Unless the disk is -secured, however, it can sometimes "jump" off the stove with a pop when -the accumulated alcohol fumes are ignited. - -An alternative is to glue the disk permanently into position using a -high-temperature epoxy such as [198]J-B Weld. I've tried this method -myself, but found that even though the adhesive is rated for use up to -500°F, it tends to eventually fail with use. Nonetheless, it usually -works well enough for as long as it lasts. - -In either case, it's important that the top surface of the disk not -extend above the upper lip of the Super Cat, otherwise, the stove might -leak air around the rim and fail to pressurize. - -The photos below show two disks cut from the bottoms of 3 ounce pet -food cans. Either round or rectangular holes work fine, though -rectangular holes are easier to make (the one below was carefully cut -with a box opening knife). A metal file can be used after cutting to -clean up the edges. - -When in use, the cook pot can be lowered onto the Super Cat as usual -after the priming process (which should now require less time) is -complete. - - [199][Cap1_1561-300.jpg] - - [200][Cap2_1564-300.jpg] - -These priming caps were made -from the bottoms of -3 ounce pet food cans [201](+) - -Priming cap in position -atop the Super Cat [202](+) - -Another interesting method, developed by [203]Zen Seeker, requires the -use of an unopened 3 ounce aluminum can. Rather than opening the can -from the top as usual, the user first cuts a hole about one inch in -diameter in the bottom center of the can, then removes the can's -contents through this hole. - -The result is an "upside-down-Super Cat" whose side vent holes must be -drilled, rather than punched, since most punches can't work through the -restricted top opening. The principal disadvantage of this design is -that the inverted Super Cat now won't fit into the docking socket used -for the stands discussed above, nor into the optional stove holder that -can keep the Super Cat centered inside of a Fire Bucket windscreen. - -On the plus side, concentrating the open Super Cat flame into a more -compact column allows the stove to be used more effectively in what I -call "open burn mode". That is, positioning the cook pot above the -stove on some manner of pot stand, rather than directly on top of the -stove as one normally would. Raising the pot in this way offers another -way to reduce heat output that might be useful for simmering. - -The "Swivel Cat" -This final accessory is not actually directly related to the Super Cat -itself, but rather, is a different kind of alcohol stove altogether. - -Called the "Swivel Cat" for reasons that are probably apparent from the -photos below, it offers an alternative way to cook at reduced heat -levels. The idea is similar to that behind the "Simmer Cat" discussed -above, except that it allows heat output to be adjusted in real time -while the stove is operating. - -The Swivel Cat is not very hot-burning, though, so it's really only -useful for simmering. And unlike the Super Cat or Simmer Cat, it -doesn't include a built-in pot stand, so it requires some type of -independent support (it works great in the Fire Bucket, however). - -The Swivel Cat is made from the same kind of 3 ounce aluminum can used -for the Super Cat, except there are no vent holes in the sides. -Instead, a circular disk, slightly larger than the top opening of the -can, needs to be cut from aluminum flashing and attached as a swiveling -lid. - -This lid connects to the stove via a small "L" bracket, which is also -cut from aluminum flashing and is installed at the top edge of the -stove as shown below. The lid attaches to the bracket using a single, -loosely fitting rivet or machine screw connection. It also needs to be -installed in such a way that it mates fairly closely with the top rim -of the stove. - - [204][Swivel1_1566-300.jpg] [205][Swivel2_1567-300.jpg] - -Low simmer lid position [206](+) - -Moderate simmer position [207](+) - [208][Swivel3_1568-300.jpg] [209][Swivel4_1569-300.jpg] - -Fully-opened position reveals -the "L" bracket inside [210](+) - -Fully-closed position [211](+) -(Note the "L" bracket rivets on rear wall) - -The Swivel Cat uses normal Super Cat fuels and is ignited over the top -rim. Once it's burning robustly, a pot can be positioned at the desired -height above the stove on separate supports. Assuming the stove is -encased in a windscreen, heat output can be increased or decreased as -follows: - * First, remove the cook pot from its supports. Then, using the end - of a metal tent stake, rotate the swiveling disk so that it covers - either more or less of the top stove opening. The more of the - opening the lid covers, the lower the heat output will be. In fact, - if the disk is closed all the way, the flame will be extinguished. - * Once the desired heat level has been obtained, the pot can be - returned to the cooking position above the stove. - -Because there are no ventilation holes, the Swivel Cat will hold almost -2½ fluid ounces of fuel. If filled to capacity and operated at a low -simmer, the Swivel Cat will burn for a very long time before it needs -to be replenished. - __________________________________________________________________ - -Resources - __________________________________________________________________ - -FURTHER READING - -While the Internet abounds with information about alcohol stoves, there -are three online resources that might be of particular value to you. - 1. [212]Backpackinglight.com describes itself as "The Magazine of - Lightweight Hiking and Backcountry Travel". The staff at BPL, - especially Will Rietveld and Roger Caffin--who have prepared most - of the stove-related articles--have consistently conducted the most - thoughtful, well-balanced and scholarly research that I've seen to - date in the world of outdoor journalism. - Their high-quality, in-depth analyses of a wide range of - backcountry-related subjects has made my $24.99 annual subscription - fee seem like a great bargain (by the way, I have no affiliation - with BPL other than as a standard subscriber). - 2. Jason Klass is a fellow backpacker who took an early interest in - the Super Cat stove and has developed a number of his own - modifications and enhancements. I'd encourage you to visit his - [213]nicely-designed website. - 3. Zen Seeker has volunteered a great deal of time and energy to - develop one of the Internet's "go-to" sites for reliable - information about backpacking stoves and related subjects. The - [214]Zen Stoves website is cited multiple times above and is a - terrific resource for any do-it-yourself stove builder. - -USER FEEDBACK - -Ever since placing its design concepts into the public domain in 2005, -I've considered the Super Cat to be a work in progress and have -actively encouraged users to develop their own modifications and -improvements. - -Over the years, great numbers of Super Cat enthusiasts have been -generous enough to provide feedback, primarily in the form of emails -and online bulletin board postings. Many of these insights remain -accessible through the Base Camp feedback forum (link below). - -My hope now is that this updated article, along with the concurrent -introduction of the companion Fire Bucket system, will stimulate a -renewed wave of user-based development. - -If you take an interest in the Super Cat, please report back through -the feedback forum on your experiences and recommendations. This "open -source collaboration" (to borrow a phase from the software industry) -will strengthen the design for all of us. - -[215]You can submit or read comments about this article here. - -CONTACT ME - -If you'd like to contact me directly, [216]please do so here. - -[217]Top - -[218]Home - - Copyright © 2005 - 2010 James E. Wood. 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