In a previous article, I discussed using alcohol stoves for post-SHTF cooking. The advantages of an alcohol stove are several. They are compact and store easily. The fuel is relatively safe and readily available. You don’t have the smoke of cooking over a wood fire. And they are inexpensive. However, I was not satisfied with the two models of alcohol stove that I purchased and tested. Most alcohol stoves are designed for camping. They are small, lightweight, hold only an ounce or two of alcohol, and cannot cook for more than a half hour or so. And even the stoves that claim to have a ‘simmer setting’ are not very adjustable. They run on high, or on low (and sometimes the difference between the two settings is not much). But I don’t want a stove for camping. What I’m looking for is an alcohol stove for prepping.
Since I could not find what I wanted among the plethora of small alcohol stoves for camping, I designed my own alcohol stove. It is a little larger and heavier, but not much more expensive, than the typical camping alcohol stove. It holds plenty of alcohol and has an easy-to-adjust flame. With 4 ounces of 91% isopropyl alcohol, it will cook on the high setting for one full hour. With 8 ounces of 91% isopropyl alcohol, it will cook on the high setting for two full hours. Of course, if you adjust the flame to one of the lower settings, it will cook for even longer.
This new alcohol stove design does not use alcohol fumes under pressure, as the penny alcohol stove and other designs do. Instead, carbon felt is used to hold the alcohol, and the heat is from an open flame. I consider this design feature to be safer. The carbon felt absorbs the alcohol, and keeps it from spilling. And gas under pressure seems inherently more dangerous to me.
The stove is designed to use 91% isopropyl alcohol. It will work with 70% isopropyl alcohol, but it does not produce as much heat. The 91% isopropyl alcohol has 30% more fuel than the 70% does (0.70 * 1.30 = 0.91). The isopropyl alcohol has the disadvantage of producing soot on the bottom of the pan that you use for cooking. But it has several advantages: more heat per unit volume of alcohol, the flame is easier to see, the fuel is easy to find in almost any drug store or supermarket, and is inexpensive. Isopropyl alcohol is used on the skin as rubbing alcohol, in homes, hospitals, and doctor’s offices. It is toxic to drink, but otherwise relatively safe.
I strongly recommend against using methyl alcohol in this or any other alcohol stove. Methyl alcohol is highly toxic and can be absorbed through the skin. It is also difficult to see a methyl alcohol flame in the daytime. You are getting less heat with methyl alcohol because it is a lighter fuel. Also, it is less readily available and more expensive. This new alcohol stove design is not designed for use with methyl alcohol.
Before I describe how to make this stove, a few words of caution are in order. Using any alcohol stove is inherently dangerous because you are cooking with an open flame. Keep away from all children, irresponsible teens, responsible teens, and irresponsible adults. Do not use an alcohol stove in an enclosed space. Some carbon monoxide may be given off by any alcohol stove. Use only with ample ventilation. NEVER use any fuel for an alcohol stove other than ethyl alcohol or isopropyl alcohol. Use of methyl alcohol is not recommended.
Use of gasoline, lighter fluid, or any other petroleum-based fuel is stupid and extremely dangerous! NEVER attempt to put out a gasoline or other petroleum-based fire with water. Attempting to do so is dangerous and will spread the fire.
Keep a pint or two of water handy in case the alcohol spills and catches fire. Yes, alcohol fires can be put out with water. Also, keep a spray bottle of plain water handy. You can use the spray bottle to quickly cool down the stove or the pot-stand after you are done cooking. You can also use the spray bottle of water to put out an alcohol fire.
This alcohol stove design is experimental. If you decide to build and use this stove, you do so at your own risk. Use your own good judgment, and take responsibility for your own decisions. You’ve been warned.
Three-Flame Alcohol Stove
Take one empty 12-oz. tuna can. This is the larger and less-common size of canned tuna. Empty the can, remove the label, wash and dry.
Cut strips of carbon felt 1.75″ wide. The strips should be wide enough to almost reach to the top of the can when placed inside. The total length of all the strips should be about 6 feet.
I bought carbon felt from FastoolNow, through Amazon.com: Steiner Carbonized Fiber Mini Blanket — 18 in. x 18 in. Carbon fiber (or “felt”) is a fabric that is impervious to fire and heat: “Protects from sparks, spatter and slag. Soft, lightweight with excellent flexibility. Continuous operating temperature to 1,800° F, intermittent to 3,000° F”. This material is commonly used in alcohol stoves. It will not catch fire or emit smoke at normal alcohol flame temperatures. It absorbs the alcohol, and also acts as a wick, to bring the alcohol to the surface to continuously feed the flame.
Coil the strips and place in the tuna can.
Buy a three-pack of 5-inch aluminum pie pans. You will need all three. Take each pie pan and press-fit it to the top of the tuna can. The bottom of the pie pan is a little smaller than the tuna can. But if you press it over the can, you can mold the bottom to fit the can well. Set aside one press-fit pan as a cover. This cover can be used to put out the stove by smothering the flame.
Take another pan and cut out three of the sections on the bottom of the pan. There are 8 sections marked with ridges on the pan. Cut sections 1, 4, and 6. This leaves the holes staggered unevenly. That is what you want, so that when you turn it, you can expose three, two, or one of the openings. Make sure to cut each hole a little smaller than the markings for that section, so that the top pie pan can be turned and all the holes will be sure to be covered.
Cut another pie pan in the same way, with the same three openings.
Now take one of the two pans and cut off the rim. Then put it over the tuna can containing the carbon felt, and press fit the sides of the pan to the can.
Set the other pan over the first, and turn it so that all three holes are lined up. This is the “high” setting for the stove. You can turn the top pie pan a little, so that all three openings are about half-size. You can also turn the top pan so that only two or only one opening is lined up. Each setting — one, two, or three openings — can be tuned to a half-open setting. The result is six different settings for the stove.
You can also turn the top pan so that all openings are closed, to turn off the stove. If the stove is very hot, some alcohol fumes may leak out and continue to produce a flame. Use the third pie pan, the one without any holes in it, to cover the stove and smother any flame.
I use 4 small wooden clothes pins around the top pan, so that the pie pan can be turned, even after it heats up. These clothes pins are wood, not plastic, and are 1.25″ inches length. I purchased these at Walmart, in the section with paper clips, staplers, and office supplies. They also had smaller clothes pins (in the crafts section) that turned out to be too small.
Here is a YouTube video, Making a Three-Flame Alcohol Stove, showing how the stove is put together. I pour the alcohol into the stove before putting both pie pans on top of the can. The design is relatively simple and easy to put together and take apart. And here are a couple of videos of the stove in action: Simple Alcohol Stove using Carbon Felt and Three-Flame Alcohol Stove.
Two-Flame Alcohol Stove
An alternate design of the same type of stove uses only two openings. This design allows for two larger flames, instead of three flames. It seems to produce more heat to cook faster/hotter, but it is less adjustable. You can still turn the top pie pan to restrict both openings, and reduce the heat. You can also turn it so that both openings are covered to turn off the stove. Again, you may need to place the third pie pan on top to put out the flame entirely.
For the two-flame alcohol stove, follow the instructions for the Three-Flame Alcohol Stove, but cut only two openings. Each opening should occupy a little less than two of the 8 pie pan sections (about 1/4 of the bottom of the pan for each opening). In this case, the openings are not staggered; they are opposite one another.
Watch the YouTube video of this stove in action: Two-Flame Alcohol Stove.
For the pot stand, I purchased a cold beverage jar stand at Walmart for 10 bucks. (I can’t seem to find it on their website.) It holds the pan a few inches above the stove, and it has sides that prevent the pan from slipping off of the stand. I did not find it necessary to make a wind screen for use with this stove. The pans that I would use for post-SHTF cooking are not the very small and light pots used in camping. I would use a regular 4-quart or so size pan.
I tested the two-flame alcohol stove, to see how quickly it can boil water. Using a 4-quart pan, it took 12 minutes to bring 2 cups of water (16 oz) to a full rolling boil (212 degrees F measured by a digital thermometer). Various small camping stoves claim to be able to bring the same amount of water to a boil quicker. But they are not using full-sized cookware, and they might only be bringing their water to the point of having some bubbles on the bottom of the pan (~175 degrees F). In any case, these stove designs are not optimized to boil water as fast as possible, but rather to have a highly adjustable stove for cooking all kinds of food.