Cat/Tuna Can Stove
Price: About $6
Weight (Manufacturer): 1.6oz
Weight (tested): 3.5oz
URL: Hiking Web Site
Instructions to build: Cat Stove
If you don't want to build one, order one.
I had been looking for a low weight backpacking stove to replace the Peak 1. The Peak 1 is a great stove - very adjustable flame, heats quickly, and fairly easy to use. But it is heavy and takes up a lot of space. I was looking at another gas stove - the Primus Liqui-fuel, and the Sierra Zip stove. Wasn't sure which way to go. The Primus is a white gas stove that needs priming, pumping, assembly, and maintenance; and the Zip needs batteries, weighs a bit, and may be illegal in certain areas because it is basically an open fire.
Then I was looking on the Lightweight backpacker and was reading about light weight home made alcohol stoves. Sounded low tech and like bad performers. But since they were cheap to play with and I had some time to experiment, I decided to build one. I'm very glad I did!
After reading around I decided to go with the Cat food Can stove. I don't have a cat, but had some tuna - so just opened a couple of cans and made the stove. I tried it out and WOW!
I won't go into a lot of building details, they are here: Cat Can Stove. What I'll go into is some modifications and performance findings. First of all, my stove weighs 1.5oz with the simmer ring option. Cat food cans must weigh less than tuna cans. My wind screen weighs an ounce as well, my aluminum is either heavier, or my screen is bigger because of pot size, it weighs 1oz. I couldn't find the welder's wire in the description, but made a low tech solution out of a coat hanger, it and the pot holder (a piece of cotton cloth) weigh an additional ounce. Total weight is 3.5oz - twice the listed weight of the cat can stove, but I'm happy. Additionally I use a Mt. Dew 20oz bottle as a fuel bottle - 1oz in weight. I wrapped 8 wraps of duct tape around it (1oz) for general tape storage and gave it a red cap from a coke bottle. 2 caps full = .5oz. I got my insulation from a construction site for free, but steel wool also works, it just starts to rust and degrade after a few uses.
Breakfast. Use 1 oz alcohol to heat 16oz water. Then either have 2 packets grits and 1 coffee, or 2 cups coffee and have cold breakfast.
Lunch. Never cooked lunch anyway, but could do .5oz alcohol to boil 16 oz water or .25 oz alcohol for 8oz. Good for ramen, or a cup of tea.
Dinner. When cooking dishes like ramen - put the noodles in the water, then heat using .5oz alcohol until done. If doing a more complex dish that require simmering there are two methods depending on the dish:
1. Put dish in the water and boil using .5oz alcohol. When flame burns out, put on ring and add .5oz-1oz and simmer until done. Must stir during simmer or food may burn to pot. Instructions for food that must simmer 10-15 minutes do well using this.
2. Put dish in the water and use simmer ring with 1-1.5oz alcohol. After about 7 minutes you must stir during simmer or food may burn to pot. Instructions for food that must simmer 20-25 minutes do well using this method.
Fuel needs should be 1-2 oz per day. My 20 oz bottle (actually holds about 22oz) will last 10-20 days! It helps to pre-soak your food about 5 minutes before cooking.
1. It can't break! Unlike gas stoves, there is absolutely no moving parts. And if something did break, it can be repaired using simple tools like scissors, a church key, and a knife.
2. It doesn't require tending. Put in the alcohol and light. then the dish usually cooks itself while you work on camp. Some dishes require stirring, but they would no matter what stove you use.
3. It's very very small and easy to pack. After using it it was cool enough to touch without and real heat within 3 minutes. I can fit it inside my pots, and the stand fits outside the bag. I put the windscreen in my sleeping pad.
4. It's quiet and safe. It doesn't sound like a jet engine (like some stoves). The fuel isn't explosive and can be mailed or carried on an airplane. The fuel can be gotten almost anywhere (32oz bottle at Wal-Mart is $2.95). Also the flames are huge. Some alcohol stoves are hard to tell when lit, this one has flames large enough to see because it burns very efficiently.
5. It's light. Stove - 1.5oz, stand and potholder - 1oz, wind screen - 1oz, fuel bottle - 1oz, and fuel (20oz @ .8 per oz) - 16oz. Total weight is 20.5 oz. This is lighter than the weight of my Peak 1 empty, or an empty MSR Dragonfly with 22oz bottle.
This stove is great. It has everything I want in a stove. I probably wouldn't take it on a super cold winter trip, but when backpacking in the east, in three seasons, and cooking small dishes, why carry a stove that weighs more than the meal you want to cook? Go get the parts and build one!
Made a new stove using cat food cans, only changed the weight a very small amount. I also made a new wind screen and a pot stand from hardware cloth. Now the whole stove weight is down to about 2.5oz and boils water even faster if you can believe it!
While testing the simmer ability I have never been completely satisfied with the simmer ability of this stove, so I did some experiments using different stove models and designs. I found the following:
1. Air flow affects how well the alcohol burns. Better air flow makes the alcohol burn completely, less air flow can make the alcohol boil then evaporate. If you smell alcohol while the stove is lit, there isn't enough air flow. Air flow is also important at the top near the pot. Less airflow near the pot smothers the flame.
2. Pot distance is critical to heat transfer and flame operation. If the pot is too far away, then the heat doesn't transfer well to the pot and water. If the pot is too close, the flame smothers out or doesn't reach full potential. Different models depend on pot distance in different ways. Pot distance for the cat can stove is best at about 7/8" above the burner.
3. Burner area also is important. Their is a ratio between air flow and burner area is interlinked. I haven't exactly figured out what the math is, but it basically works like this: more air and less surface area, the flame and alcohol will try to escape out the burner jacket and alcohol will evaporate without burning; more surface area and less air flow produces the same results.
4. Wind screen cannot be too tight against the pot or it restricts air flow, but it shouldn't have too much of a gap or heat will be lost. It also does not need to go higher than the handle like my previous screen. Best results were with about a 1/8" - 1/4" gap around the stove.
For better boil times I added two more holes to the jacket - total of 8, and four more to the inner burner - total of 8. I also made the wind screen shorter and tighter to the pot.
To make a good simmer - both need to be changed. My solution was to trim down the simmer ring, and ad a simmer cover that reduces burner surface area. To change the simmer level, the cook pushes out from the bottom for more surface area, or in from the top for less surface area.
I started working on a Cat Stove to send in to Backpacker Magazine for the Backpacker Magazine Home-Brewed Stove Competition. I made the standard stove with a couple of slight modifications to get the weight down to 1.9 ounces. The modifications were to cut out a few of squares from the hardware cloth stand, and making the wind screen a little shorter. But while I was working on the stove, I remembered a home made stove from Wings, and got the idea to try a new way to save weight - a pot cozy.
Here is the idea. Make an insulated cozy for the pot using some left over foam pad from trimming a sleeping pad. Instead of using more fuel to simmer, insulate the food in the pot to allow it to simmer from the heat already generated. This would reduce the amount of fuel carried, make a smaller bottle possible, and reduce the stove parts. All of this will save weight
Linguini had shown using one on his web site, and I had read it months ago, but his cozy weighed about 3-4 ounces. I could simmer about 6-9 times on the same amount of fuel. So I didn't really put much effort into it.
Fortunately I have an old Army sleeping mat I trimmed down and saved the extra. So I cut it into the right shape, then taped it together. It weighed 1.5 ounces, heavier than I wanted. I removed all the tape and weighed it, only .8 ounces, wow duct tape is heavy. I already carry a binder clip to make a headlamp, clothes pin, etc. out of, this worked great for holding the ring of the cozy closed without extra weight. The bottom is held in place by tension, and does fine as long as I lift the pot from the bottom or use the handle while in the cozy.
Now to test it. I pick one of the hardest backpacking meals I could find around the house, medium grain whole rice. This must be boiled, then must simmer 20 minutes. So I boil 1 cup rice and two cups water with .5 ounces fuel, then put the pot in the cozy. After 20 minutes in the cozy the rice and water is very hot, but not finished cooking. 30 minutes later the rice is done, and it is still too hot to eat! The only problem was too much water, not enough boiled out because I kept the pot covered. Next time I'll use less water.
Now I calculated the weight savings:
1. Less fuel needed per day. I use 1/2 ounce at breakfast, 1/2 at dinner, plus an extra 1/2 for tea, more food, etc. I now need only 1.5 ounces per day instead of 2 ounces. Savings are 1/2 ounce per day, or 3 ounces a week average. 1/2 ounce fuel weighs .4 ounces.
2. Smaller fuel bottle. I used to carry a 20 ounce bottle at .9 ounces, now I can use a 12 ounce bottle at .6. Only a .3 ounce saving, but I'll carry a smaller maximum amount.
3. Less stove parts. This only saved me .1 ounces. Again, very small.
Total, .8 ounces for one day fuel and parts - dead even. Each day I'm out longer adds up another .4 ounces saved. So in on a week long backpacking trip I would save 2 ounces. Not a great weight savings, but it does save weight.
Other advantages. When I put the pot in the cozy, I can now hold a scalding hot dish, and I can keep it warm for hours. The smaller fuel bottle takes up less space.
Disadvantages. More bulk. The cozy takes up some more internal backpack space when I store it around the pot inside the pot bag.
Conclusion. If space is premium in your pack, then maybe sticking to the simmer parts for your stove may be the solution. Or, you may find a way to roll up the cozy inside a sleeping pad. If your looking for a way to loose another couple of ounces, then try it.