View Full Version : alcohol stove issues
I made a nice looking alcohol stove out of two pop cans, it has inner wall with holes around top edge to allow gasses to burn through, it work great looks like a gas stove top when the flames incircle top of can. My issue was I couldn't get it to ever get 1 3/4 cups of water to ever get to fast boil, and it took about 10-12 minutes to get little bubbles. I didn't know if I was doing something wrong or if my aluminum pot from REI is hurting results. I really think my stove is built correctly, but results don't look like youtube results?
Another Kevin
10-27-2015, 14:24
You've probably made too small holes, or too few. Also, make sure that your design doesn't shoot the flames out past the edges of the pot. That'll just send all the heat up the sides.
Are you using a windscreen? Most alky stoves need them.
What fuel are you using? Make sure that it's denatured alcohol (like SLX or Kleen-Strip) or HEET in the yellow bottle. HEET in the red bottle doesn't work, nor does rubbing alcohol.
nsherry61
10-27-2015, 14:26
One important factor that you don't comment on is how high above the stove the pot is. Probably 1.5 - 2 inches will give you the best results depending on the stove.
Also, different stoves work differently, so knowing or seeing what stove you made can be important in diagnosing your problems. Pictures?
The pot is not the problem unless it is a very narrow pot on a side burner stove. I don't think REI makes any really narrow pots, so that is probably not your problem.
I have 32 holes 1/16 drilled, flames came around pot a little but no a lot.
Used windscreens, set it in cheese dip type can with two windows but in it, and aluminum foil circling whole thing, but still able to get air
denatured alcohol
One important factor that you don't comment on is how high above the stove the pot is. Probably 1.5 - 2 inches will give you the best results depending on the stove.
Also, different stoves work differently, so knowing or seeing what stove you made can be important in diagnosing your problems. Pictures?
The pot is not the problem unless it is a very narrow pot on a side burner stove. I don't think REI makes any really narrow pots, so that is probably not your problem.
I would say my pot was about a inch above, I will take pics and add them
Odd Man Out
10-27-2015, 15:05
Good advice above. Also make sure you have good air flow. You need adequate vents for air intake and outflow. Contrary to popular belief, the "wind screen" is not just to block the wind. They are also there to facilitate good air flow even when the wind is not blowing. For example, if you ever light charcoal briquettes for grilling, you can just pile the charcoal in a pile and light it. However, you can buy (or make) charcoal lighting devices that are really just a steel can with a grate on the bottom. Once the coals are lit, hot air rises up through the can, feeding oxygen to the coals and getting them going faster. Likewise your wind screen feeds oxygen to the stove and carries the heat up to the pot. Mine are cylinders of aluminum flashing. The nice regular shape promotes good air flow. The number of holes you punch in the bottom will control the air intake and the diameter of the cylinder controls the air outflow. Experiment as necessary.
Another thing you can consider is to put some insulating material underneath the stove. For this type of stove to work, the fuel in the reservoir needs to boil to feed fuel vapor out the jets. Thermal feedback from the burning fuel on top is needed to vaporize the fuel in the reservoir below. For the most part, the design of the stove should help get that thermal feedback balanced correctly. However, putting a stove on a cold surface and throw it off and dampen the stove's performance. Getting too much thermal feedback can make your stove burn out of control with a positive feedback loop. Putting your stove on an insulated pad can help minimize this variable and give more predictable and repeatable results.
Good advice above. Also make sure you have good air flow. You need adequate vents for air intake and outflow. Contrary to popular belief, the "wind screen" is not just to block the wind. They are also there to facilitate good air flow even when the wind is not blowing. For example, if you ever light charcoal briquettes for grilling, you can just pile the charcoal in a pile and light it. However, you can buy (or make) charcoal lighting devices that are really just a steel can with a grate on the bottom. Once the coals are lit, hot air rises up through the can, feeding oxygen to the coals and getting them going faster. Likewise your wind screen feeds oxygen to the stove and carries the heat up to the pot. Mine are cylinders of aluminum flashing. The nice regular shape promotes good air flow. The number of holes you punch in the bottom will control the air intake and the diameter of the cylinder controls the air outflow. Experiment as necessary.
Another thing you can consider is to put some insulating material underneath the stove. For this type of stove to work, the fuel in the reservoir needs to boil to feed fuel vapor out the jets. Thermal feedback from the burning fuel on top is needed to vaporize the fuel in the reservoir below. For the most part, the design of the stove should help get that thermal feedback balanced correctly. However, putting a stove on a cold surface and throw it off and dampen the stove's performance. Getting too much thermal feedback can make your stove burn out of control with a positive feedback loop. Putting your stove on an insulated pad can help minimize this variable and give more predictable and repeatable results.
Good stuff....I will go home and try some different things and take some pics as soon as I get a little free time, I will also time boil or slight boil if case may be
Odd Man Out
10-28-2015, 12:55
Good stuff....I will go home and try some different things and take some pics as soon as I get a little free time, I will also time boil or slight boil if case may be
You may also want to measure your fuel consumption. Know how much fuel you, how much time to boil, and also how much time until the stove burns out are all useful numbers to have. also, for comparisons, it helps to keep standard the volume and initial temperature of the water.
vamelungeon
10-28-2015, 19:55
I made some stoves out of aluminum cans. I finally bought this and am very happy with it, and have cooked many a meal with it. http://www.amazon.com/Trangia-327508-28-T-Mini/dp/B000LN7HUC/ref=sr_1_22?s=outdoor-recreation&ie=UTF8&qid=1446076369&sr=1-22&keywords=alcohol+stove
Odd Man Out
10-29-2015, 10:23
I made some stoves out of aluminum cans. I finally bought this and am very happy with it, and have cooked many a meal with it. http://www.amazon.com/Trangia-327508-28-T-Mini/dp/B000LN7HUC/ref=sr_1_22?s=outdoor-recreation&ie=UTF8&qid=1446076369&sr=1-22&keywords=alcohol+stove
That looks like a nice little system. I looks like it would be susceptible to wind. Do you use it with a supplemental wind screen?
donthaveoneyet
10-29-2015, 12:23
That looks like a nice little system. I looks like it would be susceptible to wind. Do you use it with a supplemental wind screen?
That's the Trangia Mini setup. I have one of those, have used it a fair amount. It's a nice little setup (the stove stand weighs about 1.8 oz IIRC). But yes, it is very susceptible to wind, you have to carry a separate windscreen.
vamelungeon
10-29-2015, 12:24
That looks like a nice little system. I looks like it would be susceptible to wind. Do you use it with a supplemental wind screen?
Yes, a piece of aluminum foil works nicely.
Instead of throwing a lot of luke warm advice at you just spend some time here: https://www.youtube.com/user/MrHiramCook
shakey_snake
10-30-2015, 05:20
First off, there's plenty of cheating youtubers trying to one-up each other. :P Don't be caught up in the rat race. :P
Secondly, given he time of year, I'd guess your water started out colder than in the video.
Third, alcohol stoves generally either burner hotter (aka faster), or more efficiently (aka slower). If you went with an "efficient" design and had cold water, 12 minutes for a simmer is probably about right.
Odd Man Out
10-30-2015, 11:15
First off, there's plenty of cheating youtubers trying to one-up each other. :P Don't be caught up in the rat race. :P
Secondly, given he time of year, I'd guess your water started out colder than in the video.
Third, alcohol stoves generally either burner hotter (aka faster), or more efficiently (aka slower). If you went with an "efficient" design and had cold water, 12 minutes for a simmer is probably about right.
I agree. Many videos are not very clear about their test conditions. After much testing, I can accurately predict how my system will perform in most conditions (air temp, water temp, water volume, fuel used). On the other hand, wind is not a variable I can test until I build a wind tunnel. Stay tuned.
Also, while generally true that efficient systems have low power and vice versa, it is possible to overcome this limitation. Based on my testing, I expect that I could bring 2 cups of 32 deg liquid water to a full boil in less than 6 min using 20 mL (2/3 oz) of 32 deg alcohol on a 32 deg day (no wind). But it took me a lot of stoves, wind screen, pot stands, pots, testing, and disasters to get to that point (only burned myself once - operator error with a Penny Stove).