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DIY Alcohol Stoves -- Basic Design Principles

Posted: Wed Dec 14, 2011 11:37 pm
by hikin_jim
A buddy and I have been tinkering with DIY (Do It Yourself) alcohol stoves on and off for the last couple of years.

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I thought I'd put together a blog post on the design principles that I have learned as a result of all the tinkering and testing. What follows is NOT a "follow the steps and you'll get such and such a stove." Rather, I list some basic design considerations for making decent DIY alcohol stoves. For pragmatic reasons, the post is limited in scope to open type burners made from aluminum beverage cans.

For those of you who would like to try your hand at making such stoves, there is a Standards for DIY Alcohol Stoves section in the appendix that you can benchmark your DIY stoves against.

So, without further ado, I give you: DIY Alcohol Stoves -- Basic Design Considerations

HJ

Re: DIY Alcohol Stoves -- Basic Design Principles

Posted: Thu Dec 15, 2011 10:11 pm
by rlown
is alcohol just aimed at UL? Not sure what i'm asking as I burn white gas in a Coleman. So, lets say I'm cooking pasta for 4 at 10k'. That's a LOT of water, and then a food load added to that for probably 8 mins. Is that even possible and how does that compare to white gas? guess I'm looking for a guide in what is best to use when, fuel-wise..

Russ

PS: your standards prompted this post..

Re: DIY Alcohol Stoves -- Basic Design Principles

Posted: Fri Dec 16, 2011 12:24 am
by hikin_jim
Hi, Russ,

Alcohol is slow. It just doesn't have the heat content that WG does. Now, for one person or a party of two, it's not so bad. But for four? The more water you're talking about, the more the slowness is multiplied. I know people who use alcohol stoves for bigger groups, but it wouldn't be my first choice.

OK, so the downside of alcohol is that it's slow. What's the upside?
  • Well, first, weight. You can make a stove out of a Coke can. A stove can weigh as little as 7g. The knob on a white gas stove probably weighs 7g.
  • Second, alcohol stoves are cheap. Buy two Cokes, cut up and re-assemble the cans, punch some holes with a push pin, and you've got a stove. A decent white gas stove starts around $70. I can put an entire alcohol stove system together, a decent one, for less than $10
  • Third, peace and quiet. There's little or no noise. Alcohol burners are really really quiet.
  • Fourth, convenience. If you pick an alcohol stove that conforms to my standards, there's no pumping or priming; just pour in the fuel, light, and go. I love the fact that there's little fuss or hassle. Just set everything up, light it up, and come back in about 7 minutes. I go set up camp or whatever.
  • Fifth, bulk. With a WG stove, you've got a fuel bottle, a burner with legs and pot supports, and a fuel hose. All that stuff takes up room in your pack. With an alcohol system, you still have to have a fuel bottle (but it can be just a little plastic bottled water type bottle), but your entire stove is the size of a very short coke can. Pop it in your shirt pocket, and off you go.
Just a few thoughts,

HJ

Re: DIY Alcohol Stoves -- Basic Design Principles

Posted: Mon Dec 19, 2011 11:30 am
by Flux
The rule of thumb from a test I have seen in relation to alcohol vs canister is that over a long trip the canister begins to be more efficient in the weight comparison. This is due to the extra weight of the canister and/or any unused portion of gas you carried in and out. You need more fuel to boil the same amount of water but the alcohol stove realized great savings in that you only carry exactly what you need and a very light stove.

From what I generally understand is that an alcohol stove would be difficult to use to boil pasta. Typically you pop a bit of fuel in it and boil up 2 cups of water for meals or soup or tea or whatever. Typically that is fine unless you are doing some other cooking. I'm not saying it would not work, but I think a canister or WG stove would be better suited.

I built a Penny can stove one day on a whim. It was kind of fun and really easy to do. it worked like charm the first time. I guess there are certain design features for each type that are important. You want it to heat up and boil it's fuel, but not too hot. Type, hole size, number of holes, rim, etc all play in. Luckily I had the benefit of someone else doing all the testing and I just followed their design. Simply, they are fun to make and use and you get that awesome DIY satisfaction. I'll take mine along on my next overnighter where I know I am just boiling or simmering and give it a go. I did have a few small issues here and there with getting it to light correctly, but that's just some trial and error.

it's tough to beat a weekend trip with one 8oz canister doing all the work for 2 people with a 3 oz stove and a Ti pot.

Re: DIY Alcohol Stoves -- Basic Design Principles

Posted: Tue Dec 27, 2011 6:37 pm
by hikin_jim
This is a subject that gets debated endlessly. I've seen some write ups where the alcohol stove comes out ahead even on longer trips, BUT I think overall the general consensus is that gas works out lighter on longer trips. Canister gas packs a lot more heat per gram than alcohol. Yes, an alcohol stove can be very light, but on a longer trip (5 person-days is the number I usually hear), the weight of the low-heat-density alcohol becomes greater than the weight savings of a lighter stove.

However, you have to be careful. If you have to carry a second canister, remember you'll have to carry the weight of the empty first canister throughout the rest of the trip. The empty weight of a steel canister is considerably more than the empty weight of a little plastic alcohol fuel bottle. If you have a trip that can't be done on a single canister, it may be worth taking a second look at alcohol.

Of course if you have a party of three or more, then gas pretty much makes sense irrespective of which system is lighter. I personally just don't want to wait for the length of time it takes to boil water for three people on an alcohol stove.

HJ