DIY Alcohol Stoves -- Basic Design Considerations

[hikin_jim]

I doubt I'm going to put any of the pros out of business with this, but I thought I'd try to distill out some of the basic considerations of DIY alcohol stove design and put things in one place in relatively concise form.

So, after much discussion, much tinkering, and much testing, I give you: DIY Alcohol Stove Design -- Basic Considerations



HJ

[moytoy]

Nice work H_J....My penny stove is like my dog (if I had one) It is friendly only to me and I am familiar only with it. I will not forsake my trusty penny stove. I've been using one for 10 years.

[Maddog]

Good information...very well done! Thanks! MD

[oops56]

hikin_jim in your blog you say cook stove cook what ham and bacon no most only boil water tranga is the only one that can cook

[lunatic]

Very interesting post. Thanks again for the info. Never thought about the 1:1 ratio of opening to height before, nor about this:

Yes, width matters, but the width of the opening is more important than the width of the entire burner.

[hikin_jim]

hikin_jim in your blog you say cook stove cook what ham and bacon no most only boil water tranga is the only one that can cook

Hi, RJ,

Yes, I'm being a little "forgiving" with my use of the word "cook," aren't I? For these purposes, if I can get a hot meal out of the deal, I'm going to call that cooking.

You are right though, cooking "real" food requires the ability to simmer which a simple stove like the one I'm featuring just plain isn't going to do. Now, can you rig up a simmer ring for a simple stove? Sure, and I know people who have done it, but that's an issue for another, future post.

HJ

[hikin_jim]

Good information...very well done! Thanks! MD

You're welcome. Hopefully it's really practical stuff. This is all based on field testing (hopefully the photos got that idea across). Not much theory here.

I deliberately chose aluminum drink cans. I wanted something fairly "accessible" to the average person: materials that are inexpensive, readily available, and relatively easy to work with, materials that don't require a lot of specialized tools or a great deal of skill. In other words I wanted something that even a klutz like me could work with.

HJ

[hikin_jim]

I added a little something at the bottom of my blog post: An appendix with some "standards" for DIY stoves that any stove can be benchmarked against. These are just my thoughts; feedback welcomed.

HJ

[blackbird04217]

It was nicely written and the most useful portion, to me, was the appendix that you added with benchmarks. I never measured the weight of my stove, or amount of fuel I've used. It seemed to boil in under 5 minutes or so in nearly all situations on my thru.

That said, it is interesting you found that width of opening vs height matter most in design. Any plans/thoughts to test multiple ratios to dial the efficiency in a bit?

[hikin_jim]

It was nicely written and the most useful portion, to me, was the appendix that you added with benchmarks. I never measured the weight of my stove, or amount of fuel I've used. It seemed to boil in under 5 minutes or so in nearly all situations on my thru.

Thanks. Those are just my thoughts, so I'm open to other ideas. It does seem like 0.5fl oz/15ml alcohol to boil 2 cups/500ml of water is what a really efficient stove can do.

I wish that I had had a list to benchmark myself when I started playing with alcohol stoves in 2007! I had no idea what constituted a decent stove. Hopefully it's helpful to some.

That said, it is interesting you found that width of opening vs height matter most in design. Any plans/thoughts to test multiple ratios to dial the efficiency in a bit?

I've actually done quite a bit of playing around, and I've discussed this with others who are pretty knowledgeable about alcohol stoves. Everything seems to point to a ratio of about 1:1 as being a practical ratio. You can make the stove more efficient by changing the ratio, but then the stove takes forever to get any water to boil. My gut feeling is that if a stove takes longer than about 10 minutes to boil 2 cups of water, then we're getting past the practical stage of things.

For example:
Say I can boil 2 cups with 15ml of alcohol in 8 min. Pretty practical.
Now say I change the ratio and I can boil 2 cups with 14ml in 13 min. Yeah, it's more efficient, but is it worth it to take an extra 5 min just to save one mlof fuel? To me, that's going beyond practical and getting into gram "splitting".

Yes, you can get greater efficiency beyond a 1:1 ratio (either a taller stove or a narrower opening), but is it worth it? I guess each person has to answer that for himself.

HJ

[blackbird04217]

It should be noted that my 5 minute timer is based on gut feeling that it really doesn't take long to boil 2 cups of water. Also it was the first ever stove I built/used - it may not be very efficient though as I also stated I didn't measure my fuel used. So; take what I say with that in mind, I could be just rambling wrong numbers, though it does get me wondering, almost enough to test.

[hikin_jim]

It should be noted that my 5 minute timer is based on gut feeling that it really doesn't take long to boil 2 cups of water. Also it was the first ever stove I built/used - it may not be very efficient though as I also stated I didn't measure my fuel used. So; take what I say with that in mind, I could be just rambling wrong numbers, though it does get me wondering, almost enough to test.

I actually never really bench marked my stoves until I started hiking with this one guy -- who had a better stove than I did. On this one hike, I ran out of fuel while he still had plenty. I got disgusted with my stove and started trying to figure out a) what were some good numbers on efficiency and b) what kind of stove would get me there. Hopefully, my post answers both of those questions.

HJ

[mkmangold]

Good info; nicely done. Thanks for this.

[hikin_jim]

Good info; nicely done. Thanks for this.

You're welcome. Hope it's useful -- and hope you come up with some good stoves.

HJ