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SGT Rock
2005-04-08, 22:10
I've been using the test Pentagon stove that is made from aluminum for a few days now. I've put it through some big fires - much bigger than you would need to boil two cups of water. After all this it isn't showing any signs of warping or fatigue.

It's 22 gage aluminum sheet you can get at Lowe's for about $4. I'm just wondering if I am making a big mistake if I recommend this material for the DIY builder. It certainly is a lot cheaper and easier to work with than the same amount of Ti.

http://hikinghq.net/ionstove/images/100_0343.jpg

http://hikinghq.net/ionstove/images/100_0345.jpg

I've also found that fanning the fire is a lot easier than using a blow tube.

Anyway, are there any experts than can tell me how much heat this sort of stuff can take?

dixicritter
2005-04-08, 22:58
Well when it fails then the heat was too much?? Just guessin. ;)

CanoeBlue
2005-04-08, 23:14
Sarge,

1.) You can melt aluminum with a charcoal fire and a blower - but then you can forge iron that way too. The secret is in concentrating the heat.

The aluminum that you are using is fairly heavy and the design has a lot of surface area and will have a tendency to dissipate the heat enough that my guess is that the aluminum will work OK.

2.) Dixie has a good point. You need to know where "fail" is - or for that matter, whether you can reach it. Load one up, fire it up - see if you can melt it. If you can't - you have your answer.

3.) stick a short (12 - 16 inch) length of surgical tubing on to the end of that blow tube so you don't have to get right down with the stove and the smoke. I expect that you will like it better.

SGT Rock
2005-04-08, 23:44
Dixie and I sat out there for about an hour making bigger and hotter fires to see how it would hold up. I tried normal sorts of things to induce failure, nothing like using a torch or anything like that.

The fan method is just so easy to do from a lounge chair. :D

dixicritter
2005-04-08, 23:45
He's such a pyro... lol.

Turk
2005-04-09, 17:20
Rock,

If you know some basic info about the type of aluminum you bought this site is fabulous for referencing every property of any metal you could possibly want to know about. Try it out.

http://www.matweb.com/reference/aluminum.asp

Being a welder I use this site to reference heat treatments all the time. I am no metalurgical expert or anything, but if there is a specific question you have about your aluminum in regards to heating it, I can help you make the appropriate calculations or at least point you to the formula to figure it out.

Turk
2005-04-09, 17:36
The problem with testing the aluminum ... or any metal for that matter in this application is the lack of any kind of constant to apply to a mathematical formula. Your stove in "wood fired" mode poses the greatest margin of error in trying to determine a point of maximum acceptable metal fatigue.

The biggest problem is that the easiest formulas are based in BTU's. Its great on paper, but falls sort when you introduce real world variables.

For example "a campfire that is 20" in diameter, burning softwood under conditions of zero wind, and producing flames of 15-20" tall emits a BTU range of anywhere from 65-85,000 BTU's per hour." - this is a completely stupid statement i found google searching.

Think about that statement. Not only does it offer up a completely huge and useless BTU range for you to work with mathematically. But it ignores countless real world variables that would further affect the calculations.

What kind of wood is in the fire?
how many pieces?
Is there a well established bed of coals beneath the burning wood?
Wind? what about wind? everyone knows wind can turn a little fire into a blow-torching inferno.

I think the answer for you Rock is to find a formula for metal fatigue that doesnt work in BTU's. I just dont think it can result in an accurate answer. You're probablly going to get more answers through field test methods.

SGT Rock
2005-04-13, 21:34
The stove body of the Atomic Fireball is loosing integrity. The heat is just too much for it I guess. The new titanium stand is holding up great though. Even though the stove is now getting hot enough to begin to melt itself, the pot doesn't seem to boil faster than about 4 minutes. So what I now am faced with is what we have been talking about so far in another thread - effective heat transfer to the water from the stove via the pot.