Alcohol stove idea

[Zack Freije]

Can I bounce this idea off of you folks?

I was thinking about the issue of a pot stand for many alcohol stoves and the weight this created.

I was thinking of a sheet of aluminum bent back and forth making a 1-2" thick accordion pattern. This would sit on top of the alcohol stove such as the BIOS from MBD.

Ideally, the flames would heat the aluminum directly and the pot would rest on top without any need for a stand. You could then use a Ti foil or other windscreen and a reflecting sheet of your choice.

The Jetboil canister has something similar to this attached to the bottom of their mug which they claim helps the boil time and efficiency.

Would this work?

[James Pitts]

I have never tried this. Give it a shot. It's a good idea. The heat exchanger on the JetBoil pot/mug seems to work very well, although all my "tests" have just been field experience and not very scientific.

Along these lines the JetBoil cookware has another feature I am thinking of trying to copy for use with my alcohol stove setup: The insulating sleeve on the outside of the pot. I am worried that the flames that spill over the edge of the pot will, however, melt the insulation. Obviously it's something I have not tried yet.

[Zack Freije]

How often do you need to adjust the windscreen on alcohol stoves? If there was a fixed windscreen, would that be a problem?

[James Pitts]

I use a piece of foil and I just wrap it loosely around the stove so the setup doesn't overheat. I see a lot of alcohol stoves that people run way too hot. They wrap the windscreen too tightly around the stove body and the stove overheats and burns the fuel too quickly.

[Kevin Egelhoff]

Zack,
I have also been thinking about this in great detail.
I have been trying to purchase aluminum fin material to build this but it is difficult to find the shape and sizes I think I need. I just ordered two different computer heat sink cooling fans that look like the prefect configuration for the bottom of the pot. Once I remove the fan and the brackets, they look like perfect little heat reflecting fins. No idea if the thin wall aluminum can stand up to the heat in a alcohol flame but I figured it was worth a shot. Anyone else thought about using these ?

[Zack Freije]

My Dad works for a major Aluminum mfg. company. I will talk to him today, but getting what we need shouldn't be hard.

I was working on a single, fully integrated product like the jetboil but I think that wouldn't be a good item for the market. I think it would have to be flexible and based on components. I think I would come up with a single fin ring that could be used or not. Then people can use their own windscreens and base reflectors, use whatever pot they like and any alcohol stove they want.

Then maybe it if it possible to come up with a good idea, I might make a fully integrated unit.

[Joshua Mitchell]

The idea has been tossed about on many a site, but there's a huge problems with non-integrated aluminum fins… they simply won't transfer heat effectively to the bottom of the pot. The Jetboil concept works because the heat exchanger is part of the pot, they are welded together…

No matter how close you get your tolerances, unless your fins are welded to the bottom of the pot, heat flux will be severely hampered by the film of air that will be between the two metals. It will be hampered so much that, frankly, you'll get the same performance as if the fins weren't there. Matter of fact some people who have tried (sgt rock for one if I remember correctly) have reported WORSE performance with the metal in the path of the flame.

[James Pitts]

Joshua, I think this is a very accurate statement. I have talked with a friend of mine who welds (he is really good) to see how to make a SUL version of the Jetboil pot. So far I don't have a solution but I did want to point out that I think you have made a very good point.

That said, the resulting heat transfer has GOT to be better than nothing at all. I would want to do some testing before I ruled out the potential for a significant benefit.

[Zack Freije]

Not sure about producing a Ti pot with aluminum fins welded to it.

Would people be willing to use an aluminum pot?

[James Pitts]

Most of my pots are aluminum except a few that are Ti. I would have used an aluminum pot with aluminum fins. I won't go into why I use aluminum pots because the last time I got into that discussion someone with a Dr. Frankenstein lab crushed my less scientific tests! Haha.

[Tony Beasley]

Hi James,

What this Frankenstein bit my Lab creates Balrogs and is located on Mt Doom Ha Ha.

My latest creation is under going tests and I hope I can post pictures this week.

Tony

[Jason Klass]

I don't think the problem is with heat transfer; it's with burning the aluminum. Even thicker aluminum flashing can burn up when in contact with direct flames from alcohol stoves. I think your idea is good, but you'll end up with a melted pile of aluminum at the end. Let me know if you experiment. I'd like to hear about the results.

[Joshua Mitchell]

"That said, the resulting heat transfer has GOT to be better than nothing at all."

Unfortunately, this isn't the case. What a lot of people forget is that conductors are insulators and insulators are conductors. Worse yet, the skin (there are more technical terms than this) of any material is a darn fine insulator. Simply setting two pieces of metal together DOUBLES the number of insulator (skin zones – and bad skin zones at that as they are material to air back to material). Without a fully welded connection, the temperature you would have to reach in order to drive an appreciable amount of heat across the connection would be enough as JK mentioned, you'd burn up the fins. Basically, you'd have to get the fins hot enough to make them radiators (think of how extremely hot the coils on your electric stove get… that's how hot they'd have to get).

I could get more detailed, but it get's into a lot of heat transfer terms that unless you've taken engineering thermo and engineering heat transfer are a little hard to grasp, and in some ways harded to explain.

BTW – If you can get a full weld (not just a spot weld as it only solves the issue over a small percentage of problem area), this might work, but without it… good luck… I would suspect any 'imrpovement' one sees is actually from side-effect phenomena (additional wind resistance, trapping the flame under the pot rather than it goine up the sides, etc.)

[Yukio Yamakawa]

現在、私のストーブ仲間の話題は、中央部に空気の煙突を作り作動させるテクニックの数々です。そのひとつとして加圧式もありますが、ここではカメラ用エアーブラシを使う、リアルターボ形式のアルコールストーブを紹介します。
作者は、coolysさんです。動画の終わり頃に、ターボによる激烈な火力が見れます。
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Now, my stove friend's subjects are many techniques which make and operate the chimney of air in the central part. Although there is also a pressurization type as the one, the alcoholic stove of the real turbo form using the air brush for cameras is introduced here. The author is Mr. coolys. The severe fire power by a turbo can see at the end time of an animation.

http://www.youtube.com/watch?v=JnOwveKNZgs

[Zack Freije]

I just noticed this new product. I will have to try to see it in person. It is to compete with the jetboil system.

They say it has a heat exchanger, is the most fuel efficient and boils water the fastest. However it appears to be 9oz heavier than the jetboil so that isn't good.

[Author]

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