I have been playing around with this for a while and decided to post some pics to see what you think. It works by the way. The idea is to assemble the three pieces and then insert the pot in it. It stays in place because of the aluminum bending towards the inside. It is easy to slide up and down to regulate the flame or increase the wind protection. It gets very hot and the heat is transferred to the pot (not the gas canister !)This afternoon I boiled 1.6 L in four different times and used about 25 g ( under 1 oz) of fuel. I store it wrapped around the sugar container with a rubber band ( to keep the shape).
Obviously it is custom made for my pot.
Franco

Edited by Franco on 03/01/2006 14:53:06 MST.

Franco, it looks like a clever design, but I have some doubts/questions, are you saying that:

1) the aluminum is in contact with the pot and that there is virtually no air space b/t the pot and wind screen?

2) it actually boils water faster than using a wind screen with a 6-12mm air space between the pot and the windscreen? I would have thought that it would boil slower with no air void between the pot and windscreen - especially in calmer conditions. What was the difference in fuel consumption with your windscreen and a more conventional one?

3) have you seen DrJ's design for using a pie plate with cut-outs for the pot supports and burner head as a bottom for your windscreen? This also protects the gas canister from overheating with possibly catastrophic results.

4) what was the diff. in boil times and fuel required to boil with and without a windscreen?

5) in actual use you still use a cover on your pot, right?

[Note: Boil is a useful way to compare approx. performance, lacking a thermometer. While talking boil here, some might remember that my older posts mention heating water to only ~180 deg F/~82deg C to save fuel, except if attempting to purifiy water, which, then, of course, a short boil is often required - depending upon the "bugs" one hopes to eliminate. 180F/82C is very hot. There is no way a person can even sip water this hot - at least I know that I can't - it burns/cooks some tissue of my tongue and hard palate. After heating water to approx. 180F/82C, place pot/bag in a cozy - generally only addes a few minutes to time in the cozy, but saves water heating time and fuel.]

Hi PJ
The shield is indeed in contact with the pot, apart from a few kinks in it and some of the curve that keeps it there. I have not done any tests comparing it with another wind shield, but it looks to me about the most efficient boil so far for me. I did see the pie plate solution, I will look into it again. As it is there is no chance of the canister over heating because of the gap between the screen and it.
Franco

Actually this is a very sounds (from a thermal transfer point of view) design.

The reason, you are likely getting the good results that you are getting is that your design 'traps' the heated air against the bottom of the pot (giving it enough time to transfer heat) while the narrow air gap (yes even with it 'in contact' there is an air gap) acts as an insulator. Whereas the 'pieplate' design allow the heat generated by the burner to escape up the sides of the pot...

It accomplishes this trapping because the sides of the 'windscreen' extend down below the burner causing the hot air to stagnate against the pot before cooling and falling. I would imagine that you would lose effeciency (defined as amount of fuel burned to amount of water boiles) if you had the burner turned up full bore, but as long as the burner is firing on 'low' you'd get pretty good effeciency.

Nicely done. I may do similar with my gigapower ti and try it out.

Edited by jdmitch on 02/22/2006 08:56:16 MST.

Hi Joshua
You are correct about the low heat setting, if I turn it up the gas will flare out, but with a slow burn ,8 to 10 minutes, the gas consumption is low.
I wil try with some holes to see if I can get a middle ground between speed and consumption.
Franco