Aug 29, 2005 at 12:07 pm #1216707
Bill LawBPL Member
@williamlawLocale: SF Bay Area
Before I left on a recent 7 night trip with my new Coleman Exponent F1 Ultralight canister stove, I tried to construct a windscreen per the “instructions” here on BPL (see http://www.backpackinglight.com/cgi-bin/backpackinglight/00041.html).
It was a disaster (figuratively at least; nothing blew up).
I used aluminum flashing rather than foil. Theoretically, that should have helped.
As soon as I fired up the stove, the base heated to the extent that it began to sag, to the point where it basically collapsed.
I tried again, using small supports made from the same flashing to hold it up. This time I ran the stove a bit longer. The flashing burned to a crisp.
Has anybody actually replicated this kind of windscreen setup? Maybe it worked with the Gigapower stove because it puts out less BTUs, or, because it was only used in cold, windy conditions that mitigated the overheating.
My experiments leads me to believe that the heat that builds up between a windscreen base and the bottom of the pot is too hot to permit a windscreen constructed this way. But maybe I just did it wrong.
Bill LawAug 29, 2005 at 12:33 pm #1341065
I’ve made two canister windscreens, both out of oven liners following the model in the BPL article. Both were for my gigapower, but for two different sized cook pots.
I used one recently in the Wind Rivers for 7 nights with no problems.
The wind screen portion did get acquire a burn hole while on a trip in Death Valley where it came the closest to the flame.
Not sure about your stove, but the bottom/reflector portion on the gigapower hangs pretty far below the burner, so is unlikely to get too hot.
-adamAug 29, 2005 at 1:07 pm #1341069
The windscreen in the example is for the Giga Power stove. I use a Brunton Crux and that design would not work.
What I have done for my windscreen is take a piece of Aluminum Flashing and cut it so the height of the windscreen will fit in the depth of the pot. I also cut it to length so it leaves between ¼ and ½ inch gap between the outside of the pot and the windscreen when the folds on each end interlock. This way I know the screen will fit, rolled up within the pot it is intended to be used with.
Depending on the size of the pot, I use a hole-punch and punch out 3 or 4 holes one-quarter to one-third of an inch from the top, equidistant around the windscreen in its expanded form. If the pot has an external handle, I trim away space on the windscreen to accommodate the handle after I find the proper height.
To determine the proper height, I slide the windscreen down from the top of the pot until the bottom of the windscreen is just above the valve for the stove. I measure the distance between the top of the windscreen and the top of the pot; then I straighten large paperclips (the same number as holes and punched out in the windscreen) and bend a small hook to catch the top of the pot. Once you have the paperclips hooked onto the top of the pot, make sure the straight extensions are going through each of the holes in the windscreen (from the inside going out) and bend them up to support the windscreen at the proper height. This is like making custom ‘S’ hooks.
This way, the hanging windscreen surrounds the flame and the base of the pot; it does not enclose the canister, which could cause it to overheat and the concept works for any pot regardless of the size.
If there is enough space between the bottom of the windscreen and the burning head of the stove, you can also punch a series of holes ¼ to ½ inch from the bottom every inch. This way you can use the same windscreen for that pot when using an alcohol stove. All of my pots have their own windscreen using this concept.Aug 30, 2005 at 7:22 am #1341095
Inaki Diaz de EturaBPL Member
@inaki-1Locale: Iberia highlands
I’ve been using this kind of windscreen with the F1 with no problems. I build my windscreens out of pie pans, which are heavy duty aluminium foil and the screens work just as well for the F1 as they did for the MSR Superfly and the other stove I have. My only concern with the F1 was the heat could damage the plastic piece that’s under the pot supports but so far it seems it holds well. Never noticed a melting problem with the windscreen. Then, I always set the stove on low but not for avoiding melting the screen but for fuel eficiency. You might try that. I’ve never tried at full throttle, maybe the screen would melt then (but I’d say the plastic piece in the stove would melt much sooner).Aug 30, 2005 at 8:04 am #1341097
I made an improvised version of a windscreen for the F1. Oven pan aluminum foil works great. To make it easier to fit onto the F1, instead of cutting slits for the pot supports, I made actual folds in the foil for the supports to go into. This made for good fit and stability and probably provides better heat deflection.Aug 31, 2005 at 1:15 pm #1341158
Bill LawBPL Member
@williamlawLocale: SF Bay Area
Mike, Interesting that you mention this alternative strategy and using the same windscreen with your alcohol stove.
I had a windscreen that I’ve used with my Brasslite stove (made according the directions on Brasslite’s web page, as I recall). I came up with the same idea to try “hanging” that from the edge of the pot but decided it wasn’t worth the trouble: the lid didn’t fit so well afterward, getting the screen in place required too much futzing, etc. I also had concerns about the heat radiating to the canister with that setup (although I didn’t actually compare it to the heat without the screen). I think I might try this setup again, though.
I also only turned the stove up part-way, so I don’t think that was it. And the failure was almost immediate so it didn’t seem to allow too much room for lowering the heat.
Maybe the pot has something to do with it. I was using an Evernew 1.3L titanium pot. Maybe a narrower one reflects less heat downward onto the windscreen or something.
BTW, I didn’t find I had much need for the windscreen anyway, at least on this one trip so far. The couple times where there was any wind to speak of, I just positioned the stove behind some rocks and that seemed sufficient. Water still boiled quickly enough, with no noticeable loss of efficiency.
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