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Monday, August 1, 2011

Windscreens

In my recent article in Seattle Backpackers Magazine (Aug 2, 2011 edition), I mentioned what my preference is in terms of a windscreen for an upright canister stove (well, at least for trips where weight isn't super critical).  Something like the below (keep reading if this looks too heavy; more ideas follow):

This is a self standing windscreen made by Olicamp.

I discuss my preferred windscreen set up in my article, and I'll go into some more detail later on in this blog post, but for now I'd like to discuss some of the alternatives that are out there.  Before you look at these alternative windscreens, you should carefully read my article and all of the safety warnings in the article.  Using a windscreen with a canister stove can be very dangerous.  Make sure that you monitor the temperature of the canister frequently with your hand.  If the canister feels hot, it is hot:  Take immediate steps to cool the canister.  DO NOT EVER LET THE GAS CANISTER OF YOUR STOVE GET HOT*.

That said, let's look at some of the options out there for windscreens for an upright canister stove:

One particularly ingenious light weight idea is Jim Wood's Kite Screen.
Photo courtesy of Jim Wood
The kite screen has an excellent reputation and is definitely a workable solution to the wind challenge. For me personally, the kite screen is a bit more set up than I like to mess with, but many people really like it. By the way, if you haven't checked out Jim's site, it's worth a look.  Lot's of valuable information.  Recommended.

Another option is construct your radiation shield such that it has a lip around the edge, like so:

 You can then use that lip to put a windscreen in place like so:
Advantages:
  • The canister is fully vented making it very unlikely that you'll overheat the canister.
  • Since the windscreen doesn't need to reach all the way to the ground, a shorter windscreen can be used.
Disadvantages:
  • It's a little hard to secure the windscreen on top of the radiation shield.  Wind tends to knock the windscreen around.  However, I've seen lots of examples of clever clips and other means to secure the windscreen in place.  This is definitely something worth experimenting with.
  • The lip on the radiation shield tends to get bent up when in my pack.  A completely flat radiation shield is easier to pack.
  • Because there is such a tight mating of the windscreen and radiation shield, it's going to get really hot inside the windscreen.  Plastic or other sensitive parts like piezoelectric ignition systems could get damaged.
  • Because the radiation shield needs to securely support the windscreen, you'll need to use a little bit heavier material for the radiation shield than you otherwise would.
  • Since the valve control is inside the windscreen, you have to lift or open the windscreen to adjust the flame.  If you're just boiling water, who cares?  Just turn the stove on and let the danged thing boil.  But if you're simmering, you may need to adjust the flame.  A huge deal?  No.  Inconvenient?  Yes.

Another option is to take a titanium bowl and cut slots and holes in the bottom of the bowl such that the burner and pot supports protrude through the bottom of the bowl.
Photo courtesy of Denis Hazelwood
With a pot in place:
Photo courtesy of Denis Hazelwood


I think the bowl idea has a lot of merit.  Of course you have to sacrifice a titanium bowl, and it takes a bit of skill to make cuts that don't look really amateurish. The bowl in the photo was made by Denis Hazelwood.

Finally, there's always my preference:
This self standing windscreen consists of a series of stiff aluminum plates with wire rods that act as hinges.  This type of windscreen has several advantages:
1.  It's self standing.
2.  It's heavy enough that the slightest breeze doesn't knock it over
3.  It's tall enough that it can handle larger canisters and larger stoves.  The canister in the photo is a 220g Snow Peak canister, and the stove is an MSR Superfly, a relatively tall stove.
4.  It's very fast to set up (seconds)
5.  The rods that act as hinges can be pushed into the ground to help secure the windscreen.

BUT this type has a significant disadvantage:  it's heavy, weighing in at 201g (7 ounces) which is about the weight of a 110g sized fuel canister (when full)!

For a lighter windscreen that works along the same lines, simply replace the above windscreen with a windscreen made from multiple sheets of household aluminum foil, folded at the edges such that the windscreen stays together, like this:
The above windscreen is significantly lighter, but far more subject to being knocked around or blown over by wind.  You'll probably need to brace the windscreen with rocks and such.  The above windscreen is also significantly less durable.  But it does work.


So there's a very brief survey of some of common windscreen set ups that I've seen for upright canister stoves
1.  Self Standing
2.  The Kite Screen
3.  Windscreen mounted on radiation shield
4.  Windscreen made out of a bowl or similar item

For any of the common windscreen set ups, your imagination is the only limit to the types of materials that you might use.  Items such as pie tins, 36 ga. aluminum tooling fool, baking pans, catering dish lids, titanium bowls, household aluminum foil, roof flashing, etc. are all fair game.  Just remember:  DO NOT EVER LET THE GAS CANISTER OF YOUR STOVE GET HOT*.


With that in mind, get out there and use your stove for what it is intended for:  Good eats!!


HJ

*Letting the canister get some heat in cold weather isn't a bad idea; it will improve performance. You still need to monitor the canister's temperature even in cold weather. Even when it's cold out, that canister must never be allowed to get so hot that you can't comfortably touch it with your bare hand.  I'm talking about "normal" hands here.  Be careful if your hands are really cold.  Really cold hands may not give you enough sensation to tell how hot that canister really is.  Let your hand rest on the canister a while.  If the canister is really hot, you'll know it soon enough!  My point is that a quick touch with cold hands may not be enough.  Check the canister.

5 comments:

  1. I use a homemade pot cozy which really cuts down on the fuel consumption anyway so I think I'll manage without the wind screen. I have actually had my pocket rocket go out when the wind was blocked by the stove being too close too a log or other natural wind screen. I do like the article that shows how to float a canister to gauge the amount of fuel left.

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  2. That's really odd that a PR would go out because it was close to a wind screen. Was it a really gusty wind?

    HJ

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  3. I use a bit of carbon felt for a skirt, wrapping it around the pot so that it hangs just like a half inch below the burner. That cuts off wind from above but is still above the valve, above the canister, and not impeding the input air supply. The felt (a.k.a. welder's cloth) is UL and secures with either a metal Ace bandage gripper or a silicone band (i betcha a rubber band would work too). That same carbon felt is already on and when we're done heating it functions as pot grabber and good-enough-cozy, too.

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    Replies
    1. wondering if you could share/elaborate? I've been looking at heat-proof materials and many have fiberglass, which I don't really want to deal with (especially near food)

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  4. That titatnium pot with holes at bottom is genius solution. Good job. About overheating - I did windscreen from beer cans, and attach plate directly to cardrighe with gas. Simple, and efficient, but might be use only in winter.
    During summer time, cannister becomes overheated.

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My apologies to real people, but due to Spammers I have to moderate comments. I'll get to this as rapidly as possible but do understand that I like to hike and there's no internet in the wilderness. Take care and stove on!