Drat! Foiled again! (sorry, I just had to say that)

I've got some Ti foil, a BackpackingLight Ti windscreen. I'll have to dig it out and look at it. I haven't had it out for a while. The problem with Ti is the expense.

Al foil is cheap and readily available. Seems like the most viable option honestly. You can get various grades all the way up to "crafter's foil" which is the approximate gauge MSR, Primus, etc. use for windscreens for their stoves.

Steel is heavy and is not very flexible. Steel foil tends to be difficult to work with, and it's a great way to cut yourself. It's more like a shim than the flexiness of Al that we're all used to. I don't think steel is a very viable option. I've got a steel windscreen on my MSR Capillary Force Vaporizer stove. It's great as long as you just unroll it and use it as a windscreen, but no way could you make a water tight boiling vessel out of it.

Of course there's always Unobtanium, which is the perfect material for nearly everything.

HJ