Fear not, citizens! Just last night I tested what may be the ultimate pack-flat PSK water boiling container.

Turns out they make stainless steel foil pouches for protecting metal parts during heat treating. While only .002" thick, it is very tough material that blows away aluminum foil or baking pans. They are made from two pieces of foil seam welded along three sides.

I tried the smallest one available from McMaster-Carr: 2.5"x5". When puffed out it held just over 1/4 cup of water - a little too small. The next size up is 4"x6" which would be more practical.

The near-fatal downside is that the edges are razor sharp. The last thing you need in an emergency is to slice all your fingers open, especially because we have to assume you're down to just your PSK. I'll experiment with rolling the edges over to make it safe.

I used a pin to poke a hole in either corner near the open end and added a bail made from stainless snare wire. This is essential for hanging it over the fire. Within seconds of taking it out of the flames, you can hold it by the edges with your bare hands.

Another essential companion is a container for cooling and storage. Probably a plastic bag - if you had room for a rigid container you have room for a real cup too.

I'll take some photos over the weekend.
- Tom S.

"Never trust and engineer who doesn't carry a pocketknife."