I guess I can post something instead of lurking all the time.
SIGUY said it before about tin foil and making a cup to hold water. I have never had any luck with that at all. Everytime I opened up the tin foil it leaked, and held just a little bit of water.
I can still boil all my water all at once in it.
What I do is I make the tin foil cup and fill it with as much water as it will hold. Then I fill it with water about two inches worth and I have never been able to have the small cup hold more than that before leaking.
I have a home made FOODSAVER bag that I cut and made to fit in my PSK tin. Mine are 4'' wide and 9'' long. I made one side that has the neck about another 4'' longer and an inch wide. Basically the bag looks like a and "L" with the vertical part the filler neck and the horizontal part as the main part of the bag. I made them like this so I can fold the neck closed and then use a twist tie on them so they don't leak.
Anyway, I fill the bag with water and put it in the tin foil cup with just a little water in it. It will boil the water in my bag without melting it. Kind of like a double boiler. Depending on how much water the cup holds, I may add just a little so it doesn't go dry.
I form the tin foil to support the FOODSAVER bag and to protect it from burning or melting. I can still use the tin foil for cooking if I really want to, but to be honest, I never have. The tin foil always holds enough water to do this, but never enough, at least for me, to boil enough water to make it worth while. I have had to use a couple sticks to help support the foil cup or lean it against a chunk of wood.
The bags are made to be boiled, so there is no chance of it melting while in the boiling water. I don't put it right on the fire, but right next to it.
I hope I explained that well enough. Maybe I should go back to lurking.
