This is a 30 second model i made ti give you an idea of what I plan on doing.. and filling it with liquid nitrogen. Anyone can get liquid nitrogen as long as you have a vacuum botle to store it in (think thermos) and it cost's about 2$ a liter from pretty much any welding gas supplier (there are tons). It might cost me... $50 at most to make. I plan on scavenging the heat exchanger and the rest will be 1/6" steel.
I made one side clear in this so you can see the exchanger. It's really quite simple. Now that I thnk about it, I think I may put 2 exchangers with a gap in the middle. That way you can put ice/dryice and water in there.
