Acrylic is the only way to fly, man. But, theoretically speaking, most bubs are made from thin, cheap glass. If you've got a PYREX, however, it may be freezable without risk.

My friend made this one for me, and she said they're like 35 bucks. I wouldn't pay for it, but it does work quite well. And the stem was only so big, that ice must have done a great fucking job of cutting the harshness down to nothing. I wish there was a way to smoke cool misty vapor like a J. Vaporizers aern't traditional smoking, so this felt like it had absolutely no pain, and I took monster fucking rips.