Boiling glass? It doesn’t really “boil” but if you take it up to a rather high temperature, say 1700-1800 degrees you can get it to “boil”. Add bubble powder or baking soda to the bottom layer of glass and heat it up very hot and the bubbles will work their way up bringing whatever colors that are in the lower layers up to the top. My new glass friend, Jamie Burress mentioned it and I had to check it out some more. Watch the video from glass fusing made easy…and then check out Bullseye’s tech notes about how glass reacts to heat. And check Jamie’s work cause it’s super cool!