Glass Fusing ,Beadmaking & Lampworking Kilns: ARRANGED BY COMPANY: EVENHEAT, PARAGON, OLYMPIC, CRESS Most glass kilns Glass kilns heat from the top down as opposed to a ceramic kiln which heats from the sides. The reason for this is because most glass projects tend to be relatively flat, and we want the glass to heat evenly to prevent cracking and breaking. If you have a ceramic kiln with a programmable timer, you can get around this issue by making it heat up more slowly. Most glass-only kilns are not designed for ceramic projects.