Annealing Thick Slabs
When a piece of hot kiln-glass is returned to room temperature, it cannot be allowed to cool too quickly. If cooled too quickly, the temperature differential throughout the glass can become too great, which may cause thermal shock or introduce stress into the glass.
This is why we cool kiln-glass slowly as it passes through the “annealing range”. If we cool kiln-glass at a slow enough rate, we can ensure the temperature differential throughout the glass is minimal.
This annealing chart has been formulated for use with Bullseye clear glass. It is based on a flat slab of uniform thickness that is set up in such a fashion that it can cool equally from top and bottom.
Revised December 8, 2020.