Glass that breaks long after
Glass that breaks long after coming out of the kiln does so for one of two reasons:
– poor annealing
– incompatible glass
At just an hour out of the kiln the piece could still be cooling (especially if it was hot when it came out) and thermal shock is a possibility.
Often, the glass is actually cracked when it comes out of the kiln but we don’t notice it. Once cracked, even the “normal” stress that is in all glass may continue to increase the break until it becomes more visible.
Helios Kiln Glass Studio