Why did this piece came out of a decal firing crazed?

Wednesday 11th March 2015

This Cone 10 matte mug has been refired to attach decals. During the refire the Quartz-containing body passed up through quartz and cristobalite inversions while the glaze did not (all of its quartz was converted to silicates during the previous glaze firing). The sudden expansion in these two zones stretched the glaze and cracked it. Had that glaze been better fitted (under some compression) it would have been able to survive.

Pages that reference this post in the Digitalfire Reference Library:

GR10-J - Ravenscrag Cone 10R Dolomite Matte, Crazing, Quartz Inversion, Decal, Glaze Crazing

This post is one of thousands found in the Digitalfire Reference Database. Most are part of a timeline maintained by Tony Hansen. You can search that timeline on the home page of digitalfire.com.