This is when you should program a firing yourself

Tuesday 20th January 2015

This is Polar Ice cone 6 insight-live.com/glossary/71">porcelain that has been over fired. The electric kiln was set to do its standard cone 6 fast fire schedule, but a cone in the kiln demonstrates that it fired much higher (perhaps to cone 7 judging by the bend on the cone). This is a translucent frit-fluxed porcelain that demands accurate firing, the over fire has produced tiny bubbles and surface dimples in the glaze. The mug rim has also warped to oval shape. The lesson: If you are firing ware that is sensitive to schedule or temperature, use large cones and adjust if needed. If it fires too hot like this, then program to fire to cone 5 with a longer soak, or cone 5.5 (if possible). Or, program all the steps yourself; that is definitely our preference.

Pages that reference this post in the Digitalfire Reference Library:

Soaking, Glaze Blisters, Over Firing of Ceramic Glazes and Bodies

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.