re: glazes popping off
- Glazes that pop off (usually on a rim or an area with relief) is a glaze fit problem called shivering. It is usually due to an incompatibility issue between the fit of the clay and glaze. If you are firing a white clay,it can also be too much talc in the clay body to fit the glaze. I have had it happen with underglazes on a white body. I never was able to fix it. I just learned what colors not to use with that clay. Sometimes I think it was just a wierd batch of clay or a change in the clay recipe causing it. Sometimes it was so bad on my white clay that I could literally tap the piece with a screw driver and the underglaze and glaze would pop right off the spot where I was tapping. I don't mean tapping hard, either. It's very frustrating when this happens, I know. Interestingly, the glazes and underglazes that have shivered on my clay in the past were all Amaco. The Duncans and Spectras did not do this. Leaf Green was a color that I learned to avoid, zs well as some turqoise color. You are right to wash the dust off before you glaze as this can also cause it. Perhaps someone in the group has another idea of how to fix the problem.