I had a lovely bowl with one small glaze flaw/small blister crater inside. I dremeled it slightly and put a bit of clear glaze over the spot and re-fired it, again at cone 6. Now it has blisters all over, inside and out! Ruined. Why?
Laguna B-Mix cone 6 clay. Coyote's Ice Blue glaze. One difference in the firing—fast speed the first time (although I forgot to take the prop out until late, so the lid was slightly open during the first 1700 degrees F) and medium speed the second time. Surely that couldn't have caused the new blisters, could it?