Monthly Tech-Tip | No tracking! No ads! |
An art tile company is bisque firing a heavily grogged red stoneware body to cone 5 and then finishing with a range of low temperature boron glazes. But these glaze bubble and blister defects are happening! There appears to be some sort of LOI gas-monster particles present. They could be in the grog. And, the body contains two dark burning fireclays, both could contain also rogue particles. To identify them a sieve could be used to pull out the larger ones (e.g. 35 or 42 mesh) and these could be spread in a thin layer onto a porcelain tile and fired to cone 5. Taking closeup photos before and after should spot the guilty ones, they will have a visibly different form (e.g. melting, puffing up, altered color). These pandora particles seem to be activated at cone 5 and capable of continuing to gas even at low refire.
Glossary |
Glaze Bubbles
Suspended micro-bubbles in ceramic glazes affect their transparency and depth. Sometimes they add to to aesthetics. Often not. What causes them and what to do to remove them. |
---|
Buy me a coffee and we can talk