In the last section on glaze flaws we discussed
- crazing
- crawling
- peeling or shivering
- pinholing
Many glaze defects can be countered by adjusting the balance of oxides
that end up in the glaze melt.
There are other faults that might look as though they are glaze defects
but that are in fact problems with the clay body. One of these is the
effect called bloating.
Blistering and cratering is an effect that results from the release
of gas from the glaze, a process that occurs with all glaze melts but
becomes a problem if the gas is still being released when the kiln is
shut down. Crater glazes are those developed specifically to take advantage
of textural effects that can result from glazes especially designed to
be releasing gas at the shut down.
Quality issues of excessive gloss, running or mattness are
usually the results of glazes in which the balance of flux to stabilizer
and glass former need adjustment in relation to the temperature that
the kiln is fired to.
In this lesson we will look at:
- bloating
- blistering and cratering
- dunting
- devitrification
- excessive gloss, dryness or mattness
- running