Snail Scott on tue 19 nov 02
At 08:30 PM 11/19/02 -0500, you wrote:
>large bubbles the size of a quarter in the bottom of the mugs.
>Is this from overfiring the glaze?
Sounds more like underfiring, since the glaze tends
to stay cooler there (and thus more viscous) due to
the thermal mass of the shelf. (Often, glaze is also
thickest there because the thin, exposed rims which
are heated evenly from both sides get hot first, and
their glaze runs down to the bottom a bit.)
Many glazes go through a bubbly phase just below their
proper firing temperature, as the glaze melts and
traps gasses but is not yet runny enough for the
bubbles to easily pop.
-Snail
ranmcc on tue 19 nov 02
I recently fired my kiln and some mugs I had a the top right shelf of my
kiln and had large bubbles the size of a quarter in the bottom of the mugs.
Is this from overfiring the glaze? If due to overfiring can I refire to a
lower temp to smooth the glaze out?
Randy
South Carolina
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