Firing and Glaze Advice Needed
Just unloaded a kiln full of pots.
Lots of pinholing.
Believe it's a clay body problem.
Pots fired from reconstituted porcelain (same formula) in soda kiln to cone 10 next to pots fired with this particular batch of porcelain are not pinholed.
Porcelain contains:
grollegg
tile 6
custer spar
silica
pyrotrol
bentonite
Glazes boiled/pinholed, particularly glazes that have a wider firing range, and those that flux earlier or like a lower temperature. The clay body is "lumpy", some bits are whiter than others, and some parts have shrunk away from the lumpy bits. Pots made from the newer batch that have pinholing in the glaze (amber celadon and a barium matte turquoise) are next to pots thrown from a reconstituted batch containing no scraps from this current questionable newer batch, and the reconstituted batch pots have not pinholed. Looking at older pots made last year from a completely different batch, no pinholing problems with the amber celadon in them, furthermore, even when amber celadon was thinner on those older pieces, no pinholing problems.
The question is: can I refire any of these pieces with the pinholes and have the glaze settle down? If so, how may I refire them? What would work best? electric, refire in soda?, gas no soda? no reduction? (the soda deposits seem to exacerbate the problem in areas where the glazes used are more "fluxy"). Would refiring them in soda with adding more soda make them worse?
Thanks!!! for any advice!
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