iandol on fri 28 dec 01
Dear Vivek Patel <>
Although I have not seen your pictures I offer the following =
information.
Most Salt Glazes surfaces are crazed, so what you are experiencing is =
normal rather than unusual. Often the crazing is extremely fine in =
texture and is not noticed unless the glaze is thick and transparent.
I think if you can get into the industrial ceramic archives of the =
American Ceramics Society you will find that some producers in the past =
augmented their salt, that is Sodium Chloride, by incorporating a =
proportion of Boric acid or Borax into the mixture before baiting the =
kiln. The addition of a small proportion of Boron can help to change the =
Coefficient of Thermal Expansion of the surface coating which develops =
when common salt reacts with the clay body and is thought to reduce the =
incidence of crazing..
Do you know the mineral composition of your Black Fireclay or the =
origins of your Grog? Do you know the chemistry of your felspar? What =
cone are you salting at?
Best regards,
Ivor Lewis. Redhill, South Australia
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