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cone 6 red glaze - layering and safe

updated sat 21 apr 07


Ivor and Olive Lewis on fri 20 apr 07

Dear Tom Sawyer,

You ask << I am doing a considerable amount of "glaze layering". As most =
of us know such a process effects the eutectic temperature of melt. How =
does this affect food safety. ?>>

I don't think eutectic reactions will have any effect during the melting =
phase but interaction due to diffusion might lower or raise the =
solidification temperature of the zone between the interacting layers of =
glaze. Glass Transition temperature could be an important factor. If you =
are using glazes from MC6G then you will have some idea of the =
temperatures at which that occurs. I would anticipate that if both =
glazes contain Boron the temperature at which solidification happened =
would be lower rather than higher. This might encourage more flow across =
the surface of your pots.

Glaze solubility might be affected if there was an increase in alkali =
metal (Sodium, Potassium or Lithium) content at the outer surface of the =
combined glazes. Remember that Sodium and Potassium Silicates are water =
soluble but Calcium (Wollastonite) and Magnesium (Enstatite) silicates =
are not.

Best regards,

Ivor Lewis.
South Australia.