Ivor and Olive Lewis on mon 15 may 06
I think most of us are aware that Silicon dioxide is not the only glass =
forming compound available for use when we make our glazes. Boric oxide =
and Phosphorus oxide also contribute to the formation of glass. As I =
understand things both of these glasses can contribute to colour =
creation.
Does anyone know if the normal rules of general chemistry apply to these =
multiple solvent systems? Do colouring oxides have a preference for one =
glass former or another? or do they have differing levels of solubility =
in different glasses.
For example, in the Floating blue recipe of Chappell (p186) the glass =
formers are Silica and Boron oxide from Colemanite. Colour comes from =
Iron and Cobalt oxides. Can anyone tell me how these colouring oxides =
are distributed within this glaze. Chappell describes this Cone 6 glaze =
as having "...a deep blue brown background of great depth..." =
(transparency ??) and lighter mottled blues which "...seems to float on =
the surface of the background glaze...."
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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