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glaze limit parameters. segar cone unity formulae

updated fri 9 mar 01

 

iandol on thu 8 mar 01


This topic seems to emerge periodically but I do not recall reference =
being made to information provided by Ryu Nagumo, author of Creative =
Ceramics. Japan Publications , Inc. ISBN 0-87040-251-X ,1974.
In "Composition of Glazes" pp 160-67 this author covers the process of =
glaze calculation. Provide are two related charts which correlate =
Temperature with Aluminium oxide/Silicon dioxide ratios and Temperature =
with Modifying Oxides up to 1 Mol so that they can be related to the =
Segar Unity representation of Molar Numerical Relationships.
An interesting feature is the provision for combinations and exclusions =
in selecting from the range of oxides.
However, no mention is made of the origin of this information. No =
footnotes or bibliography.
Pages 205-210 provides tables for the Elemental Oxide Unity Formulae of =
Segar Cones from cone 022 to 42 and their 'melting points'. All, except =
Cone 022 are lead free. I have reservations about saying that ' "Cones" =
have a "Melting Point" ' It is my understanding that they loose =
structural integrity and deform progressively under gravitational stress =
as heat works on their mineral components. They fuse completely when =
overheated, freezing to a glass structure when cooled.
I hope those with an interest in these topics are able to find this =
book.
Best regards,
Ivor Lewis, Redhill, South Australia.