Tom Buck on tue 20 mar 07
Megamelon:
When I ask a local claybody formulator to give me a clue of what
is in it, I get a nice putoff. Years ago, after pressing, I was told a
particular claybody (no longer made) contained Jordan stoneware clay,
Goldart clay, and 10% nepheline syenite, and that the NS was causing the
bloating if I went to Cone 7+ instead of Cone 6.
You can expect to be told little about a claybody's composition.
if anything at all. and be aware too, that a Seger formula (UMF by some)
of a claybody will do little to assist you in finding out how it will
behave in forming and drying and firing. this is so because particle size
is more decisive than molar formula.
If you need to determine a claybody's CTE/COE, then use the 10
recipes for C10 porcelain glazes as a guide, and revise the recipes to
whatever lower cone you use (within a certain range). The 10 recipes
appeared in an article in Ceramics Monthly in January 1994, page 42.
good pots peace Tom B.
Tom Buck ) -- primary address.
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
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