Chris Stanley on sun 22 sep 02
Don's White Liner Glaze?
Whiting 20%
Custer 40%
E.P.K. 10%
Flint 30%
100%
Add: Zircopax 10%
This one is sweet with over glazes!
Dave Finkelnburg on mon 23 sep 02
Chris,
Don's White Liner Glaze, according to Insight, is also relatively low in
expansion, at least for the stoneware bodies I am familiar with. the
calculated expansion is virtually identical to that for the Snowden's White
recipe you posted earlier today.
The 10% Zircopax lowers the calculated expansion dramatically. I have
always wondered if, with such a refractory material as zirconium silicate,
the glaze expansion really does change that much. Perhaps someone more
knowledgeable could comment.
The Don's White glaze is, of course, Leach's Cone 8 Limestone glaze
from his, "A Potter's Book," with Zircopax added.
Regards,
Dave Finkelnburg
----- Original Message -----
From: "Chris Stanley"
> Don's White Liner Glaze?
> Whiting 20%
> Custer 40%
> E.P.K. 10%
> Flint 30%
> 100%
> Add: Zircopax 10%
>
> This one is sweet with over glazes!
Ron Roy on thu 26 sep 02
Hi Dave,
This is a little tricky - zirconium silicates do lower expansion but I
don't think as much as calculation indicates.
Zir/sil crystals do not enter fusion in glazes at our temperature - not
much anyway. They remain crystals and thereby give opacity.
The question becomes - how much does a crystal - surrounded by glass -
affect the over all expansion of the glaze.
We do know that expansion of crystals is unpredictable by calculation - so
how to get a true reading of zir/sil crystals and how to compare that with
calculated expansions of silica and zirconium as calculated in a glaze as
if they were separate?
I have not done the experiments but I would like to know the answer -
anyone got enough curiosity to do some web searching? Surely this has been
researched somewhere.
RR
> Don's White Liner Glaze, according to Insight, is also relatively low in
>expansion, at least for the stoneware bodies I am familiar with. the
>calculated expansion is virtually identical to that for the Snowden's White
>recipe you posted earlier today.
> The 10% Zircopax lowers the calculated expansion dramatically. I have
>always wondered if, with such a refractory material as zirconium silicate,
>the glaze expansion really does change that much. Perhaps someone more
>knowledgeable could comment.
> The Don's White glaze is, of course, Leach's Cone 8 Limestone glaze
>from his, "A Potter's Book," with Zircopax added.
> Regards,
> Dave Finkelnburg
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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