Chris Schafale on tue 10 oct 00
I'm working with the following glaze:
Frit 3134 50
Silica 20
EPK 15
Calcined EPK 13
Yes, I know it doesn't add to 100 -- that's because the 13%
calcined EPK is standing in for 15% raw EPK. I'm using the
calcined because the glaze tends to crack and peel as it dries,
otherwise.
Anyway, I'm noticing that this glaze, formulated this way, seems to
mature at a lower temp than the original. Cone 5 is fine, but at
cone 6 it starts to run and "separate" in an odd way. Any
suggestions on making it just a tad more refractory, without
changing its good qualities? It's very high in boron, which is part
of what makes it interesting, and perhaps is what makes it behave
this way.
Thanks for any suggestions.
Chris
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
June Perry on tue 10 oct 00
Without putting the whole thing on the glaze calculation program, a quick,
shot in the dark, try might be to add about 3% alumina hydrate and about 2%
more silica as a starting point. Saying, that, I think it's best to put the
formula on one of the calculation programs and raise the moles of the silica
and alumina enough to give you a 5-10% increase of those materials, while
keeping the proportions the same.
You can check out the archives for info on some of these programs -- one of
which is free for the testing.
Regards,
June
hal mc whinnie on tue 10 oct 00
add 2 to 5 % whiting
-----Original Message-----
From: Chris Schafale
To: CLAYART@LSV.CERAMICS.ORG
Date: Tuesday, October 10, 2000 1:20 PM
Subject: raising glaze maturity slightly
I'm working with the following glaze:
Frit 3134 50
Silica 20
EPK 15
Calcined EPK 13
Yes, I know it doesn't add to 100 -- that's because the 13%
calcined EPK is standing in for 15% raw EPK. I'm using the
calcined because the glaze tends to crack and peel as it dries,
otherwise.
Anyway, I'm noticing that this glaze, formulated this way, seems to
mature at a lower temp than the original. Cone 5 is fine, but at
cone 6 it starts to run and "separate" in an odd way. Any
suggestions on making it just a tad more refractory, without
changing its good qualities? It's very high in boron, which is part
of what makes it interesting, and perhaps is what makes it behave
this way.
Thanks for any suggestions.
Chris
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
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