The Allens on wed 12 mar 97
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I've been using the following Chappel Cone 5 clear glaze with good results =
on a
stoneware called Sonoma. It holds colors true and has a nice gloss. I just
tried the glaze on a pot covered with black slip on the outside. Beautiful
outside but the inside of the pot was completely crazed (great if you are
looking for crackle). Can anyone tell what has happened and if it can be =
fixed?
Here's the formula
Neph. Syn. 46.2
gertsley borate 28.0
silica 20.0
kaolin 5.4
add
bentonite 1.0
cmc 1 tsp.
Any ideas would be appreciated.
Carla Allen
ridgerun=40scrtc.blue.net
Tony Hansen on thu 13 mar 97
> I've been using the following Chappel Cone 5 clear glaze with good results on
> stoneware called Sonoma.
> The inside of the pot was completely crazed...
>
> Neph. Syn. 46.2, gertsley borate 28.0, silica 20.0, kaolin 5.4,
> bentonite 1.0 cmc 1 tsp.
Sodium has the highest expansion of the oxides and with
46% Nepheline this glaze is loaded
with it. The gerstley is supplying sodium also.
That much nepheline also supplies so much alumina
that there is not much room left for kaolin to give the glaze
good working properties. I'd fix both problems at once.
--
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Tony Hansen, IMC - Get INSIGHT 5 beta or The Magic of Fire II at
http://digitalfire.com or http://www.ceramicsoftware.com
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