Adrian & Jackie Brien on wed 18 oct 06
From: Adrian & Jackie Brien
Date: Tue Oct 17, 2006 9:24:55 pm America/Vancouver
To: CLAYART@LSV.CERAMICS.ORG
Subject: WHITE SLIP GLAZE CONE 5/6 CRACKING
I have the following slip glaze which is cracking in crescent shapes
about 1/4 inch long or less.
It is: Ball clay 75
Kaolin 10
Flint 10
Feldspar 5
I love the slip- it's white and takes irons well. I use it over a
Seattle Pottery Supply clay CKK6- with grog. I put a clear gloss over
top. I'm not sure if the slip is designed to be fired to a higher
temperature or not.
The cracking is irregular,and unpleasant .
John Britt on sun 22 oct 06
Adrienne and Jackie,
This is a cone ten slip. Notice that the clay is 85% the filler is 10 %
(silica) and the flux is 5%. You are probably getting cracking because of
shrinkage from the high clay content. You can either apply it thinner or
apply it thin and bisque (drive off the water) and then apply a thin coat
again or deflocculate it.
But either way I would try to find a cone 6 slip if you are firing with a
cone 6 claybody.
Best,
John Britt
www.johnbrittpottery.com
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