Janet H Walker on wed 9 dec 98
I've been slowly going through the stages of learning to slip cast. Now
I am at the stage of having finally fired a test piece in a glaze firing.
Needless to say, there is a new question.
The mold is a simple one-piece drain mold; the form is a cup. I glazed
the cup with two of my normal reliable glazes. The inside looks pretty
good. The outside is a mess, with little raised bumples all over but
especially in a sort of "asteroid belt" around the spot where the cup
curves most towards its foot. Say, what?
This is with a commercial slip, cone 6 Miller Dover white stoneware.
Raw glazed and single fired. (Is this the culprit? Do I have to bisque
if I slip cast?) The slip itself produced casts that were fairly brittle,
which the book I was using diagnosed as meaning "too little thixotrophy"
but the cure to that eludes me when you have a commercial slip.
Any slipmeisters out there who've dealt with the asteroid belt problem?
TIA,
Jan Walker
Cambridge MA USA
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