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more on s-cracks

updated thu 13 feb 03

 

Paul on wed 12 feb 03


There is evidence that suggests s cracks are more likely with hard clay than
with softer clay. I know a potter from western PA who was routinely throwing
6 tons of clay per month. He would sometimes come to my friends studio where
i used to work for a week at a time and throw about 2,500 pots during that
time. Anyway, he said he was having a lot of problems with scracks using
Standard Ceramics 153 stoneware body and then due to wrist problems he
started special ordering the clay to be made softer than normal. After that,
he said they stopped altogether. I think he estimated a year's throwing at
70,000 pots, at least at his main job, and said no s cracks at all.
I talked to an engineer about this at standard ceramics and she said it is
likely due to the fact that you can get better compression with soft clay. I
throw straight from the pugmill without turning the pugs sideways and get
very few cracks, except with pieces that are hard to compress the bottoms.
For those, i will probably start turning the pug sideways since so many
people seem to get good results that way.
Paul B