The incredible plasticity that bentonite can impart to a throwing body


Wednesday 17th April 2019

The vase on the left is thrown from what I thought was a very plastic body, I got it very close to the same thickness from top to bottom (neither of these were trimmed). It has dried to 20 cm high and the thinnest part of the wall is 5mm thick. The one on the right was the same original size but has dried to 18cm high (so it shrinks much more). But the thinnest part of the wall is actually near the bottom, and it is only 2mm thick! How is it possible to throw that thin? The body is made from 50% ball clay and 50% bentonite. It took about 4 days to dewater the slurry on a plaster table. It is incredibly sticky and it shrinks 12% on drying (vs. 6%). It fires to a buff stoneware at cone 6.

Pages that reference this post in the Digitalfire Reference Database:

Bentonite, Plasticity


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