Expert: Sam Kelly - 5/8/2009

Question
I have been a potter for 16 years and decided to try using a clay found on my land.  I normally fire to cone 6 glazed in an electric kiln with commercial clays and glazes.

I dug 50 lbs of this clay (bright amber in color, wet), cleaned it up by slaking and drying, and fired a piece for shrinkage measurement and quality.

The clay shrank a little when drying, but didn't shrink at all when fired to a cone 04 bisque.  I broke a thin square that had been bisqued and fired half to cone 6.  The piece fired to cone 04 and the piece fired to cone 6 fit together perfectly with no shrinkage.

Going to be doing more experimenting with it, for one, including some in a cone 12 wood firing next week, but do you have any idea what kind of ceramic material I am dealing with, and to what use I could put it?

After cone 6, was a light tan, extremely absorbent, and very low density.

Answer
Hi brian, it should be absorbent and low density at coe 06, no higher, this is the glaze application temp/cone.

You are going to have to add some talc.

You are going to have to do test's for porisity, absorbition of water.

on allexperts they will only allow 3 folllow up questions, do a search on Google for 'Clayart', join.

Sam