Test Bars Fired to Cone 7

Test Bars Fired to Cone 7

The one marked RC is my reclaim. It’s a mix of commercial and local materials. I have no idea of the percentage of each, as it all gets mixed together. Absorption at cone 7 is 1.4% with a 3-hour boil and then a 21 hr soak. Since this is a more rigorous test than most clay manufacturers use it is acceptable.

The unmarked bar is a body mix with my silty material. I tested a smaller batch of this for absorption and glaze fit. Hopefully this batch will be fine as well. Absorption at cone 7 was 0.07%. I’m worried this one may slump a bit. That’s a very low absorption. I did glaze a previous piece without slumping, so we’ll see.

The drying shrinkage on this was also very low, around 4% and the plasticity is kinda iffy. I’m not sure that I’ll be able to make anything large with it.

Silty Material Testing66.71
Mahavir Potash Feldspar23.91
Kyanite9.38

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