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Cimtuff 9115 Talc


This could be a viable substitute for Natural Minerals C-98 Talc. The major question many have is about the iron content, will this fire as white as the C-98 product. Strangely, Cimbar does not include Fe2O3 percent on their data sheet. Their online resources make it difficult to tell where the talc is mined, but they do have a Texas facility so this could be from there.

If you are using this as a substitute for Texas talc in slip casting bodies it will likely be necessary to adjust the amount of deflocculant and water. You will likely have to read up on deflocculation and be willing to measure specific gravity and make test batches to fine tune a workable recipe. If ware does not have the plastic strength formerly, consider upping the percentage or ball clay (at the cost of non-talc ingredients) or using a more plastic (finer particled) ball clay.

Related Information

Cimbar Cimtuff 9115 Certificate of Analysis Report

This was received at Plainsman Clays is 2018.

4 Talcs in the same casting clay body at cone 04

The body is 50:50 talc and ball clay. These are Silverline (Montana), Natural Minerals (Texas) and Cimtalc (Indiana). The Texas talc is the whitest, the Montana is the darkest.

Cimtuff 9115 vs Natural Talc C-98 in a low fire white body

The clear glaze is G1916Q. Fired at cone 04. The body on the left is 50:50 Old Hickory M-23 ball clay and Cimtuff talc. The body on the right is a mix of KT1-4 ball clay and C-98 talc. It is firing whiter. But this is not only because of the talc, the KT1-4 ball clay is whiter-burning than the M23.


Oxide Analysis Formula
Materials Natural Talc C-98
Materials Talc
A source of MgO for ceramic glazes, a flux or thermal expansion additive in clay bodies, also used in the manufacture of cordierite.
Cimbar Cimtuff Talc data sheet
By Tony Hansen
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