Watch out for iron particles in ball clays

Monday 14th April 2014

These are the oversize particles (from the 70, 100, 140 and 200 mesh sieves) from 100 grams of a commercial ball clay. They have been fired to cone 10 reduction. As you can see, this material is a potential cause of specking, especially in porcelain bodies. It is not only wise to check for oversize particles in clays, but firing these particles will tell you if they contain iron. A 200 mesh screen would be a good start for this test, it would catch all of these.

Pages that reference this post in the Digitalfire Reference Database:

SIEV Sieve Analysis 35-325 Wet, Ball Clay, Specking

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