Ball clay powders were minus 200 mesh. Right? Wrong!

Wednesday 9th April 2014

These are the oversize particles (from the 79, 100, 140 and 200 mesh sieves) from 100 grams of a commercial Gleason ball clay. They have been fired to cone 8 oxidation. There is 1.5 grams total, this is within the limits stated on their data sheet even though the material is sold as 200 mesh grade. Firing the samples shows whether the particles contain iron that will produce specking in porcelains and whiteware. In this case there are a few. We do this test on many materials and this is typical of what we see.

Pages that reference this post in the Digitalfire Reference Database:

SIEV Sieve Analysis 35-325 Wet, Particle Size Distribution

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