The white one feels smoother, but it is actually far coarser. Why?

Monday 24th October 2011

Large particle kaolin (left) and small-particle ball clay (right) DFAC tests (for drying performance) demonstrate the dramatic difference in drying shrinkage and performance between these two extremes (these disks are dried with the center portion covered to set up a water content differential to add stresses that cause cracking). These materials both feel super-smooth, in fact, the white one feels smoother. But the ultimate particles tell the opposite story. The ball clay particles (grey clay) are far smaller (ten times or more). The particles of the kaolin (white) are flatter and lay down as such, that is why it feels smoother.

Pages that reference this post in the Digitalfire Reference Database:

Ball Clay, Kaolin, DFAC Drying Factor, Ultimate Particles, Primary Clay, Firing Shrinkage, Ball Clay

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