3C Black Clay


3C is our whitest burning and most refractory fireclay/ball clay. It is grey in the dry form and very dark grey to black in the wet form. It is the main ingredient in our H441G sculpture body. We supply 3C in powdered form at 42 mesh.

3C stockpile at the Plainsman plant site.

Process Properties

3C is a very fine ball clay with some impurity particles (pyrite, mica, quartz, selenite, etc). In the plastic form 3C is very smooth. The raw lump material, when wet processed at 100 mesh, will produce and 80:20 minus:plus ratio (the oversize is mostly lignite particles). It is not as sticky and does not shrink as much in drying as typical commercial ball clays. In the slurry form it is almost black and suspends well. It contains some soluble salts that prevent it from being deflocculated. A powerful propeller mixer can break it down to ultimate sizes and the slurry can be easily wet sieved to remove larger particles.


The lignite that imparts the black raw color burns away during firing. The particulate impurities produce specking during firing, especially in reduction.

3C fired test bars. From upper and lower section of the seam. Cone 10R top and 10 down to 8 below that. The fired color and character is similar to a processed fireclay.

Physical Properties

 Drying Shrinkage: 7.0-8.0%
            Color: Grey (powder), dark grey to black (slurry)
      Fired Color: White
    Soluble salts: Light (similar to commercial ball clays)

Wet Sieve Analysis of Slaked Raw Lumps (Tyler mesh):

     +35: 0.3%
     +48: 0.5
   48-65: 0.8
  65-100: 1.7
 100-150: 2.9
 150-200: 3.0

Logo Plainsman Clays Ltd.
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508
Email: tim.lerner@plainsmanclays.com