Plasticfire

A smooth and highly plastic, buff burning, refractory, ball clay suitable as a minor addition to increase body plasticity. Plastic Fire is mined in Southern Saskatchewn and is both a ball clay and a fireclay. Is has a small amount of added buff stoneware clay to give us some adjustment on plasticity. Plasticfire differs from other ball clays in that it is ground to 42 mesh rather than 200 mesh. This coarser particle size makes this material unique and offers some advantages in many applications.

We have large reserves of this material and have found it to be quite consistent from mining to mining. Blends of Plastic Fire, Midstone, Kaosand and Palestone produce stoneware bodies of exceptional balance and consistency.

Process Properties

If you are using Plasticfire as an additive to other Plainsman native materials to produce a clay body, we suggest that drying shrinkage of the body be kept under 6.5-7% otherwise drying cracks are likely.

Plasticfire contains soluble salts that produce an attractive fired surface for some applications but are a problem for others (e.g. the salts are hostile to the deflocculation process, thus it cannot be used in casting slips). These salts can be precipitated using barium carbonate.

Firing

Plasticfire is more refractory than most other ball clays. Like others it can exhibit some soluble salts on the fired surfaces.

We do not grind this material to 200 mesh to remove all speckle. Thus Plastic Fire burns to an an iron speckled surface in reduction, the only ball clay on the market we know of that does this. If you are adding it to bodies in amounts higher than about 30% be careful, you may get excessive reduction speckling and high drying shrinkage.

Glazing

Plasticfire has a high free quartz content and thus it exhibits a high thermal expansion. Blends with high amounts of Plasticfire will likely shiver glazes. Conversely, bodies already exhibiting crazing problems with glazes will be improved by the addition of this material.

Physical Properties

 Drying Shrinkage (50:50 calcine:raw mix): 4.5-5.5%
 Dry Strength: n/a
 Drying Factor (50:50 calcine:raw mix): C110-
 Dry Density (50:50 calcine:raw mix): 1.80

Sieve Analysis (Tyler mesh):

   35-48: 0.1-0.4%
   48-65: 1.0-3.5
  65-100: 1.5-5.5
 100-150: 1.0-4.0
 150-200: 3.0-7.0
 200-325: 5.0-9.0

Fired Shrinkage (50:50 calcine:raw mix):

  Cone 6: 4.0-5.0%
  Cone 8: 4.5-5.5
 Cone 10: 5.5-6.5
 Cone 11: 5.5-6.5

Fired Absorption: (50:50 calcine:raw mix)

  Cone 6: 10.0-14.0%
  Cone 8: 8.0-10.0
 Cone 10: 6.5-8.5
 Cone 11: 6.0-8.0

Chemical Analysis

 BaO       0.2
 CaO       0.3
 K2O       0.9
 MgO       0.5
 Na2O      0.0
 TiO2      0.7
 Al2O3    19.3
 P2O5      0.0
 SiO2     66.0
 Fe2O3     1.8
 MnO       0.0
 LOI      10.3%

Plainsman Clays Ltd.
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX: 403-527-7508
Email: plainsman@telus.net

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