M2

A pure, fine grained, medium plastic, high iron native clay that burns light to dark red from cone 06 to cone 6. M2 is mined in Grassrange, Montana from a thick seam of high quality material just under the surface. It is consistent and homogeneous and looks much like dark chocolate when the lump material is wet.

M2 is used as a source of iron in clay bodies at all temperature ranges. It is a plasticity-nuetral color addition (can be added to existing mixes without significant impact on plasticity).

Process Properties

M2 can be used as-is for many applications requiring deep natural fired color. It has about the right plasticity for plastic machine forming (slightly less than for hand modelling). Intermediate colors or fired maturity can be made by blending with our B buff-colored raw clay.

M2 contains soluble compounds that are hostile to the deflocculation process so it cannot easily be used in casting slips even if barium is added.

Firing

M2 burns to an attractive dark red at cone 3-4 but as it approaches the upper end of its firing range it turns dark brown. At cone 2 it fires to a warm red progressing down to a typical terra cotta color at cone 06-04.

Since M2 is a raw material it has no recipe that we can adjust to compensate for changes from mining to mining. Thus we do not exercise the same degree of control over its properties. Typically there will be slight variation in its plasticity, drying performance, fired color, and density.

M2 is a fairly clean clay, it normally contains minimal soluble salts that migrate to the surface and cause a white scum on fired ware. However, because of factors beyond our control, the amount of soluble salts does vary from run to run. Thus we cannot guarantee that fired products will be clean. Generally the problem is minimized by lower firing temperatures, lower water content in the plastic clay, faster drying times, and placement of the ware so that water leaves mainly on less critical surfaces.

Physical Properties

Drying Shrinkage: 5.0-6.0% Dry Strength: n/a Drying Factor: c120 Dry Density: 2.1

Sieve Analysis (Tyler mesh):

     +48: 0.5-2.0%
   48-65: 2.5-4.5
  65-100: 3.0-5.0
 100-150: 2.0-5.0
 150-200: 6.0-8.0
 200-325: 8.0-12.0

Fired Shrinkage:

 Cone 06: 2.0-3.0%
 Cone 02: 3.0-4.0
  Cone 2: 3.5-4.5
  Cone 4: 4.0-5.0

Fired Absorption:

 Cone 06: 10-13%
 Cone 04: 7.5-9.5
 Cone 02: 4.5-6.5
  Cone 2: 3.5-5.5
  Cone 4: 2.5-4.5

Chemical Analysis

 CaO       0.3
 K2O       2.7
 MgO       1.0
 Na2O      0.1
 TiO2      0.7
 Al2O3    13.5
 P2O5      0.3
 SiO2     69.4
 Fe2O3     6.1
 MnO       0.0
 LOI       6.0%

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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