M2 Red Clay
A pure clay that we dig straight out of the ground and grind into a powder. It matures in the kiln at higher temperatures than terra cotta but lower than stoneware. It is a high iron, moderate plasticity, smooth, dark burning stoneware.
M2 is our most important iron-bearing material. It works so well because of its consistency, the fact that it does not increase body plasticity, its broad firing range, fine particle size, lack of soluble salts, purity (low particulate iron impurities) and its linear (rather than volatile) maturing curve. We have a number of customers that use M2 pure (without any additions).
This is not as plastic as a typical pottery body, although it can be formed. In recipes it needs the help of ball clay and/or bentonite. A typical vitreous cone 6 recipe might be 80% M2 and 20% ball clay. Or 87% M2, 10% silica, 3% bentonite.
M2 fired bars (left) vs. M350. M2 fired at cone 6, 4, 2, 02, 04 (top to bottom). M350 from cone 8 down to 4 (top to bottom).
Used pure, M2 is over-fired by cone 6. This is ideal since adding ball clays (which are refractory) moves both the maturity and plasticity in the right direction. For the darkest colored bodies, M2 needs to be kept at a high percentage (so the lower ball clay will necesitate a little bentonite for plasticity).
Drying Shrinkage: 6.0-7.0% Drying Factor: C120
Sieve Analysis (Tyler mesh):
+48 (300 microns): 0.0-0.6% 48-65 (300-210 microns): 0.4-0.8 65-100 (210-149 microns): 2.5-3.5 100-150 (149-106 microns): 2.0-3.0 150-200 (106-75 microns): 5.5-7.5 200-325 (75-45 microns): 7.0-10.0
Cone 2: 4.0-5.0% Cone 4: 4.5-5.5 Cone 6: Overfired
Cone 2: 3.0-4.0% Cone 4: 1.0-2.0 Cone 6: Overfired
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 LOI 6.0%
M2 fired to cone 6 with Alberta Slip GA6-A base cone 6 glaze. This is over fired. Even though there is good red color, it is on the edge of beginning to bloat.
Safety Data SheetClick here for web view.
|Plainsman Clays Ltd.|
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508