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Plainsman Native Clay

Alternate Names: Plainsman FireRed

Oxide Weight612.00
Formula Weight662.34
If this formula is not unified correctly please contact us.
SADR - Sieve Analysis Dry +48 mesh: 0.5-1.0% 48-65: 2.0-4.0 65-100: 3.0-5.0 100-150: 4.0-6.0 150-200: 5.0-7.0 200-325:
GSPT - Frit Softening Point PCE 17
WABS - Water absorption Cone 4: 9.0-11.0% Cone 6: 7.5-9.5 Cone 8: 6.0-8.0 Cone 10: 5.0-7.0 Cone 10R: 2.0-3.0
FSHR - Firing Shrinkage Cone 4: 3.0-4.0% Cone 6: 3.5-4.5 Cone 8: 4.0-5.0 Cone 10: 4.5-5.5 Cone 10R: 3.0-4.0
DSHR - Drying Shrinkage 6.0-7.0

A natural, high iron, high temperature stoneware clay blend of a refractory low plastic red clay, a medium temperature medium plastic red clay and a bentonitic ball clay. Firered has medium plasticity and is thus a plasticity nuetral additive to clay bodies. It is slightly sandy and by itself is a deep, solid red at cone 10R with speckle. It is stable to cone 12+. This material is a better choice for impart red color to medium and high temperature bodies than typical low fire red clays (the latter tend to flux to brown rather than red colors even in bodies with low feldspar).

This material is a possible alternative to Newman red fireclay with caveats.
-This material is more plastic (thus ball clay or bentonite in the recipe can be reduced to compensate)
-FireRed is a little more vitreous (thus feldspar can be reduced).
-FireRed has a much coarser particle size distribution so homogeneous red burning bodies will look less so and they will have a much more toothy feel.
-FireRed has less staining power, you may need to augment it with iron oxide.

Fired Temperature, Cone 6 7 8 9 10 11 10R
Fired Shrinkage: 3.2% 3.4% 3.6% 3.6% 3.7% n/a n/a
Absorption: 8.2% 8.0% 7.8% 7.5% 7.1% n/a n/a
Fired Strength:
(lbs/ square inch) 3800 4200 4300 4300 4300

Sieve Analysis Wet Washed
(Root of 2 series) +35 +48 +65 +100 +150# +200 +325
0.1% 0.5% 2.5% 5.0% 6.0% 11.0% 11.0%

Texture: Sl. tooth
Plastic Index (1-10): 5
Green Strength (lbs/sqaure inch): 800
Dry shrinkage: 5.5
Dried density: 2.06
PCE: 16.5

Varying sizes of iron speckle in a high-iron reduction stoneware clay

Varying sizes of iron speckle in a high-iron reduction stoneware clay

Cone 10R firing of Plainsman FireRed (left), St. Rose Red 42 mesh (center) and St. Rose Red 10 mesh (right). The 10 mesh material produces a reduction speckle and deep red color that is very unique.

Varying sizes of iron speckle in a high-iron reduction stoneware clay

Plainsman FireRed (left) fired at cone 8,9,10,11 and 10R and Redstone (right) fired at cone 4,5,6,7,8.

FireRed fired to cone 10R with Ravenscrag Slip as an inner glaze.

FireRed fired to cone 10R with Ravenscrag Slip as an inner glaze.

This can fire almost black on reduction. However, as a pure material, it is prone to dunting as it is high in larger quartz particles.

Out Bound Links

In Bound Links

By Tony Hansen

XML for Import into INSIGHT

<?xml version="1.0" encoding="UTF-8"?> <material name="Firered" descrip="Plainsman Native Clay" searchkey="Plainsman FireRed" loi="0.00" casnumber="70694-09-6"> <oxides> <oxide symbol="BaO" name="Barium Oxide, Baria" status="" percent="0.300" tolerance=""/> <oxide symbol="CaO" name="Calcium Oxide, Calcia" status="" percent="0.500" tolerance=""/> <oxide symbol="MgO" name="Magnesium Oxide, Magnesia" status="" percent="0.600" tolerance=""/> <oxide symbol="K2O" name="Potassium Oxide" status="" percent="1.100" tolerance=""/> <oxide symbol="Na2O" name="Sodium Oxide, Soda" status="" percent="0.100" tolerance=""/> <oxide symbol="P2O5" name="Phosphorus Pentoxide" status="" percent="0.200" tolerance=""/> <oxide symbol="TiO2" name="Titanium Dioxide, Titania" status="" percent="0.900" tolerance=""/> <oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="15.400" tolerance=""/> <oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="66.300" tolerance=""/> <oxide symbol="Fe2O3" name="Iron Oxide, Ferric Oxide" status="" percent="6.900" tolerance=""/> <oxide symbol="MnO" name="Manganous Oxide" status="" percent="0.100" tolerance=""/> </oxides> <volatiles> <volatile symbol="LOI" name="Loss on Ignition" percent="7.600" tolerance=""/> </volatiles> </material>

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