Alternate Names: New Foundry Hill Creme, Foundry Hill Cream, Foundary Hill Cream
Similar to a ball clay but having a lower drying shrinkage (about 6-6.5%). Although this is a fairly refractory clay, it has a high firing shrinkage, around 8% across the entire range from cone 7 to 11. Porosity drops slowly from cone 7 upward (7% down to 4% at cone 11 oxidation and 10 reduction). Used commonly in stoneware clay bodies.
The manufacturer states: An intermediate-grained engineered blend offering excellent moisture retention and plasticity properties. Ideally suited for a wide variety of stoneware applications and wet forming process.
Relative Viscosity (1.2 Sp. Gr.):* 1.28
Casting Rate: (gms per 15 min/426 cm2):* 209
Water of Plasticity:* 22.9
% Dry Shrinkage:* 3.94
Dry M.O.R., psi:* 239
Cone 04 8 11
Fired Shrinkage:* 0.2% 1.6% 1.9%
Absorption:* 20.2% 17.8% 15.2%
M.O.R. psi:* 758 2390 4630
Thermal Expansion, Cone 8: .493% at 700C
Oil Absorption: 28
Bulk Density, lbs per cubic foot: 37-45
Particle Size, Microns: 20 10 5 2 1 0.5 0.2
88% 73% 60% 44% 33% 21% 8%
*Specimens: De-aired, extruded, 50% ball clay, 50% flint
Jim Robinson observes that this material holds all the glazes in his GTS series without shivering, 'probably because cristobalite is not able to form'.
Top: Cone 10R (soluble salts are staining the surface). Downward: Cone 11-7 oxidation. These look very similar to a typical ball clay, perhaps not firing quite as white.
|Suppliers||H. C. Spinks Clay Company Inc.|
Clays that are not kaolins, ball clays or bentonites. For example, stoneware clays are mixtures of all of the above plus quartz, feldspar, mica and other minerals. There are also many clays that have high plasticity like bentonite but are much different mineralogically.
|Materials||Gleason Ball Clay|
|Pyrometric Cone Equivalent||31|