Black Stoneware Clay
PRNI is a black stoneware clay body with 40% impalpable grog (up to 80 Mesh). Formulated for artistic ceramics, it is ideal for wheel-throwing and modeling smooth pieces with fine details.
The high content of grog confers an excellent behavior during drying and firing. Its beautiful and intense black firing color in oxidizing atmosphere is unique to the PRN range and becomes an ideal artistic mean of expression. In reducing atmosphere, metallic effects with shades of blue are obtained.
PRNI is suitable for tableware (food-safe), according to ISO 6486:1999. It is available in extruded body (moist form), in a 27.6 lb. package.
Firing range: Cone 5-6 (2205º-2269ºF)
Biscuit: Cone 06 (1855ºF)
Water content: 21%
Plasticity (IP Atterberg): 22
Carbonate content (CaCO3): 0%
Drying shrinkage: 7.0%
Firing shrinkage at Cone 6: 7.1%
Porosity (water absorption) at Cone 6: 1.3%
Dry bending strength: 4.6 N/mm2
Fired bending strength at Cone 6: 33.3 N/mm2
Thermal coefficient (a25-500ºC): 51.1x10-7ºC-1