Sio-2 PRNI Black Stoneware with Impalpable Grog. Sold in 27.5lb bags 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 very exclusive of PRN range and becomes an ideal artistic mean of expression. In reducing atmosphere, metallic effects with shades of blue are obtained. Suitable for tableware (food-safe), according to ISO 6486:1999. Available in extruded body (moist form). Recommendations for use with glazes Use zinc-free (Zn-free) glazes to prevent from unexpected reactions such as bubbling or color changes. Other elements that can react are zirconium (Zr) and tin (Sn). We recommend consulting your usual glaze supplier to ensure proper suitability with this ceramic clay body. Do not use glazes with a low coefficient of thermal expansion (a25-300ºC 60x10-7ºC-1). Firing - Ceramic kiln high fire Weight/Volume - 27.5 lbs - 12.5 kg Grog - Impalpable grog State - Moist form (plastic body) Stiffness - For wheel throwing and handbuilding Firing range: Cone 5-6 (2192-22264ºF / 1200-1240ºC) Bisque firing temperature: Cone 06 (1832ºF / 1000ºC) Water content: 21% Plasticity (IP Atterberg): 22 Carbonate content (CaCO3): 0% Drying shrinkage: 7.0% Firing shrinkage (1240ºC): 7.1% Porosity (water absorption at 1240ºC): 1.3% Dry bending strength: 4.6 N/mm2 Fired bending strength (1240ºC): 33.3 N/mm2 Thermal coefficient (a25-500ºC): 51.1x10^-7ºC^-1
