Product Details Nigra 2002 Black Stoneware Body with Black Grog At 1050°C and above, it develops into a dark anthracite colour. Application Temperature: 1000°C – 1240°C (Cone 6) Specifications: Grog / Graining: 20% / 0-0.2mm Drying Shrinkage: 6.8% Firing Shrinkage: 1140°C: 4.7% 1190°C: 7.0% 1240°C: 8.2% Water Absorption: 1140°C: 7.3% 1190°C: 3.0% 1240°C: 0.2% Sintering (Water Absorption ≤2%): 1210°C Thermal Expansion Coefficient (20-400°C): 68 × 10⁻⁷/K (Pre-firing: 1200°C) Safety Concerns with Black Clays Concerns about the safety of black clays, both in the studio and on functional ware, are valid. Historically, some black clays were colored with manganese oxide, a known toxin NIGRA 2002 sold under the Primo-Pro label is manufactured by a reputable European supplier and widely sold throughout Europe. We have our supplier’s absolute assurance that this body (pigmented with manufactured stains) is safe to use. Description Primo Pro Nigra2002 Black Stoneware Clay is manufactured by a reputable European supplier and widely sold throughout Europe. We have the manufacturers absolute assurance that this body (pigmented with manufactured stains) is safe to use and does not contain Manganese Oxide. Primo Pro Nigra2002 Black Stoneware Clay is a stoneware body. It is suitable for plastic forming methods. Chamotte proportion: 20 %. chamotte size range: 0 – 0.2 mm ( black chamotte ) Firing Colour: black Recommended Firing Temperature Range: 1000-1240ºC Technical Data (typical values) UNFIRED Moisture: 20.0% plastic Loss of Ignition: 5.0% Wet to Dry Shrinkage: 6.8% plastic properties FIRED Specimen Firing Temperature [ºC] 1200 Dry to Fired Shrinkage [%] 7.0 Water Absorption [%] 2.5
