SIO-2 Berlin Gray Stoneware High Fire Pottery Clay, 27.6 lb (12.5 kg) | Kiln-Fired Clay for Wheel-Throwing, Handbuilding & Modelling - Ready-to-Use

"Grey stoneware clay with 40% impalpable grog 0-0.2 mm (up to 80 Mesh). Formulated for artistic ceramics, it is ideal for throwing and modelling smooth pieces with fine details. The high content of grog confers an excellent behaviour during drying and firing. Depending on the firing temperature, it develops an interesting range of greys, from cement to dark grey, which satisfies the most avant-garde trends in artistic ceramics. Suitable for tableware (food-safe), according to ISO 6486. Available in extruded body (moist form). Firing range: 2269-2381°F / Cone 6-10 Biscuit temperature: 1855°F / Cone 06 Water content: 17% Plasticity (IP Atterberg): 16 Carbonate content (CaCO3): 0% Drying shrinkage: 5.4% Firing shrinkage at Cone 10: 4.6% Porosity at Cone 10: 4.1% Dry bending strength: 2.4 N/mm2 Fired bending strength at Cone 10: 26.2 N/mm2 Thermal coefficient (?25-500°C): 53.8x10-7°C-1 Storage: Protect ceramic clay bodies from direct sunlight, avoiding excessive temperature changes and protect from frost. Use: Technical details are available with information on the characteristics of each product and its use. It is recommended to test clay body prior to large scale use in order to verify suitability in both the ceramic process (shaping, drying, firing and decoration) and the final application that is expected to be obtained. Safety: All SIO-2 clay bodies are certified by the Art & Creative Materials Institute (ACMI) and conform to ASTM D-4236 safety guidelines. From the manufacturer of SIO-2: CERAMICA COLLET S.A. Always in your hands Founded in 1874, our company manufactures ceramic clay bodies for industry, pottery and artistic ceramics, and natural clay for crafts, fine arts and education. Our target is to innovate, developing products made with natural clay which, in many applications, satisfy the high requirements of our customers. Our Quality System, certified according to ISO 9001:2008, is the setting for continuous improvement. Social responsibility, respect, and care for the Environment are two fundamental points in the philosophy of our firm. Ceramic body manufacturing process Clay mining from nature Clays are natural materials that are extracted from mines and open-pit deposits. The selection and origin of each type of clay depends on its desired physical characteristics (colour, plasticity, melting point, etc.). Receiving, mixing and grinding The clays arrive at the factory in a dump truck and are unloaded into the feed hoppers, where they are mixed and crushed through a continuous process. The result is a clay composition in a crumbled state that combines the specific clay formula to make a ceramic body. Clay storage The clay composition is controlled and stored in the external storage bays. With the storage, the homogenization of the components is obtained and the natural maturation and drying of the clay is favoured. Grinding The ceramic body manufacturing process begins with the dry grinding of the clay composition using pendular mills. The result is a clay composition in powder that flows through pipes (pneumatic transport) to the storage silos. Dosing, kneading and extrusion The clay composition is dry mixed with other solid components (grog, minerals, pigments) and is dosed with the liquid phase (water and additives) in an automatic process controlled by sophisticated dosing and weighing systems. The resulting formula is mixed in the kneader, obtaining a body in a plastic state, which is extruded in the form of a compact bar (under vacuum) with an automatically controlled consistency (hardness). Packaging and palletizing The extruded bar is cut into individual blocks (units) of defined and automatically controlled weight. The units travel through a carousel where they are automatically packed, labelled and palletized."