Onyx Black Porcelain (5kg) 1200-1240C

About

164-ONYX - Onyx Black Porcelain | Recommended firing range 1200-1240C / Cone 6-7*

Onyx Black Porcelain takes on a beautiful black/graphite colour when fired as recommended to the upper part of its firing range. Onyx is coloured with ceramic stain. The fired colour may turn brown above the recommended firing range. Perfect for wheel-throwing and modelling, and performs well in conjunction with Aneto White Porcelain, Upsala Blue Porcelain and Lagoon Turquoise Porcelain for techniques such as inlay and nerikomi. Suitable for tableware. Supplied in a 5kg pack. Onyx Black Porcelain is suitable for tableware (food-safe), according to ISO 6486. The manufacturer recommends zinc-free clear glaze such as Mayco SW004 for Onyx Black Porcelain.

Indicative texture 1 (Smooth 1-Coarse 10).

SIO2 Technical Data:

• Biscuit: Cone 06 (1020ºc)
• Water content: 20%
• Plasticity (IP Atterberg): 11
• Carbonate content (CaCO3): 0%
• Drying shrinkage: 5.4%
• Firing shrinkage at Cone 6: 10.3%
• Porosity (water absorption) at Cone 6: 0.0%
• Dry bending strength: 3.1 N/mm2
• Fired bending strength at Cone 6: 39.8 N/mm2
• Thermal coefficient (at 25-500ºC): 54.3x10-7ºC-1"

(*) Firing range recommended for the clay to develop its best performance, both in terms of technical and safety characteristics, under conventional firing conditions. The colour samples may show temperatures outside the recommended range to provide a broader view, but these are pieces fired under controlled conditions.

To comply with RHA regulations concerning tail-lift deliveries (where there is no fork-lift truck available at the delivery point) the maximum net weight of clay we are now permitted to pack on standard pallet is 950kg (76 x 12.5kg bags of clay). To achieve the best price for your clay, please add the full 1000kg to your cart when checking out and we will make the necessary weight adjustment/refund when we receive the order.

We have added cone numbers to our firing ranges for guidance purposes. Please refer to the 60c/hr column for large regular or self-supporting cones on the Orton Cones Conversion Chart which can be downloaded here.

Technical data is approximate and provided for guidance only. Our Clay Analyses sheet can be downloaded here.

Collections

• Coloured Clays
• Specialist Clays
• View All Plastic Clays
• Clay - Black

Ask a Technical Question ISO 6486 standard on food safety in ceramic ware SIO2 Clays A4 2024