Potclays Original Craft Crank

Pics from autumn 2019 firing – cone 12 reached. Gold colour on right is ash deposit. Note that a dinner plate of this clay, fired on its side, softened and bent.

Manufacturer: Potclays Ref 153-1114

One of our flagship clays, the original Craft Crank is often copied but never bettered. Carefully graded grog additions to a superb blend of clays makes this clay outstanding for all larger forms of slabbing and handbuilding. The unique plasticity of the clay enables the more adventurous potter to throw with it.

Regarded by many as the best crank clay available, Craft Crank™ is unsurpassed as a handbuilding clay. The unique blend of fireclays and ball clays produce a pleasant toasted colour in oxidation whilst the speckled orange-brown under reduction is unrivalled.

The trademark Craft Crank toasted colour occurs when the soluble salts in the body combine with the iron content at higher temperatures. This toasting is more pronounced in thicker section ware which has been dried slowly and fired to a higher temperature.

Recommended Firing Range 1170-1300C
Applications: Tiles / hand building / slab building / general and large domestic. (Can be thrown but must be thick walled, and takes the skin off your fingers!)
Texture: 8 (1 smoothest, 10 most coarse)

Composition:

SiO2	TiO2	Al2O3	Fe2O3	CaO	MgO	K2O	Na2O	LOI
61.3	0.9	26.3	2.8	0.4	0.3	1.4	0.6	5.8

30% fireclay, 27% other clay.
42% #20 grog.
Shrinkage 9%@1100 and 1200
Thermal expansion 0.31%
Vitrification 1280 – 1320C
Firing 1170 - 1300