A highly grogged body that is almost porcelain-vitreous

Wednesday 28th November 2012

This is an unusual insight-live.com/glossary/125">cone 10R vitreous sculpture clay (code number L3118J). The grogless base burns dark brown and is almost porcelain-vitreous. All of the surface variegation is a product of the contrasting colour of the dark brown body and lighter coloured grog. Almost all of the fired porosity is from the refractory grog particles.

This was inspired by Craft Crank, a UK-made highly grogged body: A super-plastic base that can host a high percentage of coarse grog particles yet still offer very good workability (and be throwable, even non-abrasive, on the wheel). My base has 40% ball clay, 10% plastic kaolin, 20% Redart, 5% quartz and 25% 20x48 grog. Redart is an illite">illitic clay, containing K2O like a feldspar, the 20% here has enough fluxing power to vitrify the body. Given recent changes in Redart, this recipe could be modified to compensate (e.g. add iron oxide, use 45 ball clay instead of a 50 ball clay/kaolin mix, add 5% feldspar).

Pages that reference this post in the Digitalfire Reference Library:

Grog, Redart, A heavily grogged body: Yet throws surprisingly well, Grog, Sculpture

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