Making your own hexagonal shelves using calcined alumina

Tuesday 3rd September 2013

This homemade kiln shelf (left) for our test kiln was fired at cone 10. This is a third the weight (and thickness) of the cordierite one on the right. However it does not have the insight-live.com/glossary/89">thermal shock resistance of cordierite, uneven heatup can crack it. It is made from a body I slurry up consisting of 96.25% calcined alumina and 3.75% Veegum. It rolls out nicely and dries flat between pieces of plasterboard, taking about three days (if you try this and the body is not plastic then your alumina is not fine enough or you did not blender mix the slurry well enough). Alumina produces a lighter shelf than Zircopax and shrinks much less than refractory bodies we have tried (e.g. L4543), I cut the slab only 1/4" larger and it has fired to the same size.

Pages that reference this post in the Digitalfire Reference Library:

Calcined Alumina, A modern electric test kiln, a marvel of utility, Drying a flat slab of clay between sheets of Gyproc, My first zircopax kiln shelf

This post is one of thousands found in the Digitalfire Reference Database. Most are part of a timeline maintained by Tony Hansen. You can search that timeline on the home page of digitalfire.com.