For the clay, I normally use a fusible iron bearing clay which we dig locally. In
the 19th century, this clay was used to be used for making bricks and tiles. It probably matured at a very low temperature.
Any clay can be tried. I use ash from straw, pine and hardwood. I add quartz or
flint to the straw ash glaze (15-30%). The flint increases the silica content of the glaze
which increases opacity and opalescence (particularly with slow cooling), turning the glaze from yellow to
white or blue. No silica is added to the hardwood glaze but the ash content may
be increased to produce a more matte (crystalline) surface. This matteness is
enhanced by slow cooling.
We also use a shino glaze:
Glazes
and Slips
wood or straw ash 2 parts
felspar 2 parts
clay 1 part
I add a bit of the local clay to the shino to reduce the whiteness and enhance
the pink and orange colours which develop in the wood kiln, especially if it is cooled slowly.
Glaze samples
Samples of some glazes currently in use at Blackhills.
Click on thumbnail to enlarge image
