search  current discussion  categories  glazes - faults 

lava/crater/textured glazes???

updated tue 28 nov 00

 

Martin Howard on sun 26 nov 00


to
add and also read somewhere that it only works in a reduction atmosphere.>

I recently posted about using raw 800 grade SiC. It produced craters all
right, and big ones.
The SiC itself produces the locally reduced atmosphere. The greater the
amount, the more widespread the effect.

Here in the UK, the usually sold grade is 200 grade. I wonder if that might
be the one you want with your cone and clay.

The deeper it lies within the clay, slip or glaze, the more cratering I
would expect it to cause, from my little experience of this material.

Martin Howard
Webb's Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
England
martin@webbscottage.co.uk

Marianne Bornet on sun 26 nov 00


I have been trying to obtain heavily textured glazes. I have done numerous
tests with recipes that I have found from various sources with very little
success. I have an electric kiln and fire between 1240 and 1260 because the
work is destined for out of doors and needs to be frostproof. I live in
France so won't bother with the clay info as none of you will have heard of
it anyway, other than to say that its a white grogged stoneware.

I have tried adding silicon carbide to the glaze recipes but have had more
success in adding it to a slip and then glazing. The problem is that I get
small gastly grey craters with this method once I have ground off all the
white frothy stuff. Though this colour is acceptable at times, I would
prefer to have a choice and would like to have larger craters sometimes -
assuming any appear at all !

I keep reading conflicting information as to the grade of silicon carbide to
add and also read somewhere that it only works in a reduction atmosphere.
I'm pretty sure that this is not so as Emmanuel Cooper has produced some very
interesting results in an oxidised atmosphere but I have discovered that his
book "Glazes" (which may or may not have suitable recipes) is out of print.

Does anyone have any relevant information or experiences that they would care
to share with me - even recipes I could test out ?

Thanks - in anticipation
Marianne