Chic Lotz on sat 17 jul 10
Hi James,
I made a glaze from grass ash...... sort of....... it was cow dung
ash. About 10 years ago, I was reading that historically the wood
ash left in the fire box after a wood firing was often used to make
glazes for the next kiln load of work. We had just finished a pit
fire using cow dung. so I decided to see if dung ash could be recycled
and used in a glaze. They were local-grass fed cows so I researched
grass and found it was mostly silica.
Since glaze chemistry is all about the ratio of silica to alumina to
flux, I considered the dung ash as my silica component, added kaolin
for the alumina component, and used whiting as the flux. I dipped the
dung ash glaze alongside some shino on some pieces in a wood firing,
but the dung ash glaze was a bit too dry. So I added a tad of soda
ash for extra flux and bingo......... it is a very nice semi-matte
with an ashy look. Its a beautiful compliment to shino, and where the
dung ash glaze and the shino glaze overlap is a little bit drier and
even more of an ashy look. I suppose the overlap is drier because
shinos have so much alumina in them....... so the ratio of alumina in
the overlap section is much higher and drier. Not many glazes overlap
well with shino, so I was quite excited about it.
I would be glad to email a mug shot of the dung ash glaze to anyone
who who wants one: Chic@PotteryPoet.com
Enjoy,
Chic
www.PotteryPoet.com
Chic@PotteryPoet.com
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