ASHPOTS@aol.com on sun 7 apr 96
Hello All: I am hoping to build a soda kiln and I was wondering if I need to
put extra silica sand in my clay to attract the soda. I used to do it when I
did a lot of salt. I love to have a juicy salt build-up. Also, has anyone
tried my CONE 6 ASH GLAZES that I posted.
Capt. Mark Issenberg
MADE IN THE SHADE PLANTS & POTTERY
7780 SW 118th Street
Miami, FL 33156 USA
(305) 232-0278
(305) 232-0278 FAX
Gail Nichols on mon 8 apr 96
>----------------------------Original message----------------------------
>Hello All: I am hoping to build a soda kiln and I was wondering if I need to
>put extra silica sand in my clay to attract the soda. I used to do it when I
>did a lot of salt. I love to have a juicy salt build-up. Also, has anyone
>tried my CONE 6 ASH GLAZES that I posted.
>
>Capt. Mark Issenberg
Mark,
From my experience, you need a less silicous clay for soda than for salt.
Your clay body does not have to "attract" the soda....the soda will tend to
dump all its load on the first pots it hits, and ignore the others, unless
your clay has some resistance to the action of the soda. Soda doesn't
volatalise as easily as salt, and doesn't travel around the kiln as well, so
on one hand it does make sense to theorise that more silica in your clay
body would encourage more glaze formation. From practice, however, I can
tell you I get better results by increasing the alumina content, which makes
the soda react more evenly on all the pots in the kiln. To get colour and
orange peel texture, you will need a higher alumina:silica ratio in your
clay body and slips, than you would use for salt firing.
_______________________________
Gail Nichols
Sydney, Australia
gail@matra.com.au
http://www.matra.com.au/~gail/
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