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runny crystalline glazes

updated tue 31 dec 96


Marcia Selsor & Matt Benacquista on sat 7 dec 96

Dear April,
Crystalline glazes have to be that runny to form crystals. The way to
fire them according to an Art Nouveau artist, was as follows:
Bisque fire to ^10
apply glaze thickly with gum arabic added for adhesion
cut a soft brick to fit the foot and wash it well with kiln wash
put the pot and brick in a bowl for the glaze cycle
chisel the brick off after the firing
grind the bottom with silicon carbide
The high bisque assures the pot won't shrink on the brick. I used this
method successfully for several years, but I got tired of the whole
process. I prefer saggar firing and raku or just plain old stoneware
pots. I still work in porcelain but with reds and celedons mostly.
Good luck. I did my MFA thesis on crystalline glazes. I found good
research material in the U of Illinois Ceramic engineering library
(hand written experiments from early 1900's and many articles in the
main library on Adelaide Robineau and Taxile Doat, both worked at the
Women's University in St. Louis for a while. Good luck. I ate a hole in
a brand new electric kiln floor the first time I fired crystalline
glazes. It is caustic stuff.
Marcia in Montana wrote:
> ----------------------------Original message----------------------------
> Hello, I found this great crystalline glaze recipe, but the
> only problem is that it is VERY runny. Is there anything
> I should add to the recipe or anything I can do to the
> shelves. I've been adding thick layers of kiln wash on the
> shelves but the glaze still seems to seep through. Thanks.
> April

Marci Selsor
Matt Benacquista

Rick Sherman on sun 8 dec 96

Greetings Marcia and Alice: The method for controlling runny
crystalline glazes as described by Marcia is one approach and was used
by my teacher, Dr. Herbert H. Sanders. See his text, "Glazes for
Special Effects," Watson-Guptill, 1974. Another approach is to make a
cylinder with a gutter running outside its base to capture the glaze.
Make it to fit just inside the trimmed foot of the pot. Use kiln wash
so it does not stick to the pot. The only grinding you do is on the
glaze. Jerry Meek, a teacher at San Jose State and now in Hawaii made
magnificent crystalline glazes and claimed he had found no need for
them to be so fluid. He did very little grinding.
Alice, prepare yourself for hours of experimenting and exploring.
Crystals can be challenging and addictive. RS