Lily Krakowski on tue 22 apr 03
The reason I sometimes put out "Newbie alerts" is because there are people
out there, wonderful, generous people, who teach clay in diverse "centers"
and the like,and have neither time nor real interest in the technical
aspects of our materials. I think we owe them warnings, because they may
see a nice sounding recipe, and the materials may be on hand at their
"center" ....It is not obvious that Spodumene contains lithium...
As to lithium. Monona Rossol writes it is irritating to eyes, skin,
respiratory system. Absorption can cause symptoms from [mild like fatigue,
dizziness] to more serious complications [even coma and death] "Lithium
carbonate is used medicinally to control manic depressibe personality
disorders which demonstrates that even milligram amounts can cause effects.
Reproductive hazard." This from the second edition, revised and updated of
The Artist's Complete Health and Safety Guide.
I still and will forever maintain that the first clay book ANY newbie needs
is a book on studio health and safety. There are several. Get the latest.
Get a new one every few years as new ones appear.
As to risk taking; as to being over careful. Personal decisions. One can
only give out knowledge.
RAW GLAZING: I do it, because it fits in with my work. I often glaze
using a brush, with the pot on the wheel, after trimming. As I have serious
hand damage it is an easier glazing technique. I DO NOT ONCE FIRE as a
rule. This sounds odd, but it is easier for me to bisque, not only because
of the way I work with slips etc. BUT because I find that it is worth the
extra cost not to have to chip glazed chards off the shelves if a pot
oversags, or breaks; or if a pot cracks.
According to Dennis Parks'excellent book Carl Judson says raw glazes
--glazes applied to unfired pots--should have 40%-50% ball clay. If that is
lacking, adding 8-13% bentonite, replacing even all of kaolin if need be.
Bill Creitz says about 12% ball clay, and or Bentonite for a total of 24.
If need be, replace feldspar with Bentonite.
Ceramics Monthly says 3% Bentonite makes most glazes workable on greenware,
and an open body is better than a tight one.
In my own limited experience (I don't do that much) glazing leatherhard
pots, I find bentonite additions (test) work perfectly well. I doubt I've
ever needed more than 5%. My suggestion would be that if you have a glaze
and want to try it raw, make up a batch and add 3,4,5 percent bentonite to
100 gram sub-batches and test. You'll be surprised how easy it is.SOMEONE
LIKE RON WOULD HAVE TO TELL YOU IF THIS CHANGE MIGHT AFFECT STABILITY....
Lili
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
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