Lili Krakowski on thu 9 sep 04
Antoinette et al.
I have no idea whether dolowhite is dolomite by another name. It =
really does not matter.
What does matter is this: that our materials are MINED, and that not =
only do mine runs from the same dear old mine vary, but some materials =
are mined in different places in the world. Therefore their composition =
will vary. Therefore a recipe from Australia or Turkey, or Belgium =
calling for Neph Sy or Cornwall Stone or whatever MAY have a different =
analysis and unexpected results when tried "at home."
That is why my friend Hob (Mr Goblin of Small Minds, NY) always tells =
students: 1. Whenever a new material comes into the studio--by which =
is meant a new supply, even if from same supplier--segregate a small =
amount (a pint or so) and mark clearly with provenance, date, etc. KEEP =
IT. 2. Whenever a batch of new material comes into the studio --a new =
supply whether from same supplier as "always" or not, make a comparison =
test with the old batch of glaze. I.E. make a test tile of the glaze =
made with the NEW supply and compare with the glaze you have been using. =
3. Always keep a small amount of any material if it is about to go off =
the market. I still have some GB and use it to compare to glazes made =
from recipes new to me, which contain GB, but where I have to replace =
with a boral frit. I still have Oxford Spar, and other spar samples for =
the same reason.
I know that now materials come escorted by information sheets. Probably =
those mean a lot to people like Ron, John, Ivor, Tom, Edouard, Steve and =
some others. They mean little to me because I cannot figure out without =
testing whethere a small variation in impurities, or a small difference =
in the % of the less important materials will/will not affect my glaze. =
I test.
A good--if bitter--laugh. As a student I mixed up a glaze that turned =
out gorgeous. I wanted to make more, and did. It turned out ugly. =
Perhaps now I could figure out what went wrong. Probably I had grabbed =
a container of X when I wanted Y. But at the time I did not have a =
clue. And it was only years, heck, decadeslater, that I realized I may =
not have made a mistake AT ALL. That a raw material may have been from =
a new supply, and just different enough from what we had used to affect =
the result. Now I would "know" how to proceed. Then I didn't. Ah, =
well.
Lili
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