Lily Krakowski on tue 3 jun 03
The archives will prove that whatever else I am I am consistent. 'Cause
nothing has HAPPENED to change my mind.
1. As mined products, NONE of our materials are 100% consistent over the
decades. (And if we ain't talkin'decades who cares?) A conversation with
the wonderful Mr Isaacs of Hammill and Gillespie years ago taught me that
many feldpars sold under trade names are actually blends made to conform to
certain formulae. The advantage of frits is that they are controlled to
remain the same. Fine.
So while ulexite may be closer to GB than any frit--I have yet to see it in
a regular pottery catalog.(Talking US here)
Books DO simply say "calcium borate frit" and some say GB or "calcium borate
frit." WHY DO THEY SAY IT?
Because any potter who TAKES the time can figure it out. Yes, you all
should learn to do formulae, and, having just gotten it (MY FIRST!!!) John's
Glaze Master works swell, even with one hand tied behinds one's back (in my
case,one hand bandaged!)
GB is a natural mix of 1 part calcium to 1.5 parts Boron. DUH!!!!!!
It has 5 molecules of water (DUH!!!!! again.) To make a glaze GB has clay
and silica added to it, and in many recipes there is another flux provider,
at c. 6 generally/frequently Neph. Sy.
Now if one uses a frit one looks at the formula and says: Gee whiz there is
SO much boron and SO little calcium and there already IS alumina and silica.
Wot's a gull to do?
One thing to do is to say Gee whiz--lookit: Frit 3195 has just about TWO
parts boron to 1 part calcium, and frit 3124 has a tidge MORE calcim than
boron, and 3134 has just about the same amount!
NOW WHY CAN'T YOU DO HERE WHAT YOU DO IN THE KITCHEN, PRAY TELL? There you
say, well, if I am going to use soy sauce, I better not use salt-- What is
the problem when that comes to glazes???? in the kitchen you can taste. In
the studio you need to test.
You say well, there is lots of calcium coming in from another source so I
will "satisfy" the boron...And take an educated guess or do a blend. And if
you get more alumina and silica from the frit than you want, you cut back on
the alumina/silica that you get from another source.....
AS TO CONVERTING. Can you convert tweed to cotton? Can you convert silk to
linen? Of course not. C. 10 glazes have c. 10 characteristics achieved
mainly by the fact that some fluxes are "available"at c. 10 which are not
useful at c. 6. Before you weep, just remember that the lovely lead glazes
we used to use all are GONE. And, never were "convertible"to high temps.
Clutch a sample of the glaze you love. Then holding it in your hand look at
samples of existing c. 6 glazes. See what is in the same SPIRIT...Forget
conversion.
A HINT: magnesium, tin, and mixes of titanium and tin can give calcium
borate glazes that gentler kinder look. So can teensy amounts of colorants,
just enough to soften, to dull....
Lili Krakowski
P.O. Box #1
Constableville, .Y.
(315) 942-5916/ 397-2389
Be of good courage
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