sharon miranda on sat 20 mar 04
Geez, thanks for all those great responses. I hope Don Kopyscinski does=20=
not mind that I quote his e-mail to me off the list, but I thought it=20
really might interest others:
"I have heard of people placing the crystals in some water and boiling=20=
them until the crystals are dissolved. This way=A0you are not losing the=20=
component that is crystallizing out. The cause is as usual, a=20
supersaturated solution. More material has dissolved than can be=20
maintained in solution. The warmer the water, the more solute it can=20
hold. If the glazes have gotten cooler than they were before, this will=20=
speed the formation of the crystals. This fix isn't a permanent one, as=20=
the component will again begin to crystallize any material in excess if=20=
it's saturated state at any given temperature.
=A0=A0=A0 The process may also be caused if you were to make your glazes =
with=20
hot water. Any solutes would dissolve. As the glaze cooled, it wouldn't=20=
be able to hold as much and the crystal growing process will begin.
=A0=A0=A0 The root cause is that lithium carbonate is slightly soluble.=20=
Supplying the lithium from another source would solve the problem. Of=20
course adjustments of the recipe are in order to maintain the same=20
balance of basic glaze components."
In answer to some of your questions:
the cobalt is carb.
I use this glaze only on the outside of pots. It's a glaze that I got=20
from Sandi Pierantozzi, and I don't know why it doesn't add up to 100.
I live in mortal dread of hearing that the glazes I use don't pass any=20=
kind of test....
This is a beautiful glaze - I use it in 3 colors: green (copper carb) ,=20=
gold (yellow iron oxide) and cobalt. It does not run, maybe because I=20
only fire to 05.
The reason I know it was lithium that caused the crystals is that the=20
green version of this glaze does NOT get lithium, and therefore did not=20=
get the crystals. (And I called a commercial lab as well, they take the=20=
credit for that piece of wisdom, not me).
Yes, I store my glazes in a cold (around 30-40 degrees F) garage...I=20
kinda thought that might be a reason.....
I wish I knew more about glazes and how they work, and yes, I've read a=20=
lot and tried to learn it by myself. I need another lifetime, I'm=20
afraid....
But thanks- I'm going to try all those suggestions- including the=20
reformulation...
Sharon
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