Tom Buck on thu 27 nov 97
When Ms Storer asked for an explanation of crystals forming in her glaze
slurry, it seemed to be an isolated case (although I have suffered through
this experience too when my basement studio got too cool). Now other have
asked for elaboration. So here is my spin on the problem, sans the Ionic
Language that Louis Katz mentioned.
Tom Buck ) tel: 905-389-2339
& snailmail: 373 East 43rd St. Hamilton ON L8T 3E1 Canada
(westend Lake Ontario, province of Ontario, Canada).
---------- Forwarded message ----------
Date: Tue, 18 Nov 1997 21:49:25 -0500 (EST)
From: Tom Buck
To: Terri Storer
Subject: Re: crystals precipitating out of glaze
Terri S: Chances are high that some of the raw materials are dissolving in
the water
and then recrystalling out again later. This is especially so for Gerstley
Borate; it is slightly soluble, and more so in warm water. Calcium
carbonate and Dolomite (CaCO3.MgCO3) are also very slightly soluble. But
the most soluble of all is Lithium Carbonate, 15 grams/litre (1000 grams
of water). So those crystals were probably LiCO3 + small amounts of the
others. What to do? Mainly try to keep the slurry at room temperature
and stir it daily. If crystals do form again, you repeat the screening,
grinding, etc. If this bugs you, you will have to switch to a lithium
feldspar (spodumene, etc.). BFN.
Peace. Tom.
Tom Buck ) tel: 905-389-2339 & snailmail: 373 East
43rd St. Hamilton ON L8T 3E1 Canada (westend Lake Ontario, province of
Ontario, Canada).
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