Kim Marie on sun 4 jun 00
Hi All!!
I am struggling with glaze chemistry and the like... Here's my ?
I noticed that on the mason stain chart that there are stains that they =
recommend finding a glaze without zinc oxide. Seem to be especially the =
rosey colors. How come? Does this mean the stain can't work if the =
oxide is present?/
Kim Marie=20
In Central NY where we finally got 2 days hooked together without rain =
after 21 in row that did!!
info@kimmariefinepottery.com
www.kimmariefinepottery.com
thansen@DIGITALFIRE.COM on tue 6 jun 00
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> I am struggling with glaze chemistry and the like... Here's my ?
> I noticed that on the mason stain chart that there are stains that they =
> recommend finding a glaze without zinc oxide. Seem to be especially the =
> rosey colors. How come? Does this mean the stain can't work if the =
> oxide is present?/
Correct. In ceramics color is a matter of chemistry, not blending.
For a stain to produce the intended color it has to be put into a host
glaze with a sympathetic chemistryt. Zinc is needed to get certain colors
with certain metal oxides and is hostile in others. Almost every oxide is
implicated is one 'color system' or another, even silica and alumina.
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T o n y H a n s e n thansen@digitalfire.com
http://digitalfire.com Calculation/Database Software for Ceramic Industry
http://ceramicsearch.com Search engine for the Ceramic Industry
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Craig Martell on tue 6 jun 00
Kim asked:
>I am struggling with glaze chemistry and the like... Here's my ?
>I noticed that on the mason stain chart that there are stains that they
>recommend finding a glaze without zinc oxide. Seem to be especially the
>rosey colors. How come? Does this mean the stain can't work if the oxide
>is present?/
Hi:
The rosey colors that you talk about are most likely chrome-tin pinks,
reds, etc. The development of the color with these oxides is not favored
by the presense of zinc. It's important too that the base glaze contain
calcium from whiting, wollastonite, or some other source. I don't remember
the molar equivalents for calcium in a chrome tin glaze but usually about
15% whiting in the receipe will do it.
regards, Craig Martell in Oregon
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