Randy McCall on thu 1 jul 04
Volcanic Ash 25%
GB 25%
3134 10%
Custer Feld 10%
Kaolin 10%
Silicia 10%
Wollastonite 10%
100%
When tested to Cone 6 I got a nice smooth shiny clear glaze. Smooth to =
touch.
Any comments on stability, expansion, etc? Combination of two glazes to =
make one.
Randy McCall
Ron Roy on sun 4 jul 04
Hi Randy,
I used the analysis for Mount St Helen's ash and the later analysis for GB.
It looks OK that way - enough silica and alumina and the expansion is right
for many cone 6 clays.
Your supplier may have an analysis for the ash - you should try to get it -
I can give a much better opinion if I have that.
If you are using "fresh" ash (not weathered) you may have some soluble
sodium to deal with. That makes it hard to stop crazing, degrades the glaze
because the sodium is lying on the surface (sodium is very soluble in
acids) and will affect the glaze slop - it can flocculate or deflocculate
depending on how much sodium there is.
You can always add 5% copper and send it to a lab - that will tell you
right away.
RR
>Volcanic Ash 25%
>GB 25%
>3134 10%
>Custer Feld 10%
>Kaolin 10%
>Silicia 10%
>Wollastonite 10%
> 100%
>
>When tested to Cone 6 I got a nice smooth shiny clear glaze. Smooth to touch.
>Any comments on stability, expansion, etc? Combination of two glazes to
>make one.
>Randy McCall
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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