Donald G. Goldsobel on sun 5 oct 03
Blue Green Black ^10 Red. Per Jack Troy
I had this in the pile of glazes to try. I beleive it was from Clay Times
Sept\Oct '00 He comments it is very application and thickness sensitive.
Let me know how it comes out.
Cornwall stone 46
Whiting 34
EPK 20
Copper carb 4
Tin ox 4
Recommending "iron underneath"
Donald
Dave Finkelnburg on sun 5 oct 03
Donald,
And others who try this glaze...
This is not what I would expect to be a food-safe glaze. I have not
tested it, but this glaze is low enough in silica to be a matt, high enough
in copper that some will likely precipitate as black metal if this glaze is
fired in reduction. The copper will likely leach from the glaze.
The Seger or unity molecular formula I calculate is:
.88 moles CaO
.01 Moles MgO
.05 Moles K2O
.06 Moles Na2O
.37 Moles Al2O3
1.78 Moles SiO2
NOTE: I have only included the first four oxides in the flux portion, but
copper does also act as a flux, so this is effectively lower in alumina and
silica. At cone 10 this may run.
Good glazing,
Dave Finkelnburg
----- Original Message -----
From: "Donald G. Goldsobel"
> Blue Green Black ^10 Red. Per Jack Troy
> I had this in the pile of glazes to try. I beleive it was from Clay Times
> Sept\Oct '00 He comments it is very application and thickness sensitive.
> Let me know how it comes out.
>
> Cornwall stone 46
> Whiting 34
> EPK 20
>
> Copper carb 4
> Tin ox 4
>
> Recommending "iron underneath"
Ron Roy on tue 7 oct 03
With SiO2 at only 1.78 mols this is going to be a very unstable glaze - I
would think just about anyone would be able to taste the copper if orange
juice was beside this glaze for a very short time.
Try a lemon slice on it over night - at room temperature.
Definitly not a liner glaze.
RR
>Blue Green Black ^10 Red. Per Jack Troy
>I had this in the pile of glazes to try. I beleive it was from Clay Times
>Sept\Oct '00 He comments it is very application and thickness sensitive.
>Let me know how it comes out.
>
>Cornwall stone 46
>Whiting 34
>EPK 20
>
>Copper carb 4
>Tin ox 4
>
>Recommending "iron underneath"
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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