Josh Lynch on wed 16 jun 99
At schoolI made a 100 gram batch of WG white ^6.
Custer feldspar 34.48
Gerstley borate 11.49
Zinc oxide 11.49
Dolomite 17.24
Flint 25.29
It was transparent very fluid with streaks of white. I came home,
tested the same 100 gram batch in my own kiln, it was no difference.
So I made a 500 gram batch to run color tests on it.
It was completely different. Still white, but covered with a matrix of
buttery feeling crystals. The color tests came out -- burgundy with
blue background is my fav. I did this twice, while making absolutely
sure I didn't mis-measure. At first it felt like a mg matte to me.
Tried doubling the dolo to no avail. It looks like zinc crystals.
At school the zinc was a hassle to get through a seive. It was gray
and granular. The zinc I bought from Standard is white, hint of yellow
fluffy powder.
Thanks, josh -- west va
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Tom Buck on fri 18 jun 99
So, Josh Lynch, you got a Bristol type glaze that verges on being a zinc
crystalline glaze. The Seger Formula is as follows:
WG White C6 Ox
CaO 0.32 B2O3 0.10 SiO2 1.98
MgO 0.22 Al2O3 0.15
KNaO 0.14
ZnO 0.33 SiO2/Al2O3 = 12.9 COE (Expansion)= 7.1x10-6
The Zinc Oxide is above the usual molar amount in a Bristol glaze.
Other distinctions: Low CaO and high MgO; low Al2O3, low SiO2 for
a C6 glaze. If the MgO were lower this mix would flow off the pot.
You ask a question or two but I am unable to be sure what you want
to know. If you tell me what precisely you expect to achieve from this
mix, perhaps I can fix it. Til later. Tom.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
On Wed, 16 Jun 1999, Josh Lynch wrote:
> ----------------------------Original message----------------------------
> At schoolI made a 100 gram batch of WG white ^6.
> Custer feldspar 34.48
> Gerstley borate 11.49
> Zinc oxide 11.49
> Dolomite 17.24
> Flint 25.29
> It was transparent very fluid with streaks of white. I came home,
> tested the same 100 gram batch in my own kiln, it was no difference.
> So I made a 500 gram batch to run color tests on it.
>
> It was completely different. Still white, but covered with a matrix of
> buttery feeling crystals. The color tests came out -- burgundy with
> blue background is my fav. I did this twice, while making absolutely
> sure I didn't mis-measure. At first it felt like a mg matte to me.
> Tried doubling the dolo to no avail. It looks like zinc crystals.
>
> At school the zinc was a hassle to get through a seive. It was gray
> and granular. The zinc I bought from Standard is white, hint of yellow
> fluffy powder.
>
> Thanks, josh -- west va
>
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at http://mail.yahoo.com
>
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