Veena Raghavan on sun 26 aug 07
A request to the our glaze gurus,please.
Would this glaze be considered foodsafe at cone 9-10 in reduction.
Thanks in advance.
Veena
VCAA Green ^9-11R or oxidation Val Cushing
Cornwall Stone 46
Whiting 34
EPK 20
Copp Carb 4
Tin 4
VeenaRaghavan@cs.com
John Hesselberth on mon 27 aug 07
On Aug 26, 2007, at 10:38 PM, Veena Raghavan wrote:
> Would this glaze be considered foodsafe at cone 9-10 in reduction.
>
> VCAA Green ^9-11R or oxidation Val Cushing
>
>
> Cornwall Stone 46
> Whiting 34
> EPK 20
> Copp Carb 4
> Tin 4
Hi Veena,
Not by me. I wouldn't serve or store food on it. It is way low in =20
silica and has a copper level that only the most well formulated =20
glazes will hold. Here is the unity formula:
Regards,
John
------------------
Recipe Name: VCAA Green
Cone: 9-11 Color: Green
Firing: Ox. or Red. Surface: Matte
Amount Ingredient
46 Cornwall Stone
34 Whiting
20 Kaolin--EPK
100 Total
Additives
4 Copper Carbonate
4 Tin Oxide
Unity Oxide
.069 Na2O
.047 K2O
.007 MgO
.878 CaO
1.000 Total
.363 Al2O3
.004 Fe2O3
1.777 SiO2
.003 TiO2
.004 P2O5
4.9 Ratio
81.5 Exp
Comments:
-----------------------------------
Calculations by GlazeMaster=99
www.masteringglazes.com
------------------------------------
John Hesselberth
www.frogpondpottery.com
"Man is a tool-using animal....without tools he is nothing, with =20
tools he is all" .... Thomas Carlyle
claystevslat on mon 27 aug 07
Veena --
I'm not especially conversant with high-fire glazes,
but it's very low in silica and rather high in copper.
I'd want to do several acid tests on this glaze over
different clays before I'd be willing to take a chance
on having someone use it in the kitchen.
Depending on how you look at it -- unity or molar --
it's also either normal or not normal for alumina. (It's
high if you use molar, normal if you use unity.)
But you know there's nothing like making a piece with
a glaze on it and testing it in real-life conditions
to find out how it responds. Some glazes that look
risky do hold up no matter what you do to them. Others
don't, even if the recipe looks fine.
Best wishes -- Steve Slatin
--- In clayart@yahoogroups.com, Veena Raghavan
wrote:
>
> A request to the our glaze gurus,please.
>
> Would this glaze be considered foodsafe at cone 9-10 in reduction.
>
> Thanks in advance.
>
> Veena
>
> VCAA Green ^9-11R or oxidation Val Cushing
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