Lisa Goldberg on sat 12 jun 99
Sorry I forgot to list the cone for the blue / turquoise glaze I'm looking
for...the excitement of it all you know.
Lisa In Yellow Springs, OH
Pat Colyar on sun 13 jun 99
Lisa G., here's a reliable classic:
Weiser Turquoise Cone 10 Reduction
Custer Spar 63%
Dolomite 24%
Ball Clay 9%
Silica 4%
Add: Cobalt Carbonate 0.5%
and Chrome Oxide 1.5%
Good luck! Pat Colyar in Gold Bar, Washington
Liz Willoughby on mon 14 jun 99
Is this a safe durable glaze for functional ware? I'm thinking of the
chrome oxide. Ron? or Tom?
>----------------------------Original message----------------------------
>Lisa G., here's a reliable classic:
>
>Weiser Turquoise Cone 10 Reduction
>
>Custer Spar 63%
>Dolomite 24%
>Ball Clay 9%
>Silica 4%
>
>Add: Cobalt Carbonate 0.5%
> and Chrome Oxide 1.5%
>
>Good luck! Pat Colyar in Gold Bar, Washington
Liz Willoughby
R.R.# 1
2903 Shelter Valley Rd.
Grafton, Ontario
K0K 2G0
Canada
e-mail, lizwill@phc.igs.net
Tom Buck on wed 16 jun 99
Liz:
At first look the Weiser Turquoise (below) has the "shape" of an
ok glaze but the Seger Formula says otherwise. It would fire dry matt
simply because it lacks one great deal of Silica (& some Alumina). The
glaze if applied thinly on a pot might take up some silica from body and
be vaguely serviceable (but not food worthy). I say be wary of it as is.
One could "adjust" the notion of this glaze and offer the
following for firing anf leach-testing:
Lizzy's Blue Turq. C10R
32 G200 feldspar
16 Wollastonite
8 Talc new york
13 Ballclay (Old Mine#4 or equal)
16 EPKaolin (or equal)
14 Flint fine mesh
add 0.7 Cobalt Carbonate & 2 Chromium Oxide
This mix is a Calcia/Magnesia/Alumina matt and would approach a dryish
matt on some bodies, be satin matt on others, if fired to C10 or higher.
I believe this new version would hold the Co++ and Cr+++ ions
within its glassy matrix and hence not release any worrisome amounts of
these two ions, both toxic above a certain level (? 1 mg/mL, 1 ppm ?).
Perhaps you'd like to do the test firing, Liz? Til later. be well.
Peace. 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 Mon, 14 Jun 1999, Liz Willoughby wrote:
> ----------------------------Original message----------------------------
> Is this a safe durable glaze for functional ware? I'm thinking of the
> chrome oxide. Ron? or Tom?
>
>
>
> >----------------------------Original message----------------------------
> >Lisa G., here's a reliable classic:
> >
> >Weiser Turquoise Cone 10 Reduction
> >
> >Custer Spar 63%
> >Dolomite 24%
> >Ball Clay 9%
> >Silica 4%
> >
> >Add: Cobalt Carbonate 0.5%
> > and Chrome Oxide 1.5%
> >
> >Good luck! Pat Colyar in Gold Bar, Washington
>
> Liz Willoughby
> R.R.# 1
> 2903 Shelter Valley Rd.
> Grafton, Ontario
> K0K 2G0
> Canada
>
> e-mail, lizwill@phc.igs.net
>
Ron Roy on thu 17 jun 99
It is difficult to tell from the formula - it does have 60% silica and that
indicates it might be - the only way to tell for sure is to have it tested.
You may be sure that there is chrome volitizing during firing and that can
be a danger to those in the vicinity.
RR
>----------------------------Original message----------------------------
>Is this a safe durable glaze for functional ware? I'm thinking of the
>chrome oxide. Ron? or Tom?
>
>
>
>>----------------------------Original message----------------------------
>>Lisa G., here's a reliable classic:
>>
>>Weiser Turquoise Cone 10 Reduction
>>
>>Custer Spar 63%
>>Dolomite 24%
>>Ball Clay 9%
>>Silica 4%
>>
>>Add: Cobalt Carbonate 0.5%
>> and Chrome Oxide 1.5%
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
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