RubiaM&M on wed 2 feb 05
lou
try
48 Custer Feldspar
10 Gerstley Borate
6 Strontium Carb
18 Whiting
18 Flint
2% Bentonite
regards
rubia moraes
> Can someone with glaze software tell me if this base glaze is balanced
> for cone 6 electric
> and safe to use on functional ware? I would really appreciate it.
> Thanks
> Lou
>
> BASE GLAZE Cone 6 OX
>
> 38 Custer Feldspar
> 22 Gerstley Borate
> 4 Strontium Carb
> 11 Whiting
> 25 Flint
> 2% Bentonite
>
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Edouard Bastarache Inc. on wed 2 feb 05
Lou,
here is the score according to GlazeChem using
the Magic of Fire's limit formulas.
BASE GLAZE Cone 6 OX
38 Custer Feldspar
22 Gerstley Borate
4 Strontium Carb
11 Whiting
25 Flint
2% Bentonite
Na2O 0.16 Al2O3 0.32 SiO2 4.21
K2O 0.20 B2O3 0.44 Fe2O3 0.00
MgO 0.09
CaO 0.42
SrO 0.13
Alumina:Silica ratio is 1.00:13.31
Neutral:Acid ratio is 1.00:5.60
Alk:Neut:Acid ratio is 1.00:0.75:4.22
Expansion: 71.8 x 10e-7 per degree C
Oxides causing abnormal expansion:
B2O3 SrO
0.0 0.5 1.0
KNaO : |---;---;-*-;---| : : : : : 0.36
CaO : |---;---;---;*--;---;---| : : : 0.42
MgO |---*---;---| : : : : : : : 0.09
Li2O *---;---| : : : : : : : : 0.00
ZnO *---;---;-| : : : : : : : : 0.00
BaO *---;---;---| : : : : : : : 0.00
SrO |---;*--;---;---| : : : : : : 0.13
0.0 1.0 2.0
Al2O3 : |-*|: : : : : : : : : 0.32
B2O3 |---;---|o : : : : : : : : 0.44
0.0 5.0 10.0
SiO2 : : : |-;-| :o : : : : : : 4.21
* Means within the limit,
o Means outside the limit.
So you have a little extra boron to compensate for
the extra silica.
You will not know for sure until it "passes the test of fire"
But, I believe it should work.
Later,
"Ils sont fous ces quebecois"
"They are insane these quebekers"
"Están locos estos quebequeses"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
John Hesselberth on wed 2 feb 05
Hi Lou,
A lot of the answer to your question depends on the particular
composition of gerstley borate you are using. Using a 9/97 analysis I
have this glaze would be a little low on silica and a fair amount low
on alumina to be durable.
Using a 1999 analysis, it is much closer to being a stable glaze,
although it is still lower in alumina than I like to see.
This is why so many of us who do functional work avoid gerstley
borate--it is very variable in composition.
In either case, it is probably OK with no or very low levels of
colorants. However, higher levels of colorants, particularly copper,
would leach in significant amounts. The only way to be certain is to
have the glaze tested with your ingredients, applied the way you apply
it and fired the way you fire it.
Regards,
John
On Wednesday, February 2, 2005, at 06:54 PM, Lou Roess wrote:
> Can someone with glaze software tell me if this base glaze is balanced
> for cone 6 electric
> and safe to use on functional ware? I would really appreciate it.
> Thanks
> Lou
>
> BASE GLAZE Cone 6 OX
>
> 38 Custer Feldspar
> 22 Gerstley Borate
> 4 Strontium Carb
> 11 Whiting
> 25 Flint
> 2% Bentonite
>
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Lou Roess on wed 2 feb 05
Can someone with glaze software tell me if this base glaze is balanced
for cone 6 electric
and safe to use on functional ware? I would really appreciate it.
Thanks
Lou
BASE GLAZE Cone 6 OX
38 Custer Feldspar
22 Gerstley Borate
4 Strontium Carb
11 Whiting
25 Flint
2% Bentonite
David Hewitt on thu 3 feb 05
Using the analysis of the materials that I use, I get the following
results:-
Al2O3 - Recipe gives .461 mol parts in unity formula and B2O3 gives
.467. Both these are just above my upper limit.
SiO2 - Recipe gives 5.321 mol parts in unity formula which a
significantly above my upper limit of 3.5 for cone 6
David
In message , Lou Roess writes
>Can someone with glaze software tell me if this base glaze is balanced
>for cone 6 electric
> and safe to use on functional ware? I would really appreciate it.
>Thanks
>Lou
>
>BASE GLAZE Cone 6 OX
>
>38 Custer Feldspar
>22 Gerstley Borate
>4 Strontium Carb
>11 Whiting
>25 Flint
>2% Bentonite
--
David Hewitt
Web:- http://www.dhpot.demon.co.uk
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