Edouard Bastarache on tue 24 sep 02
Question for "cone sixers":
"Perhaps you could answer a question for me.
=20
I have read that the Alumina - Silica ratio for a stoneware glaze should =
be in the range of 9 or 10.
=20
I fire at cone 6 and several cone 6 glaze recipes I have checked do not =
have a ratio that high (I know that matte glazes have a lower ratio to =
make them matte).
=20
Is there a lower "ideal" Alumina - Silica ratio for cone 6 (glossy)?
=20
=20
Thanks,
=20
Rich Read ..."
Here is my answer:
Hello,
I am not a "cone sixer" but I have checked limit formulas published by =
experts.
I have 2 propositions to make:
1- Alumina=3D0.2 to 0.3
Silica=3D2 to 3
2-Alumina=3D0.1 to 0.3
Silica=3D1.5 to 4
As you may see the 10-fold principle (silica/alumina) seems to apply =
also at C/6 also.
I will send your request to a 3,000 potter newsgroup and see what they =
have to say.
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
=20
Ababi on tue 24 sep 02
I did not answer this question because the question was too simplified. I could say ;
Yes it is true but what about this silky matte glaze?
My version to a well known glaze:
EMILY'S PURPLE 2
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 6 1201 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
BALL CLAY AK 21.65
TALC 12.64
Dolomite 10.00
Laguna Borate 5.91
FRIT F-4 23.74
Calcium Carbonate 0.81
SILICA 16.10
ULTROX 9.09
Cobalt Oxide 3.00
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.202 5.62%
CaO 0.331 7.06%
MgO 0.467 7.17%
Al2O3 0.278 10.78%
B2O3 0.217 5.75%
SiO2 2.473 56.60%
ZrO2 0.145 6.78%
TiO2 0.008 0.24%
K2O 0.069 2.46%
Na2O 0.134 3.16%
Al:Si 8.91
Expan. 6.38
ST 363.68
Don't look for this frit , it is an Italian frit.
Just to show that mainly you are right but there are other factors like flux-colorant
oxides or a lot of magnesia ( in this glaze)
So my answer is Yes, it can be but...
Ababi Sharon
Glaze addict
Kibbutz Shoval Israel
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
---------- Original Message ----------
>Question for "cone sixers":
>"Perhaps you could answer a question for me.
>
>I have read that the Alumina - Silica ratio for a stoneware glaze should be in the
range of 9
>or 10.
>
>I fire at cone 6 and several cone 6 glaze recipes I have checked do not have a ratio
that
>high (I know that matte glazes have a lower ratio to make them matte).
>
>Is there a lower "ideal" Alumina - Silica ratio for cone 6 (glossy)?
>
>
>Thanks,
>
>Rich Read ..."
>Here is my answer:
>Hello,
>I am not a "cone sixer" but I have checked limit formulas published by experts.
>I have 2 propositions to make:
>1- Alumina=0.2 to 0.3
> Silica=2 to 3
>2-Alumina=0.1 to 0.3
> Silica=1.5 to 4
>As you may see the 10-fold principle (silica/alumina) seems to apply also at C/6
also.
>I will send your request to a 3,000 potter newsgroup and see what they have to say.
>Edouard Bastarache
>Irreductible Quebecois
>Indomitable Quebeker
>Sorel-Tracy
>Quebec
>edouardb@sorel-tracy.qc.ca
>http://sorel-tracy.qc.ca/~edouardb/
>http://perso.wanadoo.fr/smart2000/index.htm
>
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