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silica alumina glaze ratios?

updated fri 31 may 96

 

Linda Arbuckle on fri 24 may 96

Greetings,

Can anyone point me to references or information that would provide
information about interpreting the silica alumina ratio in glazes? I was
doing some glaze recalc on HyperGlaze and noticed the recommendations for
cone 03 glossy read that above 8:1 silica to alumina is recommended.

Thanks......
Linda
_______________________________________________
Linda Arbuckle E-mail: ARBUCK@nervm.nerdc.ufl.edu
Asst. Prof.
Univeristy of Florida
Department of Art 302 FAC
Gainesville, FL 32611 Ceramics: (352) 392-0228

June Perry on fri 24 may 96

Dear Linda:

I use abut 4 or 5 to one Silica to Alumina ratio for matts. Four will give a
drier matt.
I use a 6 to 8 for semi matts to satins.
I use 9 to 11 or even 12 ratio for gloss.

Bob Kavanagh on sat 25 may 96

Hi Linda

Please note the following references in answer to your question about
silica/alumina ratios:

Joseph W. Conrad. Advanced Ceramic Manual: Technical Data for the Studio
Potter (San Diego: Falcon Company Publishers, 1987) pages 110-112. ISBN
0-935921-06-0

David Green. A Handbook of Pottery Glazes (New York: Watson-Guptill
Publications, 1979), in particular pages 106-107, 121-123, 133-134. ISBN
0-8320-2181-5.

Tony Hansen. The Magic of Fire (Medicine Hat, Alberta: IMC Printers, 1995),
pages 38-39. (email tony hansen, author:thansen@mlc.awinc.com).

If there are further questions please get in touch.

bob kavanagh


>----------------------------Original message----------------------------
>Greetings,
>
>Can anyone point me to references or information that would provide
>information about interpreting the silica alumina ratio in glazes? I was
>doing some glaze recalc on HyperGlaze and noticed the recommendations for
>cone 03 glossy read that above 8:1 silica to alumina is recommended.
>
>Thanks......
>Linda
>_______________________________________________
>Linda Arbuckle E-mail: ARBUCK@nervm.nerdc.ufl.edu
>Asst. Prof.
>Univeristy of Florida
>Department of Art 302 FAC
>Gainesville, FL 32611 Ceramics: (352) 392-0228

Ron Roy on sat 25 may 96

Hi Linda,

The simple explanation as I understand it is: If the ratio of SiO2 to Al2O3
is below 5 then you will probably have a matt glaze - unless you have B2O3
as well. Between 5 and 10 you probably have different degrees of semi gloss
and semi opake. Above 10 SiO2 to 1 Al2O3 the chances are you have a
transparent gloss glaze. There are exceptions of course. The trick to
keeping the character of a glaze while lowering or raising the maturing
temperature is to keep the ratio the same. This works fairly well with
balanced glazes but not as well with glazes outside recommended limits for
durable glazes.

Ron Roy, Toronto, Canada