Alisa and Claus Clausen on sun 18 jun 00
Dear Ron,
I wrote to my supplier with the makeup of Frit 3134, which I got from =
Tom B. earlier. So there was no panic!
The supplier came back with the idea that I just add to Gerstley Borate =
the missing amounts and sort of make it up to frit 3134. After looking =
at the two formulas, it finally (better late then never) crashed over me =
like a sunny day in Denmark, why you are busy substituing frit 3134 for =
Gerstely Borate.
I may have the last strong hold of Gerstely Borate in Denmark. My =
supplier got all he could from the ceramic importer and that was 23 =
kilos. I am striving of course to only use it up in raku, and not in =
glazes I plan to=20
use as committed base glazes.
I have given up Marek's recipe for the clear, because I have just had =
really good results with what I will call
"Doug's easy clear". I mistakenly posted it to you to add up only to =
88,
the correct receipe is=20
Gerstely Borate 50
Silica 32,5
Kaolin 17,5
have also seen it as
Gerstely Borate 48
Silica 30
Kaolin 22
I just removed tests with the the first quantities and all three results =
were very nice. Very smooth, shiny and even .
Over my usual clay body, a light grey cone 6-8 stoneware
Over my slip very fluid, no crackling and no shivering
Over other glazes I regularly use pulled up colbalt and =
softened the tenmokus
NOW, if we could find a way to get out the Gerstely Borate here, but I =
just do not think we have any frits that even look like 3134.
Available only are
alkali frit which is white covering, has 3,275 SiO2 and only 0,935 B2O3
2 raku frits, one is for crackling
Crystal frit, no born, 1,900 SiO2
Lithium frit. No
You of course can better tell me, but none of them look good. No use =
adjusting Gerstely Borate, because the idea is not to use the material.
The supplier sells a perfectly good clear glaze ready prepared, which I =
have also used in 90% with 10% matt clear to get a silk that I like. =
Cannot get that receipe, but may have to continue using it and coloring =
it.
I got a very good result with adding 15% ocher. Would that be all right =
for a liner glaze or is it not food safe with that percent?
Best regards,
Alisa in Denmark
Ron Roy on wed 21 jun 00
Hi again Alisa,
Tell your supplier - it is impossible to make GB into 3134 - GB has MgO and
alumina in - niether of which is in 3134 - you can't take them out.
What you are looking for in a frit - 20 to 30% boron - little or no alumina
- I can't believe there is no one using born frits over there - look under
ceramics etc in the phone book - Ferro might have a number as well - ask
them where they get their frits - then pone and ask if they will sell you a
bag.
Can you get the name or the analysis for the two Raku frits - they might work.
I don't think Ochre is a problem - the analysis I use has no toxins but it
is a variable material - some kinds may have some Manganese which is not a
problem for the user of the glaze. It can be a problem for the maker
however.
RR
>I wrote to my supplier with the makeup of Frit 3134, which I got from Tom
>B. earlier. So there was no panic!
>The supplier came back with the idea that I just add to Gerstley Borate
>the missing amounts and sort of make it up to frit 3134. After looking at
>the two formulas, it finally (better late then never) crashed over me like
>a sunny day in Denmark, why you are busy substituing frit 3134 for
>Gerstely Borate.
>
>I may have the last strong hold of Gerstely Borate in Denmark. My
>supplier got all he could from the ceramic importer and that was 23 kilos.
>I am striving of course to only use it up in raku, and not in glazes I
>plan to
>use as committed base glazes.
>
>I have given up Marek's recipe for the clear, because I have just had
>really good results with what I will call
>"Doug's easy clear". I mistakenly posted it to you to add up only to 88,
>the correct receipe is
>Gerstely Borate 50
>Silica 32,5
>Kaolin 17,5
>
>have also seen it as
>Gerstely Borate 48
>Silica 30
>Kaolin 22
>
>I just removed tests with the the first quantities and all three results
>were very nice. Very smooth, shiny and even .
>Over my usual clay body, a light grey cone 6-8 stoneware
>Over my slip very fluid, no crackling and no shivering
>Over other glazes I regularly use pulled up colbalt and
>softened the tenmokus
>
>NOW, if we could find a way to get out the Gerstely Borate here, but I
>just do not think we have any frits that even look like 3134.
>
>Available only are
>alkali frit which is white covering, has 3,275 SiO2 and only 0,935 B2O3
>2 raku frits, one is for crackling
>Crystal frit, no born, 1,900 SiO2
>Lithium frit. No
>
>You of course can better tell me, but none of them look good. No use
>adjusting Gerstely Borate, because the idea is not to use the material.
>
>The supplier sells a perfectly good clear glaze ready prepared, which I
>have also used in 90% with 10% matt clear to get a silk that I like.
>Cannot get that receipe, but may have to continue using it and coloring
>it.
>I got a very good result with adding 15% ocher. Would that be all right
>for a liner glaze or is it not food safe with that percent?
>
>Best regards,
>Alisa in Denmark
>
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>
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Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Ken Chin-Purcell on wed 21 jun 00
Alisa,
Ron Roy replied:
> What you are looking for in a frit - 20 to 30% boron - little or no alumina
> - I can't believe there is no one using born frits over there -
PotteryCrafts and Potclays in England both supply calcium borate frits
that act as a fritted substitute for Colmanite and fit the description
above. I just ordered some from Ulster Ceramics in Londonderry. I seem
to remember that you have access to Potclays materials, so you should also
be able to order some.
-- Ken Chin-Purcell (Tipperary, Ireland)
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