Tony Hansen on mon 2 jun 03
This frit is certainly not a substitute for Gerstley
Borate. Check www.gerstleyborate.com for more info.
They do have something in common however, they both
source boron and in many glazes using calculation you
can work the frit in. However in other glazes it is
very difficult or impossible to use this frit. There
is a detailed lesson in the INSIGHT manual comparing
the use of this frit with Turkish Ulexite showing how
the latter is far superior as a sub. The latter material
is available in many places in the world, it is used
in the fiberglass industry as a flux.
-------8<--------
I was certainly surprised to read this article and see that it is with a =
published cone 6 recipe where Gerstely Borate is used (24%) OR it says, =
Firt 3134.
Here is the recipe
43 Neph. Syenite
24 G.B. or Frit 3134
9 Zinc Oxide
5 Kaolin
5 Rutile
1 Cobalt Carb.
I am very curious as to why this can be cited as a substitute for =
Gerstely Borate?. Is it because it gives the flux/melt needed like my =
Frit, but after analysis, can it really be used as a suitable sub.? If =
so, is this a new finding? =20
--------
Tony Hansen, Digitalfire Corp.
Tony Hansen on mon 2 jun 03
I agree whole heartedly, this is totally misleading.
What does \"boron frit\" mean anyway. This is like saying
a \"silica glaze\". All glazes have silica and most frits
have boron. Do they mean one
that contains 1% boron or 50% boron. Doesn\'t it matter
what else is in the frit? Of course it does. Even if
these sources said \"calcium borate frit\", this still
is not specific enough, there is a huge range of such
frits.
-------8<--------
And I have also seen the recipes with an asterisk after the GB,
with a note to substitute a boron frit.
--------
Tony Hansen, Digitalfire Corp.
Alisa Clausen on mon 2 jun 03
Dear Clayart,
I am refering to an article in
Pottery Making Illustrated, May/June 2003.
Article by Maria Spies "How to make a rattle mug". Just got my copy.
About three years ago when I started making glazes with the Danish =
materials at hand, I tested many glazes that included G.B. and used =
Colemanite as a weight for weight sub. All in the archives. Some of the =
first tests I made. Turns out G.B. is available in abundance anyway. =
The tests with Colemanite in general showed a muddier glaze and after 20 =
percent, not the same glaze. Rotten results.
Instead of using Gerstely Borate, what could I use when a recipe called =
for larger percents than 20?. No Boraq or other like materials here =
yet. I was looking for a flux, a source of Boron, and after reading all =
the analysis of materials around me, I tried the frit I frequently used, =
623. Not scientific, a very loose understanding of the material I was =
looking for. My thought was more or less, well, there is at least Boron =
in the Frit. It has 28.5% Boron, but drags along a lot of Silica plus =
Zinc and Barium. Give it a try. The glazes look good. But I know that =
this was sort of well, not the correct thing to do. It is not the answer =
for a really suitable sub. for G.B. But as said, short of the things it =
drags with it, the Frit gives me good glazes. Thank you glaze gurus for =
being politely silent on my use of this Frit. Ron Roy and I have talked =
about it and he has and is helping me to revise some glazes still using =
my Frit. In fact, I may have overlooked a frit available here that more =
closely resembles 3134, no zinc, no Barium. Next slew of tests.
I was certainly surprised to read this article and see that it is with a =
published cone 6 recipe where Gerstely Borate is used (24%) OR it says, =
Firt 3134.
Here is the recipe
43 Neph. Syenite
24 G.B. or Frit 3134
9 Zinc Oxide
5 Kaolin
ADD
5 Rutile
1 Cobalt Carb.
I am very curious as to why this can be cited as a substitute for =
Gerstely Borate?. Is it because it gives the flux/melt needed like my =
Frit, but after analysis, can it really be used as a suitable sub.? If =
so, is this a new finding? =20
Very curious,
Alisa in Denmark
Mert & Holly Kilpatrick on mon 2 jun 03
Alisa,
I also have noticed recent articles in ceramics magazines quoting recipes
with Gerstley Borate, and I wonder why they choose to publish them, since it
is unrealistic for people to spend much time working on developing GB
glazes. And I have also seen the recipes with an asterisk after the GB,
with a note to substitute a boron frit.
I think many of us who have worked on converting GB glazes would attest
that, while the recipe with a boron frit may make a glaze, may even make a
NICE glaze, it is very common that it will NOT make the glaze discussed in
the article. Especially without altering the rest of the glaze based on the
chemical analysis. But even then, there are other factors (I guess, as Tony
Hansen says, the mineralogical and physical characteristics) which often
prevent reproducing the glaze even when the chemical analysis matches.
Personally, I think it is a sort of laziness. If the potter involved has
not tested it with the frit and found it to be basically the same glaze, I
don't think the frit should be recommended. And if they HAVE tested it and
found it to be basically the same glaze, then why mention the GB version at
all? Maybe the note about the frit is added by the editor?
I am NOT discussing the situation where the potter provides a frit
substitute recipe based on the chemical analysis along with the caveat that
the frit version hasn't been tried. We see that frequently on Clayart, but
I haven't seen it in these magazine articles.
Holly
East Bangor, PA
>----- Original Message -----
>From: "Alisa Clausen"
>I am refering to an article in Pottery Making Illustrated, May/June 2003.
>Article by Maria Spies "How to make a rattle mug". Just got my copy.
>........portion of email omitted..............
>I am very curious as to why this can be cited as a substitute for Gerstely
Borate?. Is it because >it gives the flux/melt needed like my Frit, but
after analysis, can it really be used as a suitable >sub.? If so, is this a
new finding?
Ron Roy on tue 3 jun 03
Hi Holly,
It is probably not laziness - probably ignorance.
Up until the last few years not many potters had a clue about subbing in
materials mol for mol. They simply don't know what to do so they bail out.
It must be fairly traumatic for anyone that should know and has to convert
a GB recipe - but can't. Take a look at the books that are still being
published with Gerstley Borate in the glazes.
Again this is a comment on how irresponsible it has been to ignore the
technical aspect of our craft. It is one thing for a potter to say I am not
interested but it is another matter for a teacher to adopt that attitude.
We can also blame ourselves - because we want simple answers - in fact we
were happy to have them that way. Simple recipes, simple clays and glazes,
simple firing, simple books with lots of pictures. We as a community
demanded simplicity so we could just make pots - doing was so much easier
than thinking.
As in most things some sort of balance is the better way.
Things are getting better - fast. That you had enough smarts to post your
question attests to that. The revolution is in full swing and I for one
find it refreshing and exciting but it has taxed my patience.
RR
>I also have noticed recent articles in ceramics magazines quoting recipes
>with Gerstley Borate, and I wonder why they choose to publish them, since it
>is unrealistic for people to spend much time working on developing GB
>glazes. And I have also seen the recipes with an asterisk after the GB,
>with a note to substitute a boron frit.
>
>I think many of us who have worked on converting GB glazes would attest
>that, while the recipe with a boron frit may make a glaze, may even make a
>NICE glaze, it is very common that it will NOT make the glaze discussed in
>the article. Especially without altering the rest of the glaze based on the
>chemical analysis. But even then, there are other factors (I guess, as Tony
>Hansen says, the mineralogical and physical characteristics) which often
>prevent reproducing the glaze even when the chemical analysis matches.
>
>Personally, I think it is a sort of laziness. If the potter involved has
>not tested it with the frit and found it to be basically the same glaze, I
>don't think the frit should be recommended. And if they HAVE tested it and
>found it to be basically the same glaze, then why mention the GB version at
>all? Maybe the note about the frit is added by the editor?
>
>I am NOT discussing the situation where the potter provides a frit
>substitute recipe based on the chemical analysis along with the caveat that
>the frit version hasn't been tried. We see that frequently on Clayart, but
>I haven't seen it in these magazine articles.
>
>Holly
>East Bangor, PA
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Alisa Clausen on tue 3 jun 03
Dear Tom, Snail and Lily,
Thanks for the answers to my post. I work more or less like Snail, in that
the Frit sub. gives a similar result, so I use it. After I read this
article, I thought maybe
that 3134 had been "established" as a sub. I can see it used the same way
I use Frit as a sub. I have one now without the small amount of Barium that
the other Frit had.
A good enough result if we are not analysing the glaze.
OK.
Thanks and regards, Alisa in Denmark
iandol on tue 3 jun 03
Dear Alisa Clausen,=20
I whole heartedly support your notion of replacing Gerstly Borate with =
Frit 3134, or any other frit which blends in to a recipe by virtue of =
its oxide distribution.
I have done it with one of my own glazes recently and can confirm that =
the finish of the glazes so treated is as near to identical to the =
original that differences are not noticeable.
Why should it work? Most borate materials have relatively low melting =
points (In contrast to Borides which are highly refractory even though =
they show strong fluxing behaviour, no, not flux in the ceramic sense =
but in the sense of scouring an oxide surface!!). As the kiln heats up, =
both the Borates and Boron Rich Frits are among the first materials to =
melt. Once they become fluid they act as strong solvents for all of the =
other ingredients. And this effect becomes stronger as temperature =
rises. Twenty four percent means a high volume of fluid in a mixture =
above 1000 deg Celsius.=20
I think it is pertinent to ask questions about the change in viscosity =
caused by doing this sort of thing. Does it make the glaze melt more =
fluid or more viscous. Such information is of good practical value yet =
rarely mentioned.
Best regards,
Ivor Lewis. Redhill, South Australia
Ababi on wed 4 jun 03
Without reading all the letters I think I know where this mistake comes from: A raku
recipe calls for G.B. and says you may replace it with 3134. It might work for that raku
recipe but raku glaze is not expected to be more than a "bad uneven" glaze.
Ababi
(Spent a year finding the best uneven glaze!)
Lily Krakowski on wed 4 jun 03
Ron Roy writes:
> Hi Holly,
>
> It is probably not laziness - probably ignorance.
>
> Up until the last few years not many potters had a clue about subbing in
> materials mol for mol. They simply don't know what to do so they bail out.
>
> It must be fairly traumatic for anyone that should know and has to convert
> a GB recipe - but can't. Take a look at the books that are still being
> published with Gerstley Borate in the glazes.
>
> Again this is a comment on how irresponsible it has been to ignore the
technical aspect of our craft.
Ron's words as usual are as sober and well-chosen as they are wise.
I make no bones about the fact that I was taught glaze technology from my
first day at SAC. And when I teach--and have only taught recreational
classes--I harrass my students and teach something ABOUT glaze technology.
Unlike the generous Ron I find NO excuse for NOT learning the basics of our
craft.
(PRUDES: HIT DELETE KEY HERE!!!!!!)There is a great line in "Who's Afraid
of Virginia Woolf" in which the "heroine" tells a young man who has,
harrumph, proved a failure in the night, "You'rE either a stud or a bus
boy" Not sure the quote is exact, but the idea is correct.
( PRUDES; YOU MAY RETURN TO THE ROOM) Either you are going to be a potter,
or you are going to be an schlump-- DECIDE. Don't spend another penny on
anything clay related if you plan to be a schlump.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
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