John Hesselberth on sun 22 jul 01
on 7/22/01 12:36 AM, Tom Buck at Tom.Buck@HWCN.ORG wrote:
> There are available at least four substitutes for Gerstley Borate
> and they include:
> Murray's Borate, a frit containing Calcium boro-silicate and
> Sodium boro-silicate and small amounts of magnesium (as silicate) and
> alumina (Mary Simmons reported the anlysis on Clayart last year); MB
> mixes tend to settle in a few hours.
> Boraq, a material mix that emulates GB, it contains ulexite and
> colemanite as did GB. Prepared by Plainsman Clays, it provides a
> suspension activity similar to GB.
> Gillespie borate, from Hammill & Gillespie, is a material mix that
> like Boraq uses ulexite and colemanite, and behaves much like GB in its
> good years.
> Laguna borate, also a material mix that relies on Cadycal (a
> chemically-produced Calcium borate). Glaze mixes with it tend to settle in
> a few hours.
There was apparently not enough demand for GB to keep the mine open. Now we
have at least 4 "substitutes" being offered for sale. How many of the above
substitutes are likely to be economically successful for their producers?
1? 2 at most? I'm willing to bet some of these will not be available for
very long. Which ones? Of course, the one(s) that go out of business WILL
be the ones I would have chosen to reformulate my glazes with and then I
would be right back in trouble looking for another substitute. That's why
I'm going to get my boron from frits that have been available for a long
time and have proven consistency.
Regards, John
Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.com
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
will edwards on sun 22 jul 01
Hi,
I have found something this time with John H. I can fully agree on heavil=
y.
John has made great sense with his observations and I think under the
circumstances that it would be wise to consider what he is saying. The
experience I have in business tells me to be aware of such changes and ta=
ke
them for less than face value. Mr. Hessleberth thanks for defining this!=
William Edwards
'
There was apparently not enough demand for GB to keep the mine open. Now =
we
have at least 4 "substitutes" being offered for sale. How many of the abo=
ve
substitutes are likely to be economically successful for their producers?=
1? 2 at most? I'm willing to bet some of these will not be available for
very long. Which ones? Of course, the one(s) that go out of business WILL=
be the ones I would have chosen to reformulate my glazes with and then I
would be right back in trouble looking for another substitute. That's why=
I'm going to get my boron from frits that have been available for a long
time and have proven consistency.
james w. thomas on mon 23 jul 01
I don't know the glaze your using but there may be something that everyone dealing with frit should know about the very nature of the beast.
From what I understand, Frit is by nature a glass. I have taken a few glass fusion classes and there I found that glass is heated to anywhere from say 1620 degrees F (for plate glass) until it reaches a liquid state. The syrupy goo glowing bright red is stirred and mixed thoroughly then poured into a cullet shape( simply a term for a hunk of glass most often round). This then can be dropped into cold running water which shatters the glass. The glass is now pea gravel size this can be ground into fine grade of powder commoly known as Frit.
If one looks at ceramic frit as being in the same ball park a plate glass or bottle glass it's easy to see why frit will not stay suspended in a glaze very well. The water in a glaze acts as a lubricant since it cannot be absrobed into the glass and the stuff just follows gravity.
Last year I did several experiments on glass casting. I used ferro 3110 to cast a small shape and it worked very well. I had an opague bluish white GLASS sculpture that showed a sparkly translucent light thru it.
Also there is a form of art glass called Pate de Verre (I think that's French for paste of glass). With Pate de Verre glass frit of very fine gauge is mixed with gum arabic and water. This, while very thick, is packed into a ceramic mold that has been coated in glass shelf primer (kiln wash often with a color added) This is fired to circa 1500 F to give a finished 3-D relief, bowl or sculptural shape that has inner an inner glow. The glow is from tiny air bubbles that are trapped in the glass.
Glass Fusing Book One by Boyce Lundstrum
Advanced Fusing Techniques Glass Fusing Book Two by Boyce Lundstrum
Glass Casting and Mold Making by Boyce Lundstrum
Pate de Verre and Kiln Casting of Glass by Jim Kervin and Dan Fenton
To make a long story short from my experiences with glass fusion and raku firing I find that I get less bubbles and a smoother gloss if I use a short soak time at the proper temp. Also if both sides of the piece in and out have a thick gloss glaze I have to watch and wait for gasses to vent form the clay body.
The bright sparkly effect of frit glazes are evidently microscopic air bubbles and fractures in the glass I mean glaze as in primary and secondary cracks in clear-crackle Raku.
Now I don't know if all ceramic frits are made this way but I do believe that they are some form of a glass when one looks at the chemical analysis.
I hope this helps in some way.
>From: John Forstall
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: Gerstley Borate substitutes--food for thought
>Date: Mon, 23 Jul 2001 19:54:45 -0500
>
>John Hesselberth, or Anyone,
>
>I also would like to get boron from frits, but nearly every clear recipe I
>try to
>sub GB with 3134 comes out with millions of trapped bubbles. I fire bisque
>to large cone 04.
>
>One of the worse is Tony's 5 x 20. Do I have a bad batch of 3134? Could
>one of the other ingredients in this glaze be causing this?
>
>Thanks,
>John
>(John Forstall, Pensacola, FL.)
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
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John Forstall on mon 23 jul 01
John Hesselberth, or Anyone,
I also would like to get boron from frits, but nearly every clear recipe I
try to
sub GB with 3134 comes out with millions of trapped bubbles. I fire bisque
to large cone 04.
One of the worse is Tony's 5 x 20. Do I have a bad batch of 3134? Could
one of the other ingredients in this glaze be causing this?
Thanks,
John
(John Forstall, Pensacola, FL.)
John Hesselberth on tue 24 jul 01
on 7/23/01 8:54 PM, John Forstall at johnfors@WORLDNET.ATT.NET wrote:
> I also would like to get boron from frits, but nearly every clear recipe I
> try to
> sub GB with 3134 comes out with millions of trapped bubbles. I fire bisque
> to large cone 04.
>
> One of the worse is Tony's 5 x 20. Do I have a bad batch of 3134? Could
> one of the other ingredients in this glaze be causing this?
Hi John,
The first thing to try is a 20 minute soak at peak temperature. I can see
some tiny bubbles in almost every transparent glaze, but nothing that
seriously affects anything.
Regards,
John
Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.com
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
Paul Lewing on tue 24 jul 01
Speaking of GB substitutes, I just noticed a reference in a new book to a
boron frit I'd never heard of. This is in Michael Bailey's terrific new
book, "Glazes, Cone 6, 1240 C", published by A&C Black in London and U of
Penn. Press in the US. Lots of great information and recipes and nice
photos- even one of my pieces, just to bring down the curve.
Anyway, several of the recipes call for "low-expansion frit". In the
Appendices, there are analyses listed for several of these, including the
one I was most interested in, Ferro 3249. I haven't checked with my local
supplier to see if they carry this stuff, but they sound great. What really
attracted me to it was the fact that it had 1.137 moles of B2O3, much
higher than 3134 (.633) or 3124 (.519), and the main flux in it was MgO.
The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
1.919. I don't know what the expansion on this would be without running it
through a calculation program, but it must be seriously low.
Anybody ever tried this stuff?
There are also four other low-expansion frits listed, which are similar.
Paul Lewing, Seattle
David Hewitt on wed 25 jul 01
I agree that this is a most interesting book and could be of particular
interest to cone 6 potters wanting to avoid GB. None of the testing work
reported involved GB, as this is not commonly used this side of the
Atlantic. Also much of the book relates to cone 6 glazes, that do not
require any B2O3, and how these have been developed.
David
In message , Paul Lewing writes
>Speaking of GB substitutes, I just noticed a reference in a new book to =
>a
>boron frit I'd never heard of. This is in Michael Bailey's terrific new
>book, "Glazes, Cone 6, 1240 C", published by A&C Black in London and U of
>Penn. Press in the US. Lots of great information and recipes and nice
>photos- even one of my pieces, just to bring down the curve.
>Anyway, several of the recipes call for "low-expansion frit". In the
>Appendices, there are analyses listed for several of these, including the
>one I was most interested in, Ferro 3249. I haven't checked with my loca=
>l
>supplier to see if they carry this stuff, but they sound great. What rea=
>lly
>attracted me to it was the fact that it had 1.137 moles of B2O3, much
>higher than 3134 (.633) or 3124 (.519), and the main flux in it was MgO.
>The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
>1.919. I don't know what the expansion on this would be without running =
>it
>through a calculation program, but it must be seriously low.
>Anybody ever tried this stuff?
>There are also four other low-expansion frits listed, which are similar.
>Paul Lewing, Seattle
--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Web site http://www.dhpot.demon.co.uk
Ababi on wed 25 jul 01
Hello Paul
Ferro Europe make different( as well as the regular) frits and glazes.
Different from the general way of the regular American frits. Their
facilities are in Portugal, as far as I know and I am waiting for the
book which I have ordered from Steve Mills the partner of Mike Bailey,
You make the next days long-waiting for the book ! I am not surprise
that they have more frits that are not available over there:(You read:
Over here)
Yesterday, while I deleted many frits from the Glaze Simulator I saw
many interesting frits of Fusion, too (you side of the sea).
Ababi
---------- Original Message ----------
>Speaking of GB substitutes, I just noticed a reference in a new book
>to a
>boron frit I'd never heard of. This is in Michael Bailey's terrific new
>book, "Glazes, Cone 6, 1240 C", published by A&C Black in London and U
>of
>Penn. Press in the US. Lots of great information and recipes and nice
>photos- even one of my pieces, just to bring down the curve.
>Anyway, several of the recipes call for "low-expansion frit". In the
>Appendices, there are analyses listed for several of these, including
>the
>one I was most interested in, Ferro 3249. I haven't checked with my
>local
>supplier to see if they carry this stuff, but they sound great. What
>really
>attracted me to it was the fact that it had 1.137 moles of B2O3, much
>higher than 3134 (.633) or 3124 (.519), and the main flux in it was MgO.
>The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
>1.919. I don't know what the expansion on this would be without
>running it
>through a calculation program, but it must be seriously low.
>Anybody ever tried this stuff?
>There are also four other low-expansion frits listed, which are similar.
>Paul Lewing, Seattle
>________________________________________________________________________
>______
>Send postings to clayart@lsv.ceramics.org
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
John Forstall on wed 25 jul 01
Thanks to John H. who started the thread, and all who responded. Some of
you suggested gas trapped in bisque fired too fast through low temp phase.
Here is temp rise for both bisque and glaze in my kiln. For Glaze firing I
soak at ^6 for one hour.
1st hour rise=250 deg.F.
2nd =465
3rd =435
4th =535
Total rise in 4 hours=1700 deg.F.
Is this too fast? Could this cause trapped bubbles when using 3134 even
though no bubbles with GB in same firing? Thanks for help folks.
John
(John Forstall, Pensacola, FL.)
on 7/23/01 8:54 PM, John Forstall at johnfors@WORLDNET.ATT.NET wrote:
> I also would like to get boron from frits, but nearly every clear recipe I
> try to
> sub GB with 3134 comes out with millions of trapped bubbles. I fire
bisque
> to large cone 04.
>
> One of the worse is Tony's 5 x 20. Do I have a bad batch of 3134? Could
> one of the other ingredients in this glaze be causing this?
Snail Scott on wed 25 jul 01
At 11:35 AM 7/25/01 -0500, you wrote:
>...Total rise in 4 hours=1700 deg.F.
>>Is this too fast? Could this cause trapped bubbles when using 3134 even
>though no bubbles with GB in same firing?...
>(John Forstall, Pensacola, FL.)
This is pretty fast. I get this problem even with
slow-bisqued, multiple-fired work, though, so I
don't think speed of bisque is the core of the
problem.
You can get bubbles in frit glazes even when other
glazes don't have them. It's my understanding that
many frits tend to form a high-viscosity layer
which can 'seal in' the bubbles that would normally
escape from a GB-fluxed or other glaze. (I forget
where I heard that first, but it seems consistent
with my observations.) It seems especially bad with
frit-fluxed matt glazes. (More viscosity problems,
I figure.) The surface smoothness of the clay seems
to play a role also - I always get more bubbles in
areas that are scraped, not smoothed.
-Snail
Richard G. Ramirez on wed 25 jul 01
That Elecric^6 or Gas^6(Reduction)?...TIA...
----- Original Message -----
From: "David Hewitt"
To:
Sent: Tuesday, July 24, 2001 11:44 PM
Subject: Re: Gerstley Borate substitutes--food for thought
> I agree that this is a most interesting book and could be of particular
> interest to cone 6 potters wanting to avoid GB. None of the testing work
> reported involved GB, as this is not commonly used this side of the
> Atlantic. Also much of the book relates to cone 6 glazes, that do not
> require any B2O3, and how these have been developed.
> David
>
> In message , Paul Lewing writes
> >Speaking of GB substitutes, I just noticed a reference in a new book to
=
> >a
> >boron frit I'd never heard of. This is in Michael Bailey's terrific new
> >book, "Glazes, Cone 6, 1240 C", published by A&C Black in London and U of
> >Penn. Press in the US. Lots of great information and recipes and nice
> >photos- even one of my pieces, just to bring down the curve.
> >Anyway, several of the recipes call for "low-expansion frit". In the
> >Appendices, there are analyses listed for several of these, including the
> >one I was most interested in, Ferro 3249. I haven't checked with my
loca=
> >l
> >supplier to see if they carry this stuff, but they sound great. What
rea=
> >lly
> >attracted me to it was the fact that it had 1.137 moles of B2O3, much
> >higher than 3134 (.633) or 3124 (.519), and the main flux in it was MgO.
> >The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
> >1.919. I don't know what the expansion on this would be without running
=
> >it
> >through a calculation program, but it must be seriously low.
> >Anybody ever tried this stuff?
> >There are also four other low-expansion frits listed, which are similar.
> >Paul Lewing, Seattle
>
> --
> David Hewitt
> David Hewitt Pottery ,
> 7 Fairfield Road, Caerleon, Newport,
> South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
> FAX:- +44 (0) 870 1617274
> Web site http://www.dhpot.demon.co.uk
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Patricia & John Richmond on thu 26 jul 01
Have you tried re-firing your pieces to see if the bubbles smooth out. I have several clay bodies that cause bubbling on the first firing and smooth out on the second. The fault is the clay and not the glazes.
--
Patricia & John Richmond
jrichmond4@cfl.rr.com
Port Orange, Florida 32129
Paul Lewing on thu 26 jul 01
on 7/27/01 3:47 AM, Ron Roy at ronroy@TOTAL.NET wrote:
> There is a big exception to this - iron becomes a strong flux in reduction.
> The more iron the more running - not so important for a tile maker it's
> true - but for the rest of us - protect your shelves!
>
> RR
>
>
>> a glaze that
>> "works" in oxidation will also "work" at that same temperature in reduction.
Ron is, of course, right again. I had forgotten that one exception, and
made a generalization. And as Oliver Wendell Holmes said, "All
generalizations are false, including this one".
Paul Lewing, Seattle
Paul Lewing on thu 26 jul 01
on 7/27/01 3:27 AM, Ron Roy at ronroy@TOTAL.NET wrote:
> Be careful now - MgO has a very low expansion rate - 10 times lower than
> sodium and potassium and 4 times lower than calcium. That makes this frit
> have a very low expansion rate - better to calculate than start wholesale
> substitution of one frit for another.
>
>> The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
>> 1.919. I don't know what the expansion on this would be without running it
>> through a calculation program, but it must be seriously low.
Very true, Ron. I probably should have started another thread to ask this
question rather than adding it into the ongoing one about GB substitutions,
because I never meant to imply it was a substitute. This stuff would
obviously be very different from GB, or any frit I'm familiar with, either.
That's why I found it so intriguing.
Paul Lewing
Paul Lewing on thu 26 jul 01
on 7/25/01 7:56 PM, Richard G. Ramirez at r12396@HOME.COM wrote:
> That Elecric^6 or Gas^6(Reduction)?
I believe Mr. Bailey says that he's dealing mostly with oxidation, but I
think there's some in there about reduction, too. And anyway, it hardly
matters. It's the chemistry information that's important, and a glaze that
"works" in oxidation will also "work" at that same temperature in reduction.
It will probably just look different. It's up to you to decide whether
that's "wrong" or "right".
Paul Lewing, Seattle
Ron Roy on thu 26 jul 01
Be careful now - MgO has a very low expansion rate - 10 times lower than
sodium and potassium and 4 times lower than calcium. That makes this frit
have a very low expansion rate - better to calculate than start wholesale
substitution of one frit for another.
MgO has a strong effect on colour - read about it in Hamer's book before
you go off the deep end.
RR
>The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
>1.919. I don't know what the expansion on this would be without running it
>through a calculation program, but it must be seriously low.
>Anybody ever tried this stuff?
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
Ron Roy on thu 26 jul 01
There is a big exception to this - iron becomes a strong flux in reduction.
The more iron the more running - not so important for a tile maker it's
true - but for the rest of us - protect your shelves!
RR
> a glaze that
>"works" in oxidation will also "work" at that same temperature in reduction.
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
Ababi on fri 27 jul 01
I wonder, if during substituting G.B. for raku, through a software, we
have to include the MgO, as it is a midi high fire flux, it might be
bad for melting the glaze. I know Tom Buck includes it in his Raku
recipes. I would like to know more, because, when we use software,
perhaps we don't have to imitate the material TOTALLY, in a case like
this. Means: If the MgO is bad,for^08 maturing I will have a bit
different analysis, but a better glaze.
Just to tell you, after a few months of tests, including buying all
kind of weird frits, I purchased 10 Kg, of G.B. Now I can work in
raku, and test more quietly not just testing, like I did before!
Ababi Sharon
Kibbutz Shoval- Israel
officially Glaze addict
ababisha@shoval.ardom.co.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
http://www.israelceramics.org/
---------- Original Message ----------
>Be careful now - MgO has a very low expansion rate - 10 times lower than
>sodium and potassium and 4 times lower than calcium. That makes this
>frit
>have a very low expansion rate - better to calculate than start
>wholesale
>substitution of one frit for another.
>MgO has a strong effect on colour - read about it in Hamer's book before
>you go off the deep end.
>RR
>>The whole analysis is CaO .171, MgO .829, Al2O3 .357, B2O3 1.137, SiO2
>>1.919. I don't know what the expansion on this would be without
>running it
>>through a calculation program, but it must be seriously low.
>>Anybody ever tried this stuff?
>Ron Roy
>RR# 4
>15084 Little Lake Rd..
>Brighton,
>Ontario, Canada
>KOK 1H0
>Residence 613-475-9544
>Studio 613-475-3715
>Fax 613-475-3513
>________________________________________________________________________
>______
>Send postings to clayart@lsv.ceramics.org
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
| |
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