Wade Blocker on thu 30 aug 01
This excellent red gold glaze cone 4-6, was submitted by Milt Friedly CM
November 1991. Mia in ABQ
Marianne Lombardo on thu 30 aug 01
I had several requests for this glaze, so I decided I may as well post =
it. I am not sure who originally wrote this glaze.
Please note that it is probably NOT food safe. I would advise =
decorative use only.
DECORATIVE USE ONLY!!!
Red Gold Gloss ^6 Oxidation
---------------------------------------
2.0 Barium carb
7.0 Gerstley Borate
11.0 Lithium carb
3.0 Magnesium carbonate
14.0 Whiting
24.0 Neph Sy
39.0 Flint
6.0 Zircopax
17.0 Red Iron Oxide
6.0 Rutile
Veena Raghavan on thu 30 aug 01
Message text written by Ceramic Arts Discussion List
><
This glaze was tested by Alisa Clausen and posted on the list. She had
written that it came from C.M. Nov. 91.
Veena Raghavan
75124.2520@compuserve.com
Paul Lewing on thu 30 aug 01
on 8/30/01 8:23 PM, Marianne Lombardo at mlombardo@NEXICOM.NET wrote:
> Please note that it is probably NOT food safe. I would advise =
> decorative use only.
Hi, Marianne.
I would also conclude that this glaze would not be stable, but I was
wondering what led you to that conclusion.
If your conclusion was based on the fact that there's only .13 moles of
Al2O3 and 1.97 of SiO2, I'm with you all the way. But if you think this is
definitely not food-safe because of the 2% barium carbonate (.02 moles), I'd
have to say you're being alarmist. If it's the 11% lithium carbonate (.33
moles), this is a subject that's been debated at GREAT length in this forum,
and I don't think there's a definitive answer as to whether that much LiO in
an unstable glaze would be harmful.
Just making sure we're not reaching the right conclusion from the wrong
facts here.
Paul Lewing, Seattle
tomsawyer on thu 30 aug 01
This is a great glaze in oxidation or reduction at ^6. I like it both ways
but probably favor reduction.
Tom Sawyer
tsawyer@cfl.rr.com
Paul Lewing on fri 31 aug 01
on 8/31/01 3:36 PM, Marianne Lombardo at mlombardo@NEXICOM.NET wrote:
> I want to buy a glaze calc program, so I have downloaded trial versions of
> both Insight and Glazechem. I entered the recipe in both and realized
> theAI203 and Si02 were both very low, so I think the glaze surface may not
> be hard enough to be food safe.
>
> Problem is, for beginners, neither glaze program has utilities to suggest
> what to add to compensate to try and readjust a recipe. I can try
> increasing the Flint, but not sure what else would provide enough AI203.
Adding silica will indeed increase the SiO2, but you're right, it would not
add any Al2O3. A better bet would be to add a clay, which would provide
both. Kaolin would work and so would ball clay, although the fired result
might be different. Most clays have a ratio of Al to Si of about 6:1. If
I remember right, this glaze has a ratio of about 8.5, which means that, to
keep the Si:Al ratio the same, you'd want to add enough clay to get the Al
up where you want it, then add a bit more silica to get the Si up where you
need it. You want to maintain the same Si:Al ratio, because that will
determine the matteness or glossiness of the glaze to a large extent.
Adding both Al and Si will not only decrease the possibility of leeching,
they will also make the surface harder.
I'm not familiar with GlazeChem, and probably have a different version of
Insight than you do, since I have a Mac. But most glaze calculation
programs have a set of what are called limit formulas somewhere. They're
what we've all been using to know that the Al and the Si are too low in this
case. And many of them also have some kind of suggestions as to where you
can get more Al or Si or whatever it is you need.
Good luck, Paul Lewing
Marianne Lombardo on fri 31 aug 01
Other than photos, I have never, ever seen a pot done in reduction. Do you
have both a gas and an electric kiln?
Marianne Lombardo
Omemee, Ontario, Canada
email: mlombardo@nexicom.net
----- Original Message -----
From: "tomsawyer"
To:
Sent: Thursday, August 30, 2001 11:49 PM
Subject: Re: Red gold glaze recipe
> This is a great glaze in oxidation or reduction at ^6. I like it both ways
> but probably favor reduction.
> Tom Sawyer
> tsawyer@cfl.rr.com
>
>
____________________________________________________________________________
__
> 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.
>
Alisa og Claus Clausen on fri 31 aug 01
Thanks Veena,
I just replaced my response with this to you instead.
But if anyone has that issue, which I do not, perhaps they can give the
recipe it's true credit.
I just tried it under Chris Wolff's Cream. Wowy stuff. It gives a very
custard like cream with streaking of
opalescent blues all over. It was very, very streaky, but not runny. I
would still not overlap all the way to the
foot. Very strong colors, smooth and glossy.
Best regards,
Alisa in Denmark.
Marianne Lombardo on fri 31 aug 01
Hi Paul
I want to buy a glaze calc program, so I have downloaded trial versions of
both Insight and Glazechem. I entered the recipe in both and realized
theAI203 and Si02 were both very low, so I think the glaze surface may not
be hard enough to be food safe.
Problem is, for beginners, neither glaze program has utilities to suggest
what to add to compensate to try and readjust a recipe. I can try
increasing the Flint, but not sure what else would provide enough AI203.
Marianne
----- Original Message -----
From: "Paul Lewing"
To:
Sent: Thursday, August 30, 2001 1:14 PM
Subject: Re: Red gold glaze recipe
> on 8/30/01 8:23 PM, Marianne Lombardo at mlombardo@NEXICOM.NET wrote:
>
> > Please note that it is probably NOT food safe. I would advise =
> > decorative use only.
>
> Hi, Marianne.
> I would also conclude that this glaze would not be stable, but I was
> wondering what led you to that conclusion.
> If your conclusion was based on the fact that there's only .13 moles of
> Al2O3 and 1.97 of SiO2, I'm with you all the way. But if you think this
is
> definitely not food-safe because of the 2% barium carbonate (.02 moles),
I'd
> have to say you're being alarmist. If it's the 11% lithium carbonate (33
> moles), this is a subject that's been debated at GREAT length in this
forum,
> and I don't think there's a definitive answer as to whether that much LiO
in
> an unstable glaze would be harmful.
> Just making sure we're not reaching the right conclusion from the wrong
> facts here.
> 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 Hesselberth on sat 1 sep 01
on 8/31/01 11:36 AM, Marianne Lombardo at mlombardo@NEXICOM.NET wrote:
> Problem is, for beginners, neither glaze program has utilities to suggest
> what to add to compensate to try and readjust a recipe. I can try
> increasing the Flint, but not sure what else would provide enough AI203.
Hi Marianne,
When both alumina and silica are low, the simplest thing to do is add clay
until you get the alumina where you want it. Then add silica to bring it up.
That said, though, this particular glaze may not be worth trying to make
more stable. It has 11% lithium carbonate which, because it is relatively
soluble, can give very unpredictable results. If you really wanted to try
to turn this glaze into a reliable, stable glaze you should source the
lithium from spodumene, get rid of the barium (at this low a level you could
probably substitute 1.5% strontium carbonate and not notice the difference)
and get enough alumina and silica. By the time you did all that you very
likely would have a different looking glaze. You would also need to worry
about whether or not it is overloaded with red iron oxide. I have seen some
glazes do poorly in a dishwasher when they get this much iron in them.
Learning to use glaze calculation software to improve glazes takes some
time, but keep at it. You really will begin to get the hang of it pretty
quickly.
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.
Lawrence Ewing on sat 1 sep 01
Hi Marianne,
perhaps you would like to try Matrix. You can download a demo version from
http://www.Matrix2000.co.nz
Matrix also has an instructional program on its web site called GlazeTeach
and Tutorials which may help you in deciding how to adjust recipes.
Cheers,
Lawrence Ewing
Senior Lecturer
Ceramics Department
School of Art
Otago Polytechnic
Dunedin
New Zealand
email: lewing@clear.net.nz
phone +64 03 472 8801
MATRIX GLAZE CALCULATION SOFTWARE:
http://www.Matrix2000.co.nz
GLAZETEACH:
http://www.Matrix2000.co.nz/GlazeTeach
MATRIX TUTORIALS:
http://www.Matrix2000.co.nz/MatrixTutorials
MATRIX ADDITIONAL MATERIALS RESOURCE:
http://www.Matrix2000.co.nz/MatrialsWeb/default.htm
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Marianne Lombardo
Sent: Saturday, September 01, 2001 3:36 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Red gold glaze recipe
Hi Paul
I want to buy a glaze calc program, so I have downloaded trial versions of
both Insight and Glazechem. I entered the recipe in both and realized
theAI203 and Si02 were both very low, so I think the glaze surface may not
be hard enough to be food safe.
Problem is, for beginners, neither glaze program has utilities to suggest
what to add to compensate to try and readjust a recipe. I can try
increasing the Flint, but not sure what else would provide enough AI203.
Marianne
----- Original Message -----
From: "Paul Lewing"
To:
Sent: Thursday, August 30, 2001 1:14 PM
Subject: Re: Red gold glaze recipe
> on 8/30/01 8:23 PM, Marianne Lombardo at mlombardo@NEXICOM.NET wrote:
>
> > Please note that it is probably NOT food safe. I would advise =
> > decorative use only.
>
> Hi, Marianne.
> I would also conclude that this glaze would not be stable, but I was
> wondering what led you to that conclusion.
> If your conclusion was based on the fact that there's only .13 moles of
> Al2O3 and 1.97 of SiO2, I'm with you all the way. But if you think this
is
> definitely not food-safe because of the 2% barium carbonate (.02 moles),
I'd
> have to say you're being alarmist. If it's the 11% lithium carbonate (33
> moles), this is a subject that's been debated at GREAT length in this
forum,
> and I don't think there's a definitive answer as to whether that much LiO
in
> an unstable glaze would be harmful.
> Just making sure we're not reaching the right conclusion from the wrong
> facts here.
> 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.
>
____________________________________________________________________________
__
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.
Joan Ashworth on sun 2 sep 01
I have tested this using South African ingredients, for any South Africans
out there who wish to try.
It is indeed a lovely glaze, semi gloss (our kaolins seem to have a little
more silica than the American ones), and a mottled and furred red brown. No
gold.
Joan
in Durban
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