kuthu@BELLSOUTH.NET on fri 12 oct 01
To all those who would put off, or avoid completely, learning
glaze chemistry, I *highly* advise against it. Admittedly, I'm
a geologist, so some of this is a bit easier for me to do than
for others, but I learned alongside my wife who grasped it as
I did- so you don't have to be a geologist or chemist, just
committed. Really, once you do it and figure it out, it's not
that difficult.
The number of glazes I've mixed since I've started in pottery I can
actually count on my hand. Randy's Red, a clear that was given to me,
and a couple I got from Glaze Base. That's it, and I was moderately
successful. If a glaze didn't work, I gave up. I didn't even know why
it went wrong or how to fix it. Now, still as a beginner to the
pottery thing, I'm developing my own glazes, based on what ingredients
I have on hand and what effects/colors I desire.
I know the gurus say this alot, and I don't mean to preach to the
choir, but this is coming from a newbie to other newbies. I know
you're scared, but this is no joke people! Listen, I decided I wanted
a satin-type deep black that would work well with my ^6 Stoneware and
that would break deep blue. After 2 testfires I have one slight
adjustment to alumina and I'm sure it'll be done (Haven't perfected
the blue breaking, but I'll get there too). No wasting time and
chemicals on unknown recipes. No wasting chemicals at all actually,
because if you test small pieces (Or small bowls, as I do- more
throwing practice), then you don't loose enough glaze in a single test
to matter. You can add percentages of chemicals to your test batch in
measured amounts to fix problems. Mine needs a bit more alumina, so I
add some more to my batch and I have not wasted anything, at the end,
all the glaze is good glaze.
Look, seriously, I took it upon myself to learn this relatively soon
after starting pottery. From the posts on the list, I can tell that
many don't- some may never learn it. I'm sure that there are
production potters who could put anything I produce to shame who have
never learned this, and if that works for them, fine. If you are like
me, however, and want to understand and have control over your clay
and glazes, and be able to anticipate, predict and determine the
outcome of your work- you owe it to yourself to take a day, or a
weekend, and learn this. I predict you'll never go back.
The two books I read to learn this are "Glazes: Cone 6" by Michael
Bailey and the seminal "Clay and Glazes for the Potter" By the late
Daniel Rhodes. Outstanding books both, with many examples.
I'm not using recipes anymore. Ever. It's not worth it- different
kiln, different methods, different attitudes when mixing. When I see a
recipe I like now, I *immediately* change it into a unity oxide
representation to see what it's really saying. I can plot it to
estimate the outcome, think about the actual amounts of oxides and
what the consequences of them are, etc. Then I reformulate it to a
batch recipe using my chosen raw ingredients. Often they are the same-
at least I know what to change when something goes wrong! Sometimes
they are different- invariably the glaze works. It might not look
exactly how it did in the original recipe- hell, just my kiln
environment can change that. Changing the raw ingredients *will*
change the glaze, let's not kid ourselves- chemistry's not that
simple. But the point is that I *always* end up with a glaze that
works, because I know what I started with, know the consequences, and
can adapt the formula.
No, I don't have a computer program. I'm a UNIX user, and have to
write one myself. I'll eventually write the free one I mentioned
before, but not until I need it myself- and I've gotten so used to
doing this on paper relatively quickly that I won't need it anytime
soon.
Do it. Stop wasting time, energy and chemicals. Do it so that I can
shut up and stop sounding like a salesman :-)
-Jonathan
(Why aren't *all* geologists avid potters?)
Jeremy/Bonnie Hellman on fri 12 oct 01
And for those who are now ready to take this message to heart, we have a
great learning opportunity! Our own Paul Lewing (who is scheduled to be one
of the Glaze Doctors at the 2002 NCECA) is presenting a weekend workshop at
the Creative Oasis in State College, PA, on October 20th & 21st.
I know of 4 clayarters who are attending, and it would be great to have more
of us.
Bonnie
In a previous posting, Charles wrote:
> This workshop will be held at
> R&T's Creative Oasis
> 133 E. Beaver Avenue
> State College, PA
> on Oct 20 and 21
>
> REGISTRATION DEADLINE IS OCTOBER 4
> THERE ARE STILL A FEW SPACES OPEN
>
> (814) 237-1982
> To register online or get hotel information visit:
>
http://www.thecreativeoasis.com/Fall2001Workshops/VisitingArtists/PaulLew
ing.html
> Paul Lewing
> Two Day Glaze Chemistry Workshop
> Workshop Description: This two-day (approximately 6 hours each day)
> lecture will explore ceramic glazes, their constituent materials and
> oxides, and their behavior during firing. The first day will begin
> with a review of the properties of glaze materials, and move on to a
> discussion of testing and mixing procedures. We will discuss color
> response in glazes, surface characteristics, glaze faults, and the
> effect of reduction/oxidation of glazes. Particular emphasis will be
> put on Cone 10 reduction and Cone 5-6 oxidation, the two most
> prevalent firing temperatures and atmospheres. The second day will
> focus on the Seger method of analyzing glaze formulas by constituent
> oxide. We will begin with a simple description of the mathematical
> procedures, and what the numbers mean. The afternoon will be devoted
> to a demonstration of three different computer glaze calculation
> programs. Programs such as this are an increasingly popular and
> prevalent tool in understanding glaze chemistry. They aid greatly in
> adjusting firing temperature, surface characteristics, and the fit
> of glaze to clay, and provide useful information on opacity and
> color development. Handouts will be provided with Cone 10 and Cone 5
> glaze recipes, and information about glaze materials, oxides, and
> firing. The workshop will conclude with a slide show of Paul's work
> in pottery and tile.
> Resume': Paul Lewing has been working with clay and glazes since
> 1965, and is well known in the Northwest for his unique and
> painterly style of working with ceramic glazes. He is one of a
> growing number of ceramists who have successfully made the switch
> from high-temperature reduction gas firing to mid-range oxidation
> electric firing.
> Date: October 20th & 21st
> Time: 9:00 a.m. - 5:00 p.m.
> Fee: $110.00
> Materials: Notebooks and writing utensils. Laptops are allowed. We
> have several outlets but power is not guaranteed.
> Notes: Participants are encouraged to arrive early to check in.
>
>
> Visit my webpage...
> http://www.thecreativeoasis.com
> From: kuthu@BELLSOUTH.NET
> Reply-To: Ceramic Arts Discussion List
> Date: Fri, 12 Oct 2001 16:37:36 -0000
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Why I learned glaze chemistry (To those who wouldn't)
>
> To all those who would put off, or avoid completely, learning
> glaze chemistry, I *highly* advise against it. Admittedly, I'm
> a geologist, so some of this is a bit easier for me to do than
> for others, but I learned alongside my wife who grasped it as
> I did- so you don't have to be a geologist or chemist, just
> committed. Really, once you do it and figure it out, it's not
> that difficult.
>
> The number of glazes I've mixed since I've started in pottery I can
> actually count on my hand. Randy's Red, a clear that was given to me,
> and a couple I got from Glaze Base. That's it, and I was moderately
> successful. If a glaze didn't work, I gave up. I didn't even know why
> it went wrong or how to fix it. Now, still as a beginner to the
> pottery thing, I'm developing my own glazes, based on what ingredients
> I have on hand and what effects/colors I desire.
>
> I know the gurus say this alot, and I don't mean to preach to the
> choir, but this is coming from a newbie to other newbies. I know
> you're scared, but this is no joke people! Listen, I decided I wanted
> a satin-type deep black that would work well with my ^6 Stoneware and
> that would break deep blue. After 2 testfires I have one slight
> adjustment to alumina and I'm sure it'll be done (Haven't perfected
> the blue breaking, but I'll get there too). No wasting time and
> chemicals on unknown recipes. No wasting chemicals at all actually,
> because if you test small pieces (Or small bowls, as I do- more
> throwing practice), then you don't loose enough glaze in a single test
> to matter. You can add percentages of chemicals to your test batch in
> measured amounts to fix problems. Mine needs a bit more alumina, so I
> add some more to my batch and I have not wasted anything, at the end,
> all the glaze is good glaze.
>
> Look, seriously, I took it upon myself to learn this relatively soon
> after starting pottery. From the posts on the list, I can tell that
> many don't- some may never learn it. I'm sure that there are
> production potters who could put anything I produce to shame who have
> never learned this, and if that works for them, fine. If you are like
> me, however, and want to understand and have control over your clay
> and glazes, and be able to anticipate, predict and determine the
> outcome of your work- you owe it to yourself to take a day, or a
> weekend, and learn this. I predict you'll never go back.
>
> The two books I read to learn this are "Glazes: Cone 6" by Michael
> Bailey and the seminal "Clay and Glazes for the Potter" By the late
> Daniel Rhodes. Outstanding books both, with many examples.
>
> I'm not using recipes anymore. Ever. It's not worth it- different
> kiln, different methods, different attitudes when mixing. When I see a
> recipe I like now, I *immediately* change it into a unity oxide
> representation to see what it's really saying. I can plot it to
> estimate the outcome, think about the actual amounts of oxides and
> what the consequences of them are, etc. Then I reformulate it to a
> batch recipe using my chosen raw ingredients. Often they are the same-
> at least I know what to change when something goes wrong! Sometimes
> they are different- invariably the glaze works. It might not look
> exactly how it did in the original recipe- hell, just my kiln
> environment can change that. Changing the raw ingredients *will*
> change the glaze, let's not kid ourselves- chemistry's not that
> simple. But the point is that I *always* end up with a glaze that
> works, because I know what I started with, know the consequences, and
> can adapt the formula.
>
> No, I don't have a computer program. I'm a UNIX user, and have to
> write one myself. I'll eventually write the free one I mentioned
> before, but not until I need it myself- and I've gotten so used to
> doing this on paper relatively quickly that I won't need it anytime
> soon.
>
> Do it. Stop wasting time, energy and chemicals. Do it so that I can
> shut up and stop sounding like a salesman :-)
>
> -Jonathan
> (Why aren't *all* geologists avid potters?)
>
> ______________________________________________________________________________
> 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.
>
Julie Milazzo on sun 31 mar 02
My favorite uncle is a geologist, and I wanted to be
one REALLY badly... until high school earth science.
We had to identify all these rocks (not just igneous,
sedimentary, etc...), exactly what type of rocks they
were based on the written description the teacher gave
us. I became so frustrated (it doesn't seem to be
enough to write "multisized particles", and expect me
to know that it was granite, and be able to pick it
out of a pile with thirty other types of rocks) that I
stopped going to class. Ah, those were the good old
days, where you could fail all four quarters, but as
long as you passed the regents exam, you'd get
whatever grade you earned on the test. I still can't
identify granite, but I scored a B+ in the class. I
suppose I should thank my shitty teacher, or my shitty
teen attitude, because I may never have discovered
pottery otherwise. I have always loved rocks,
gemstones, dirt, mud, slime, ooze, dirt, grime and all
the other good stuff. Just wish I enjoyed bathing half
as much as getting dirty. Happy potting, and, uh,
rocking! Jules
--- Richard Aerni wrote:
> > ----- Original Message -----
> > From:
> > > Subject: Why I learned glaze chemistry (To those
> who wouldn't)
>
> ...body of message snipped...
>
> > > -Jonathan
> > > (Why aren't *all* geologists avid potters?)
>
> Good question, Jonathan, and one I've wondered about
> as well. And the
> converse...why aren't more potters avid geologists?
> There is so much
> science, and earth science to boot, in potting, that
> they seem to go hand in
> hand, at least to me. But then, I went from geology
> into pottery, with a
> few other stops along the way. Currently, I'm
> trying to bone up on igneous
> petrology, in order to better understand the cooling
> process our silica
> soups go through after having been to cone 10.
>
> Best,
> Richard Aerni
> Bloomfield, NY
>
>
______________________________________________________________________________
> 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.
__________________________________________________
Do You Yahoo!?
Yahoo! Greetings - send holiday greetings for Easter, Passover
http://greetings.yahoo.com/
norman cohen on sun 31 mar 02
kuthu: it's unclear to me ' change to a unity oxide representation'. how
do you make that adjustment, can you detail?
----- Original Message -----
From:
To:
Sent: Friday, October 12, 2001 10:37 AM
Subject: Why I learned glaze chemistry (To those who wouldn't)
> To all those who would put off, or avoid completely, learning
> glaze chemistry, I *highly* advise against it. Admittedly, I'm
> a geologist, so some of this is a bit easier for me to do than
> for others, but I learned alongside my wife who grasped it as
> I did- so you don't have to be a geologist or chemist, just
> committed. Really, once you do it and figure it out, it's not
> that difficult.
>
> The number of glazes I've mixed since I've started in pottery I can
> actually count on my hand. Randy's Red, a clear that was given to me,
> and a couple I got from Glaze Base. That's it, and I was moderately
> successful. If a glaze didn't work, I gave up. I didn't even know why
> it went wrong or how to fix it. Now, still as a beginner to the
> pottery thing, I'm developing my own glazes, based on what ingredients
> I have on hand and what effects/colors I desire.
>
> I know the gurus say this alot, and I don't mean to preach to the
> choir, but this is coming from a newbie to other newbies. I know
> you're scared, but this is no joke people! Listen, I decided I wanted
> a satin-type deep black that would work well with my ^6 Stoneware and
> that would break deep blue. After 2 testfires I have one slight
> adjustment to alumina and I'm sure it'll be done (Haven't perfected
> the blue breaking, but I'll get there too). No wasting time and
> chemicals on unknown recipes. No wasting chemicals at all actually,
> because if you test small pieces (Or small bowls, as I do- more
> throwing practice), then you don't loose enough glaze in a single test
> to matter. You can add percentages of chemicals to your test batch in
> measured amounts to fix problems. Mine needs a bit more alumina, so I
> add some more to my batch and I have not wasted anything, at the end,
> all the glaze is good glaze.
>
> Look, seriously, I took it upon myself to learn this relatively soon
> after starting pottery. From the posts on the list, I can tell that
> many don't- some may never learn it. I'm sure that there are
> production potters who could put anything I produce to shame who have
> never learned this, and if that works for them, fine. If you are like
> me, however, and want to understand and have control over your clay
> and glazes, and be able to anticipate, predict and determine the
> outcome of your work- you owe it to yourself to take a day, or a
> weekend, and learn this. I predict you'll never go back.
>
> The two books I read to learn this are "Glazes: Cone 6" by Michael
> Bailey and the seminal "Clay and Glazes for the Potter" By the late
> Daniel Rhodes. Outstanding books both, with many examples.
>
> I'm not using recipes anymore. Ever. It's not worth it- different
> kiln, different methods, different attitudes when mixing. When I see a
> recipe I like now, I *immediately* change it into a unity oxide
> representation to see what it's really saying. I can plot it to
> estimate the outcome, think about the actual amounts of oxides and
> what the consequences of them are, etc. Then I reformulate it to a
> batch recipe using my chosen raw ingredients. Often they are the same-
> at least I know what to change when something goes wrong! Sometimes
> they are different- invariably the glaze works. It might not look
> exactly how it did in the original recipe- hell, just my kiln
> environment can change that. Changing the raw ingredients *will*
> change the glaze, let's not kid ourselves- chemistry's not that
> simple. But the point is that I *always* end up with a glaze that
> works, because I know what I started with, know the consequences, and
> can adapt the formula.
>
> No, I don't have a computer program. I'm a UNIX user, and have to
> write one myself. I'll eventually write the free one I mentioned
> before, but not until I need it myself- and I've gotten so used to
> doing this on paper relatively quickly that I won't need it anytime
> soon.
>
> Do it. Stop wasting time, energy and chemicals. Do it so that I can
> shut up and stop sounding like a salesman :-)
>
> -Jonathan
> (Why aren't *all* geologists avid potters?)
>
>
____________________________________________________________________________
__
> 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.
Richard Aerni on sun 31 mar 02
> ----- Original Message -----
> From:
> > Subject: Why I learned glaze chemistry (To those who wouldn't)
...body of message snipped...
> > -Jonathan
> > (Why aren't *all* geologists avid potters?)
Good question, Jonathan, and one I've wondered about as well. And the
converse...why aren't more potters avid geologists? There is so much
science, and earth science to boot, in potting, that they seem to go hand in
hand, at least to me. But then, I went from geology into pottery, with a
few other stops along the way. Currently, I'm trying to bone up on igneous
petrology, in order to better understand the cooling process our silica
soups go through after having been to cone 10.
Best,
Richard Aerni
Bloomfield, NY
Roger Korn on mon 1 apr 02
My late mentor, Gary Guy, was fond of saying, "All we do is turn dirt back into
rocks." He referred to glazes as "silica soup."
Roger
Richard Aerni wrote:
> > ----- Original Message -----
> > From:
> > > Subject: Why I learned glaze chemistry (To those who wouldn't)
>
> ...body of message snipped...
>
> > > -Jonathan
> > > (Why aren't *all* geologists avid potters?)
>
> Good question, Jonathan, and one I've wondered about as well. And the
> converse...why aren't more potters avid geologists? There is so much
> science, and earth science to boot, in potting, that they seem to go hand in
> hand, at least to me. But then, I went from geology into pottery, with a
> few other stops along the way. Currently, I'm trying to bone up on igneous
> petrology, in order to better understand the cooling process our silica
> soups go through after having been to cone 10.
>
> Best,
> Richard Aerni
> Bloomfield, NY
>
> ______________________________________________________________________________
> 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.
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
iandol on wed 3 apr 02
Richard Aerni Says, <petrology, in order to better understand the cooling process our silica =
soups go through after having been to cone 10>> in response to Jonathan =
who asked "Why aren't *all* geologists avid potters?"=20
Well, this seems a logical thing to do if the mixtures being energised =
to Cone 10 conform to principles of Igneous Chemistry. But we are not =
dealing with Elemental Magma situations. Many people use lower =
temperatures and do not subject their materials to high pressures. More =
over they may be using blends which might be mutually exclusive in a =
natural setting. Further more, as I understand things, many of the =
ingredients in a Magma which influences the outcome, commonly considered =
to be volatile components, are absent from many glaze recipes. Perhaps a =
study of Metamorphism and its associated chemistries would be more =
appropriate. Certainly the firing of clay is low level metamorphism and =
I suppose the melting of a glaze recipe at atmospheric pressure is as =
well.
Given a set of ACS wall charts of Phase Equilibrium Diagrams it is not a =
difficult task to predict which primary minerals will crystallise from a =
slow cooling melt. These large scale diagrams are available to all =
potters at a relatively low cost and the information they contain is =
accessible without specialist geological knowledge.
Best regards,
Ivor Lewis. Redhill, South Australia.
Richard Aerni on thu 4 apr 02
Ivor,
I always value your thoughts. Could you provide a more specific reference
about those ACS phase diagrams, and perhaps suggest a book on metamorphism?
Concerning metamorphism, I was also under the impression that pressure, as
well as heat, were ingredients in that process. I'm not sure there is an
exact analagous relationship between either igneous or metamorphic
processes, but in general, getting familiar with them is bound to help
understand mineral interactions, it would seem. And then, it's fun to read
them, too.
Best,
Richard Aerni
Bloomfield, NY
----- Original Message -----
Well, this seems a logical thing to do if the mixtures being energised to
Cone 10 conform to principles of Igneous Chemistry. But we are not dealing
with Elemental Magma situations. Many people use lower temperatures and do
not subject their materials to high pressures. More over they may be using
blends which might be mutually exclusive in a natural setting. Further more,
as I understand things, many of the ingredients in a Magma which influences
the outcome, commonly considered to be volatile components, are absent from
many glaze recipes. Perhaps a study of Metamorphism and its associated
chemistries would be more appropriate. Certainly the firing of clay is low
level metamorphism and I suppose the melting of a glaze recipe at
atmospheric pressure is as well.
Given a set of ACS wall charts of Phase Equilibrium Diagrams it is not a
difficult task to predict which primary minerals will crystallise from a
slow cooling melt. These large scale diagrams are available to all potters
at a relatively low cost and the information they contain is accessible
without specialist geological knowledge.
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