Cindy Strnad on mon 22 oct 01
Dear David,
You say frits aren't available in your area. Where
do you live? Ababi in Israel, Alisa in Denmark,
Toni in South Africa, Ivor in Austraila can get
frits. I'll bet you can, too, but you'll probably
have to order them. There are no pottery supply
houses in Custer, SD, either. I get my glaze
ingredients from Sioux Falls and they come on a
truck, but you can probably have the folks you buy
your clay from order chemicals (including frits)
for you.
I highly recommend you try a glaze without
Gerstley Borate. There are many. Since you are new
at formulating glazes, you don't want to fool
around with converting Gerstley Borate glazes.
Have a look at Tony Hansen's educational articles
concerning glazes. You can find them at
http://www.digitalfire.com , along with lots of
other good stuff. If you want glaze recipes, try a
search through the archives. You'll find lots and
lots. Search the net--likewise, lots and lots.
Best of luck,
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
David Willhite on mon 22 oct 01
Hello,
First I'd like to thank the two Clayarters who did send me glaze recipes...
Charles Moore and Matthew Blumenthal... a thousand thanks!
My only problem is the frits used aren't available locally. (what's a
frit, I always used gerstely borate)
I'm a beginner when it comes to glazes...
call me silly, but I'm under the impression that a glaze must be specially
formulated to "fit" every different clay it's used on... Right?
I don't know glaze chemistry - I was so good at throwing, my teacher had me
skip the "intermediate" class and take the "advandced" class, thus I missed
out on Glaze Chemistry. I can throw anything I set my mind to. I've coil
thrown a 32 inch tall Roman/Greko style vase - too big for my kiln! Yeah,
I'm bragging, but apparently I don't have the right to, because I don't
know glaze chemistry.
Up until now, I had a clay and a glaze recipe that I thought worked okay,
but after a few years, I found out that it crazed and the pots absorbed
water and fell apart.
Now I'm searching for the perfect glaze for ^5 B-Mix. I'm a hobby potter
who has a different job - a full time disc jockey. I don't have a test
kiln and wouldn't know what to do with it if I did.
Any help would be greatly appreciated...
davidwillhite@hotmail.com
Matthew Blumenthal on mon 22 oct 01
Hi Dave
At this point, I think you need to tell us where you are.
Then we'll have an idea of where to direct you for help.
At 02:22 PM 10/22/2001 -0400, you wrote:
>Hello,
>
>First I'd like to thank the two Clayarters who did send me glaze recipes...
>Charles Moore and Matthew Blumenthal... a thousand thanks!
>
>My only problem is the frits used aren't available locally. (what's a
>frit, I always used gerstely borate)
>
>
>I'm a beginner when it comes to glazes...
>call me silly, but I'm under the impression that a glaze must be specially
>formulated to "fit" every different clay it's used on... Right?
>
>I don't know glaze chemistry - I was so good at throwing, my teacher had me
>skip the "intermediate" class and take the "advandced" class, thus I missed
>out on Glaze Chemistry. I can throw anything I set my mind to. I've coil
>thrown a 32 inch tall Roman/Greko style vase - too big for my kiln! Yeah,
>I'm bragging, but apparently I don't have the right to, because I don't
>know glaze chemistry.
>
>Up until now, I had a clay and a glaze recipe that I thought worked okay,
>but after a few years, I found out that it crazed and the pots absorbed
>water and fell apart.
>
>Now I'm searching for the perfect glaze for ^5 B-Mix. I'm a hobby potter
>who has a different job - a full time disc jockey. I don't have a test
>kiln and wouldn't know what to do with it if I did.
>
>Any help would be greatly appreciated...
>
>davidwillhite@hotmail.com
***********************************************
Matthew Blumenthal
Fremont CA
Potter, Guitar Player, Kayaker, and
General Computer Nut
mattblum@pacbell.net
http://www.mattegrafix.com
ICQ 12691259
***********************************************
Paul Taylor on tue 23 oct 01
Dear David
I am an avid glaze researcher . So this advise comes from someone who
finds glazes intriguing. I am going to advise you against what I do because
I think your needs could be better supplied by someone else other than your
self.
If I were you I would contact a large supplier that has a large
selection of glazes that you like. Get him to supply you with the clay that
fits the glazes he sells. And get the firing schedule of the glazes. it will
cost a bit but it will pay for it's self in the lack of disappointment. My
supplier makes some beautiful glazes and the bodies to match. I suspect that
there are suppliers all over the world selling catalog glazes they must
wonder why we all insist on making our own when they have spent a fortune on
research . The suppliers glazes should work on his clay at the temperature
he recommends . We would all like to hear if it does not. so Say you got
this advice from clayart - that will put the wind up him:).
The above advice does not exclude you from being creative with the glazes;
there is double dipping over spraying with glazes and stains that I bet no
one has tried with catalog glazes. It is funny how we on this list get
obsessed by making our own glazes when we would not expect painters to grind
and prepare there own pigment ( I do encourage it of my students but that's
for another 'list'). Also few of us potters find it worth while to dig our
own clay - any more (not since labour became so expensive and our backs
suspect). So buying glazes in is hardly selling out the Leach tradition - we
did that a long time ago (Thank god ).
My reasoning is that if you have an electric kiln and are firing it in a
standard way. There are no glazes that you yourself are going to come across
that a decent catalog won't cover; the cost will be more, but since you are
an art potter the costs will not matter as much as a production potter. The
savings will be negligible compared with the lack of risk. If you get
yourself a spray gun and compressor you will only have to buy small amounts
of glaze, which means you can buy a lot of different glazes to play with.
I am not suggesting you abandon glaze research, you can stick a test in
your kiln, along with the rest, at any time . Its just that this list gives
the impression that there are secrets wonder glazes that make bad pots good.
And a sort of snobbery against the industrial bought glaze and then an
obsession with making them ourselves even though they craze and some poison
our customers.
There are many glaze discussions on our list but the most of them have a
context of a particular effect be it shino carbon trapping or soda raku for
these effects you have to start at the beginning with a special kiln and
firing and lots of jigging around. By the sound of your letter you are
primarily interested in throwing forms and do not want to get obsessed by
obscure technologies. But I suspect you will eventually . Even so the work
you have done with the bought glazes may give you an advantage because you
will understand using glazes creatively as well as making them.
If you can not resist temptation and decide to make them your self I have
an essay on glaze fit that may help. Post me if you are interested. I wrote
it for someone who didn't agree with some of the things in it . He did not
tell me what.
By the way Gerstely borate is a natural boron calcium frit it has some
loss in firing which makes it difficult to substitute with a calcium borate
frit. As well it has a certain 'thing' about it I suspect something to do
with its particle size and crystal structure that made it very stable in
glazes. I never used it but the Americans will miss it. We use another
coalmenite in Europe, but it is very strange - liable to spit out all over
the kiln shelves. Alicia (Alishia) in Denmark did loads of tests ( in the
archive) with substitutes - just looking at her posts will tell you a lot
about glazes.
--
Regards Paul Taylor
http://www.anu.ie/westportpottery
"How can I improve my ratings" said the Media Mogul.
"Tell them that blame is the cure for anger, and that money is the cure for
greed" said Satan.
"But you don't exist" said the Media Mogul.
"So what " said Satan.
> From: David Willhite
> Reply-To: Ceramic Arts Discussion List
> Date: Mon, 22 Oct 2001 14:22:43 -0400
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Do glazes work on any clay?
>
> Hello,
>
> First I'd like to thank the two Clayarters who did send me glaze recipes...
> Charles Moore and Matthew Blumenthal... a thousand thanks!
>
> My only problem is the frits used aren't available locally. (what's a
> frit, I always used gerstely borate)
>
>
> I'm a beginner when it comes to glazes...
> call me silly, but I'm under the impression that a glaze must be specially
> formulated to "fit" every different clay it's used on... Right?
>
> I don't know glaze chemistry - I was so good at throwing, my teacher had me
> skip the "intermediate" class and take the "advandced" class, thus I missed
> out on Glaze Chemistry. I can throw anything I set my mind to. I've coil
> thrown a 32 inch tall Roman/Greko style vase - too big for my kiln! Yeah,
> I'm bragging, but apparently I don't have the right to, because I don't
> know glaze chemistry.
>
> Up until now, I had a clay and a glaze recipe that I thought worked okay,
> but after a few years, I found out that it crazed and the pots absorbed
> water and fell apart.
>
> Now I'm searching for the perfect glaze for ^5 B-Mix. I'm a hobby potter
> who has a different job - a full time disc jockey. I don't have a test
> kiln and wouldn't know what to do with it if I did.
>
> Any help would be greatly appreciated...
>
> davidwillhite@hotmail.com
>
Cindy Strnad on wed 24 oct 01
Dear Samuel,
What you're asking would be nice to know. Many of
us use commercial clay bodies for which we cannot
get the recipes. Even if we could get them,
expansion coefficients of clay bodies are much
more complex than those for glazes. Myself, I use
a clay body formulated by Dakota Potters Supply in
Sioux Falls, SD. I'll bet there are maybe three or
four potters at most on this list who use this
body. I know the shrinkage is usually 12.5%, the
vitrification is very good, it isn't really quite
a ^6 clay (more like 5 1/2), and it occasionally
contains mysterious bits of incongruous stuff
which the makers deny putting in there. I doubt if
this knowledge will help anyone much.
As for the expansion numbers of the glaze, they
vary from glaze program to glaze program and are
hard for most of us mortals to interpret. I know
that for my clay, I need somewhere around a 6.5 to
a 7.5 (on Insight). What these numbers mean, I
really don't understand in much depth.
If a glaze doesn't fit your claybody, you need to
change its expansion. This is best done using
glaze software of some kind. If your glaze crazes,
you need to lower the expansion. If it shivers,
you need to raise the expansion. You can do this
in several ways. It gets complicated. I suggest
you read up on the Insight web site for some basic
information. That's at http://www.digitalfire.com
. Go to the educational section and explore.
Best wishes,
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
Holder, Samuel on wed 24 oct 01
David wrote:
> I'm a beginner when it comes to glazes...
> call me silly, but I'm under the impression that a glaze must be specially
> formulated to "fit" every different clay it's used on... Right?
>
> Up until now, I had a clay and a glaze recipe that I thought worked okay,
> but after a few years, I found out that it crazed and the pots absorbed
> water and fell apart.
>
> Now I'm searching for the perfect glaze for ^5 B-Mix. I don't have a
test
> kiln and wouldn't know what to do with it if I did.
>
I find that I 'm in the same situation as David. I'm a hobbyist... but
also a beginner. I've been following the Clayart discussions for a few
months, collecting recipes, few of which I've tested. The group is very
concerned (...obsessed...?) with glaze composition and fit, which is
understandable... but they never, or very rarely, acknowledge the clay
body(s) that they use with a glaze. Sometimes a generic description of the
clay body is given... e.g.: buff stoneware w/speckles... Are they all the
same in terms of Glaze fit?. (probably not, given your concerns)
I've become very interested in the "creative aspects" of glazes. My
interest: once I have 3 to 6 good base glazes, how can they be modified to
get different effects, textures, colors... "imperfections for character."
So, I like David's basic idea for his data base... although his 20
questions also takes us into details that 1. most people avoid documenting
due to the tedium and 2. cannot control and must be tested for from kiln to
kiln and artist to artist anyway. Still, awareness of these things is good.
Recently there were requests for the formulas, for which I understand the
math/physics/chemical need, having studied these things in school, a long
time ago. It is understandable to me that most people will not provide
this because it is labor intensive and tedious to write this stuff up.
For the lovers of brevity, the simple minded, the impatient and the tight
scheduled among us, I believe the most simple, important and necessary
information that is missing from ClayArt's glaze descriptions is, "what
claybody was used."... particularly if they are using a commercial or
common claybody. Expansion coefficients would be a nice substitute.(?)
With regard to the "hard-core ceramists" among us who formulate or dig their
own claybodies... they will need more information and testing anyway.
Am I wrong??? ........ (please target my chest for any disagreements
:-)
Thanks
____________________________________________________________________________
__
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.
Dave Finkelnburg on fri 26 oct 01
David, Samuel,
To make this even more complicated, :-) glaze fit changes
depending on how a particular clay body is fired. A glaze that fits well on
a clay body fired in oxidation may not fit so well on the same clay body
fired to exactly the same cone in reduction. That's because iron in the
clay acts as a flux in reduction, causing some greater degree of
vitrification of the clay body.
Also, according to Robert Tichane, glaze crazing can be caused by an
underfired clay body absorbing moisture, not just by the glaze having too
high an expansion compared to the clay body. So, even knowing the clay
body used with a particular glaze is no guarantee you'll get the same fit.
You need to know the firing atmosphere.
All the best in your search for a better understanding of glazes!
Dave Finkelnburg on a gorgeously starry night in Idaho
Ron Roy on sun 28 oct 01
Hi Samuel,
You won't find many clay companies that will supply expansions for their
bodies unfortunately - but in the end that information would be hard to use
- Only measured expansion works on clay bodies. Only measured expansion of
glazes are comparable and even then - it would be better to have the actual
charts because of the silica phases - or lack of - in different clay
bodies.
There is a chapter in a book that will be available soon that explains all
this and offers a set of cone 6 glazes that will help you find the
information you need for every body you use - at what ever firing schedule
you use. You will then be able to use calculated expansion numbers from any
program - to predict glossy glaze fit.
In a few months with luck.
RR
>For the lovers of brevity, the simple minded, the impatient and the tight
>scheduled among us, I believe the most simple, important and necessary
>information that is missing from ClayArt's glaze descriptions is, "what
>claybody was used."... particularly if they are using a commercial or
>common claybody. Expansion coefficients would be a nice substitute.(?)
>With regard to the "hard-core ceramists" among us who formulate or dig their
>own claybodies... they will need more information and testing anyway.
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 sun 28 oct 01
Hello Ron. This tool you make in your book, works on clay bodies> will it be for all claybodies or north American
alone?
Thank you , Ababi
---------- Original Message ----------
>Hi Samuel,
>You won't find many clay companies that will supply expansions for their
>bodies unfortunately - but in the end that information would be hard to
>use
>- Only measured expansion works on clay bodies. Only measured expansion
>of
>glazes are comparable and even then - it would be better to have the
>actual
>charts because of the silica phases - or lack of - in different clay
>bodies.
>There is a chapter in a book that will be available soon that explains
>all
>this and offers a set of cone 6 glazes that will help you find the
>information you need for every body you use - at what ever firing
>schedule
>you use. You will then be able to use calculated expansion numbers from
>any
>program - to predict glossy glaze fit.
>In a few months with luck.
>RR
>>For the lovers of brevity, the simple minded, the impatient and the
>tight
>>scheduled among us, I believe the most simple, important and necessary
>>information that is missing from ClayArt's glaze descriptions is, "what
>>claybody was used."... particularly if they are using a commercial or
>>common claybody. Expansion coefficients would be a nice substitute.(?)
>>With regard to the "hard-core ceramists" among us who formulate or dig
>their
>>own claybodies... they will need more information and testing anyway.
>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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