Ron Roy on sun 14 jan 01
Hi Tom,
I saw that letter too - no 3124 is not a good replacement for GB for many
reasons.
3124 is the same as 3134 except it has some alumina. Given the ability for
GB to float glaze (in some cases overfloat) why would anyone suggest a frit
with alumina when you could get it without - don't you need the clay in the
glaze to help float it?
Why would you spend money to buy boron in an insoluble form (thats what you
are doing when you buy a frit to replace the boron when you take the GB
out) and buy a version of that frit with alumina and less boron.
The only reason to use frit 3124 would be if you had too much clay and
wanted to cut it down.
I just made up a cone 6 glaze with 20% GB - I had to use 44% F3124 to get
the same amount of boron - had to cut the clay and silica down and it was
still not right.
After all the time we have spent on this subject - how could anyone suggest
such a thing?
I did the same thing with 3134 and only had to use 26% to get the same
amount of boron and had to increase the clay - this is not complicated -
all one has to do is look at the analysis and think a bit.
RR
>In respect to replacement for GB. Did I understand someone to say that frit
>3124 a reasonble replacement?
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Susan Otter on mon 15 jan 01
In a message dated 1/15/01 7:17:47 PM, ronroy@POP.TOTAL.NET writes:
<< I did the same thing with 3134 and only had to use 26% to get the same
amount of boron and had to increase the clay - this is not complicated -
all one has to do is look at the analysis and think a bit.
RR
>In respect to replacement for GB. Did I understand someone to say that frit
>3124 a reasonble replacement? >>
Ron we don't all have your tremendous understanding of glazes. The whole=20
discussion has certainly piqued my interest.=A0I have found several glaze=20
recipes I would like to try that call for Gerstley Borate. I wish I had the=20
knowledge to make a sensible substitution, but I don't. I'm going to look fo=
r=20
a course I can take on the topic of clay chemistry.
Chris Schafale on mon 15 jan 01
Ron's heard this before from me, and I don't wish to be tiresome,
but I think 3124 does have its place in replacing GB, for exactly the
reason that Ron mentions in passing -- "The only reason to use frit
3124 would be if you had too much clay and wanted to cut it
down.". In my experience, many of the reformulations with 3134 do
have way too much clay in them. The drying shrinkage is terrible,
so they crack and peel and fall off the pots, especially if you try to
layer them. (At least in my studio they do -- your mileage may
vary).
Ron's right that you can't use just 3124, because you don't get
enough boron, but I find that a combination of 3124 and 3134
sometimes lets me cut the clay down to a manageable level (12-
15% works for me, floats the glaze but doesn't crack so badly) and
still have enough boron and enough alumina.
Just another point of view.
Chris
> Hi Tom,
>
> I saw that letter too - no 3124 is not a good replacement for GB for many
> reasons.
>
> 3124 is the same as 3134 except it has some alumina. Given the ability for
> GB to float glaze (in some cases overfloat) why would anyone suggest a frit
> with alumina when you could get it without - don't you need the clay in the
> glaze to help float it?
>
> Why would you spend money to buy boron in an insoluble form (thats what you
> are doing when you buy a frit to replace the boron when you take the GB
> out) and buy a version of that frit with alumina and less boron.
>
> The only reason to use frit 3124 would be if you had too much clay and
> wanted to cut it down.
>
> I just made up a cone 6 glaze with 20% GB - I had to use 44% F3124 to get
> the same amount of boron - had to cut the clay and silica down and it was
> still not right.
>
> After all the time we have spent on this subject - how could anyone suggest
> such a thing?
>
> I did the same thing with 3134 and only had to use 26% to get the same
> amount of boron and had to increase the clay - this is not complicated -
> all one has to do is look at the analysis and think a bit.
>
> RR
>
>
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
Chris Schafale on mon 15 jan 01
Susan,
You don't have to take a whole class in glaze chemistry, really!
Just download a free demo copy of Insight or one of the other glaze
calc programs and start playing! Put your original glaze in one
column and a copy of it in the other, start changing stuff in the
copy, and see what happens to the numbers. Get a copy of
Hamer and read about glaze materials. Get Ian Currie's new book
(which is WAY easier to grasp than his first one, by the way) and
do some tiles.
I haven't had a chemistry class since high school (and didn't do all
that well at it even then) and I've never had a formal class that dealt
with glaze chemistry, but I have enough of a grasp from reading
and playing and testing that I can pretty confidently reformulate a
glaze. Truly, it's not that hard -- the computer does all the work in
calculating. All you have to do is mix the glazes and carefully
observe the results.
Chris
>
>
> Ron we don't all have your tremendous understanding of glazes. The whole=
> discussion has certainly piqued my interest.=A0I have found several glaz=
e
> recipes I would like to try that call for Gerstley Borate. I wish I had =
the
> knowledge to make a sensible substitution, but I don't. I'm going to loo=
k for
> a course I can take on the topic of clay chemistry.
>
> ________________________________________________________________________=
______
> 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@pcli=
nk.com.
>
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
Susan Otter on tue 16 jan 01
In a message dated 1/16/01 4:35:01 AM, candle@INTREX.NET writes:
<< Susan,
You don't have to take a whole class in glaze chemistry, really!
Just download a free demo copy of Insight or one of the other glaze
calc programs and start playing! >>
If they run on a Mac... :/ -- the great majority of such programs do not
(please let's not go there -- there are reasons I need a Mac... smile)
I can't just "start playing," because I'm a relative beginner and don't have
my own kiln. I can make test tiles that won't be fired for three weeks.
And, while the program might well do the calculations, I would still want to
know the why of it.... This is not the sort of thing I learn well from book
alone, without instructor. We'll see, but I don't think anyone can remain
ignorant of glaze formulation any more if they want to throw. I found out a
couple of days ago that the stuff labeled Gerstley Borate in our glaze room
isn't GB but the manager's best guess of what will substitute best.
I don't have any control over firing. I am going to want to know the "whys"
of glazes.
John Hesselberth on tue 16 jan 01
Susan Otter wrote:
>
>If they run on a Mac... :/ -- the great majority of such programs do not
>(please let's not go there -- there are reasons I need a Mac... smile)
HyperGlaze is the only currently available program I am aware of that
runs on the Mac.
Matrix used to but the mac version is no longer being supported.
Insight 4.0 runs on the mac but it is my understanding it is no longer
being sold. It is a program that has a definite 1980s feel to it. I have
tried to like it, but it is just too primitive for my taste. Tony Hansen
recommends Mac owners buy one of the simulation programs like Virtual PC
and then running his Windows program Insight 5+ on that. Not many Mac
owners I know are willing to do that. He has also been promising a new
Mac version for some time but is apparently having trouble doing it.
I believe most of the shareware programs are built off spreadsheets. I
have no idea if one could port those to a Mac or not.
HyperGlaze does fine for me. The only problem I have seen is that some
of the materials are either out of date or oversimplified (e.g. I believe
the analysis for talc is the theoretical one, not the real one). I have
laboriously updated my materials stack and if anyone wants a copy of it,
email me off list.
Each of the above, by the way has its own pros and cons as nearly as I
can tell. There is no one "perfect" program.
Regards, John
"The life so short, the craft so long to learn." Hippocrates, 5th cent.
B.C.
Autumn Downey on tue 16 jan 01
Susan,
I really like having glaze programs to crunch numbers, but before I got
one, I did quite alot of reading. Started easy and moved to more difficult.
What I didn't understand, I just glossed over. Eventually, most of it made
sense. I began with the glossary at the back of Chappell's Complete Book of
Clay and Glazes.
Generally it's not a bad idea to start with a glaze you either like (or
dislike).
Look up the materials in it and see what it says about them. Write out the
oxides that the materials contribute and then read what the oxides do.
(Do a glaze a day?)
It's entirely qualitative and won't solve any problems, but it does help to
know what's in a glaze. Then when you do work with numbers, they make
more sense. (You are right, numbers alone won't do it.)
Although someone could teach you glaze theory, I think you would be better
off to learn the "ingredients" stuff at your own pace in some context that
is important to you. Otherwise, it's too much at once. And observe the
glazes you are using. Or sneak in a few tests of your own!
A good source is the glaze tutorial that's on the Ceramics Web.
http://art.sdsu.edu/ceramicsweb/
Look under class materials/tutorials (I think?). It was done by Robert
Fromme. I've printed it off to refer to.
Good luck.
Autumn Downey
Yellowknife, NWT
>I can't just "start playing," because I'm a relative beginner and don't have
>my own kiln. I can make test tiles that won't be fired for three weeks.
>
>And, while the program might well do the calculations, I would still want to
>know the why of it.... This is not the sort of thing I learn well from book
>alone, without instructor. We'll see, but I don't think anyone can remain
>ignorant of glaze formulation any more if they want to throw. I found out a
>couple of days ago that the stuff labeled Gerstley Borate in our glaze room
>isn't GB but the manager's best guess of what will substitute best.
>
>I don't have any control over firing. I am going to want to know the "whys"
>of glazes.
>
>___________________________________________________________________________
___
>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.
>
>
Cindy Strnad on tue 16 jan 01
Hi, Susan
Insight does offer a version for the Macintosh, and it includes a manual.
Also available is the Magic of Fire book, which is a companion to the
software.
Like you, I'd rather learn this sort of thing straight from the horse's
mouth, but barring the availability of that kind of opportunity, the books
and software are a lot of help. In other words, take the best you can get
and keep looking for something better in the meantime.
I don't remember what the glaze was that you wanted to reformulate? Maybe I
have something that would work for you until you get your old favorite
worked out again without the Gerstley. Let me know privately, and I'll help
if I can.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
Lawrence Ewing on tue 16 jan 01
Hi Susan,
You might like to take a look at GlazeTeach which is an online free
interactive glaze chemistry instruction course designed for people starti=
ng
out on this fascinating road of discovery. You can find it at
http://www.Matrix2000.co.nz/GlazeTeach
Regards,
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 Susan Otter
Sent: Tuesday, January 16, 2001 9:51 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: frit 3124 as replacement for GB
In a message dated 1/15/01 7:17:47 PM, ronroy@POP.TOTAL.NET writes:
<< I did the same thing with 3134 and only had to use 26% to get the same
amount of boron and had to increase the clay - this is not complicated -
all one has to do is look at the analysis and think a bit.
RR
>In respect to replacement for GB. Did I understand someone to say that f=
rit
>3124 a reasonble replacement? >>
Ron we don't all have your tremendous understanding of glazes. The whole
discussion has certainly piqued my interest.=A0I have found several glaze
recipes I would like to try that call for Gerstley Borate. I wish I had t=
he
knowledge to make a sensible substitution, but I don't. I'm going to look
for
a course I can take on the topic of clay chemistry.
_________________________________________________________________________=
___
__
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.
Lawrence Ewing on wed 17 jan 01
John Hesselberth wrote:
>HyperGlaze is the only currently available program I am aware of that
>runs on the Mac.
>Matrix used to but the mac version is no longer being supported.
In case this has caused any confusion can I clarify the current status of
the Mac version of Matrix. This software is still available and is not too
different from its PC offshoot. At present I am not able to do any further
development work on the application as I no longer have a computer on which
I can do this. I am hoping this will be a temporary situation. In the
meantime Matrix for Macs is alive and working with most of the features
which the PC version has.
Regards to all,
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 John Hesselberth
Sent: Wednesday, January 17, 2001 5:48 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: frit 3124 as replacement for GB
Susan Otter wrote:
>
>If they run on a Mac... :/ -- the great majority of such programs do not
>(please let's not go there -- there are reasons I need a Mac... smile)
HyperGlaze is the only currently available program I am aware of that
runs on the Mac.
Matrix used to but the mac version is no longer being supported.
Insight 4.0 runs on the mac but it is my understanding it is no longer
being sold. It is a program that has a definite 1980s feel to it. I have
tried to like it, but it is just too primitive for my taste. Tony Hansen
recommends Mac owners buy one of the simulation programs like Virtual PC
and then running his Windows program Insight 5+ on that. Not many Mac
owners I know are willing to do that. He has also been promising a new
Mac version for some time but is apparently having trouble doing it.
I believe most of the shareware programs are built off spreadsheets. I
have no idea if one could port those to a Mac or not.
HyperGlaze does fine for me. The only problem I have seen is that some
of the materials are either out of date or oversimplified (e.g. I believe
the analysis for talc is the theoretical one, not the real one). I have
laboriously updated my materials stack and if anyone wants a copy of it,
email me off list.
Each of the above, by the way has its own pros and cons as nearly as I
can tell. There is no one "perfect" program.
Regards, John
"The life so short, the craft so long to learn." Hippocrates, 5th cent.
B.C.
____________________________________________________________________________
__
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.
Ian Currie on thu 18 jan 01
Greetings again
I like Autumn Downey's approach. The first step is to learn what our
materials do. If we have a glaze recipe we first ask: "Why is each of these
materials here? What do they do?"
If we are not sure we can do as Autumn did and read about them and find out.
Although there are thousands (more!) of possible glaze materials, the good
news is that there are only a dozen or so oxides to learn. [The glaze
materials are composed of these dozen oxides which tend to have consistent
properties. OK so there is more to it, but the student who learns to read
what oxides are present, and what properties they bring to the glaze, is
half-way there.]
It takes longer to learn what the dozen or so oxides actually do, but we now
are able to look at a wide range of rocks, wood ashes, industrial minerals,
ceramic materials etc. and see what they will bring to the glaze.
I suggest the main problem with GB comes from its variability. Are we sure
that the GB in our bin corresponds to the analysis we are using in our
substitution calculations? And that is just the chemistry.
Then there is the physics. GB in my limited experience is gloopy stuff. A
pure frit substitution will behave differently because frits do not gloop.
Gloopiness is usually caused by the minerals containing some water (look for
H2O or -OH in the analysis). I read up on GB in "Out of the Earth, Into the
Fire" by Mimi Obstler (The American Ceramic Society). Going out on a limb
here, having so little experience with GB, but looking at what Obstler has
written, I think I would be putting a lot of bentonite into the frit
substitution. [Note: there is a misprint on page 152. "SO2 10.6%" should
read "SiO2 10.6%" I'm fairly sure.]
But no matter what we do we come back to the original problem, a problem
typical for variable materials... what if the analysis we have for the
material in our bin is wrong?
A useful "method" here used by many potters who deal with natural
materials...
Get a bin-full fo the stuff... Mix it so it is uniform... Do your tests...
Use it until it runs out.
Then get some more but do not assume it will behave the same, though it
often will!
If we are willing to do this the range of materials open to us is endless...
limited only by our ability to obtain and process the rocks, clays, wood
ashes, ochres, sludges, gloops... the full array of "mineral" material
available in the world.
Incidentally Autumn, regarding your comment about it just being
"qualitative"... after reading glaze formulae and material formulae for a
while, you will notice the big numbers (not subscripts) in front of many of
the oxides (if there is none, just understand "1"). These tell you the
proportions. They are a quantitative measure. Sure we might not understand
just what 6SiO2 means (apart from "6 molecular parts of silica") but we DO
know that it is TWICE AS MUCH silica as 3SiO2. So immediately we are able
to make "comparative" measurements. If for example you try this on the
formulae of some clays (ball clays, china clays) you will be able to see
which have more silica and which less. Comparative measurement, but very
useful.
Cheers
Ian Currie
http://ian.currie.to/
From: Autumn Downey
To: CLAYART@LSV.CERAMICS.ORG
Date: Tuesday, January 16, 2001 10:27 PM
Subject: Re: frit 3124 as replacement for GB
>Susan,
>
>I really like having glaze programs to crunch numbers, but before I got
>one, I did quite alot of reading. Started easy and moved to more difficult.
>What I didn't understand, I just glossed over. Eventually, most of it made
>sense. I began with the glossary at the back of Chappell's Complete Book of
>Clay and Glazes.
>
>Generally it's not a bad idea to start with a glaze you either like (or
>dislike).
>Look up the materials in it and see what it says about them. Write out the
>oxides that the materials contribute and then read what the oxides do.
>
>(Do a glaze a day?)
>
>It's entirely qualitative and won't solve any problems, but it does help to
>know what's in a glaze. Then when you do work with numbers, they make
>more sense. (You are right, numbers alone won't do it.)
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