CINDI ANDERSON on sun 4 feb 01
Hi
I've been reading all the posts on glazes, and as I get ready to begin mixing and
formulating my own glazes, I find myself a little mixed up. I'm sure one of you
that has gone through this can clear it up in no time.
Basically I am sorting through the different methods for glaze formulation.
There are the computer programs. Based on all the previous posts, I get the
concepts of what these do, making sure you have the right ratios of materials to
ensure that a glaze with work right. But do all these programs work on the same
principles? (In fact, if someone has done a comparative study of several of the
glaze programs that would be awesome to see!)
Then there is "line blending" which I understand Ian Currie's techniques are based
on. But it's not clear to me exactly what that means.
There is the method that uses the Tri-axial board (the triangle thing with the
cups).
Maybe these are all variations on a theme, or maybe they are coming at it from
different angles...
Thanks for any information. I'm going to start getting books and taking some
classes on glaze formation, and I want to make sure I understand the different
methodologies to know which one I want.
Cindi
Fremont, CA
Where it's like summertime today... Great place to live if only about a million
other people would leave!
Paul Lewing on mon 5 feb 01
Cindi,
The best advice for you someone has already given, about comparing glaze
calculation programs. Get Rick Malmgren's most recent article. To the
best of my knowledge, that would be the over-the-summer issue of
Ceramics Monthly for 1998 (or '99?). Rick is the only person I've ever
heard of who has seen and run all of the programs that are available.
That said, all the programs do basically the same set of things, all of
which are just really fast ways of doing the same math that Seger
invented in the 1830's. They convert recipes to formulas, and back
again. They generate a ratio of glassformer to stabilizers, a
coefficient of expansion, a molecular weight, a percentage by weight
analysis, and a cost per kilo. And they all allow you to change and add
to the databases. Beyond that, each will have its own peculiar other
features, like inventory tracking, sorting recipes, surface tension
index or viscosity index. What works best for you depends on what you
like to do with your glaze recipes. Personally, I find programs that
only show me one recipe at a time very annoying.
And for those of you going to NCECA, I will be leading a discussion
group on using glaze software on Thursday afternoon. Drop by and meet
program users and shoppers, and find out what problems and successes
people are having.
Line blends, on the other hand, are ways of maknig and modifying glazes
if you don't know the analyses, or don't care. Basically you mix
samples and add stuff to them in a systematic way, in even gradations
from mixture A to mixture B.
Triaxials are also the same kind of blending systems, except that
instead of having points on a line between two mixtures, you have a
triangular grid. Each side is a line blend, and any point where lines
drawn parallel to the sides intersect, is some blend of each of the
three corner points.
This is not what someone else referred to as a triaxial phase diagram,
which is also a triangular graph, so it looks pretty identical. A phase
diagram is a triangular graph of one formula, and the three sides are
the fluxes, the stabilizers, and the glassformers. It's just a
pictorial representation of the Seger formula.
Both the Seger method and the mixing method can be used to both invent
and modify glazes. I think, for most potters, it's easier to come up
with new glazes by mixing. But if you know what you're doing, fixing
problems is easier with the Seger method. It's why Ron Roy has his job
and we don't.
It's like designing a diet for yourself, either by keeping track of what
food you eat and how your health goes, or starting with nutritional
requirements and then deciding what food will get that for you. They
both work, they just approach it from a different angle.
I hope this helps.
Paul Lewing, Seattle, whose wife is away on a business trip, if you
couldn't tell from the longwindedness.
Tom Buck on mon 5 feb 01
Cindi Anderson:
The technology you seek is called Theory of Glazes (or Glaze
Theory) and the general principles were published more than a Century ago
by Hermann Seger, of Germany. Most modern ceramics stem from his research.
All current glaze calculation programs make use of Seger's
approach, and require a List of Material Analyses. When the calculation is
executed, the "answer" provides the recipe designer with the glaze's Seger
(aka unity) Formula. A Table of Limits (in foreground or background)
provides a guideline for the likelihood that a particular mix will
succeed.
Which doesn't exclude glazes derived by trial and error methods.
In one sense, this is what Ian Currie does when he fires a set of tests
all at once using a precise blending method. A key advantage of Currie's
approach is that specific material analyses are not needed (but are not
ignored if the anaylses are available).
The Triaxial Diagram, sometimes called a "phase" diagram, is a
variant of the Seger Formula that offers a visual depiction of the glaze
being studied. One needs experience with reading Seger Formulas since
their meaning is not intuitive, whereas one can read a Triax more easily
and have a notion what adjustments may be needed.
If you want comparisons of the various GlzCalc programs available
seek out the articles written by Ric Malmgren, especially his recent ones.
good designs. bye. Peace. Tom B.
Tom Buck )
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
Mayssan1@AOL.COM on mon 5 feb 01
Dear Cindi:
I am in the same boat, but I think it is getting clearer after I did the
Glaze Teach on Matix http://www.matrix2000.co.nz/GlazeTeach/ It was simple
and a good starting point.
It also was simple without relying too much on previous knowledge in
chemistry.
Good luck, I hope that helps.
David Hendley on mon 5 feb 01
Cindi, good for you for wanting to learn how to formulate glazes.
Taken down to the basics, there are, in my mind, 3 basic
approaches to glaze formulation. All have value.
1) The 'shot on the dark' approach. Take a known glaze recipe
and using your knowledge of materials, guess at what to change
to get what you want.
2) The 'organized try it and see' approach. Line blends, tri-axial
blends, and the grid method are all in this category. Basically,
you decide on a set of ingredients and systematically vary the
proportions, fire, and see what you get.
3) Glaze calculation. The first 2 methods rely on manipulating
glaze materials. In glaze calculation, you change the molecules
that make up the materials, and then translate that back to
actual materials. This can be done by hand, but requires a lot of
tedious arithmetic. Computer programs eliminate the math.
There are generally accepted 'limit formulas' that, through
testing over time are known to make good glazes. They are expressed
on the molecular level, so you can compare your new glaze to
the limit formulas to get a good idea as to what it will be like.
You still have to fire and see what you get!
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: CINDI ANDERSON
To:
Sent: Sunday, February 04, 2001 2:57 PM
Subject: Different glaze formulation methods
| Hi
| I've been reading all the posts on glazes, and as I get ready to begin
mixing and
| formulating my own glazes, I find myself a little mixed up. I'm sure one
of you
| that has gone through this can clear it up in no time.
|
| Basically I am sorting through the different methods for glaze
formulation.
|
| There are the computer programs. Based on all the previous posts, I get
the
| concepts of what these do, making sure you have the right ratios of
materials to
| ensure that a glaze with work right. But do all these programs work on
the same
| principles? (In fact, if someone has done a comparative study of several
of the
| glaze programs that would be awesome to see!)
|
| Then there is "line blending" which I understand Ian Currie's techniques
are based
| on. But it's not clear to me exactly what that means.
|
| There is the method that uses the Tri-axial board (the triangle thing with
the
| cups).
|
| Maybe these are all variations on a theme, or maybe they are coming at it
from
| different angles...
|
| Thanks for any information. I'm going to start getting books and taking
some
| classes on glaze formation, and I want to make sure I understand the
different
| methodologies to know which one I want.
|
| Cindi
| Fremont, CA
Ron Roy on fri 9 feb 01
Hi Cindy,
I have been watching the answers to your questions and you are getting good
information but there are a few more points to add.
I use calculation and line blending when working on some glazes. Line
blending does have advantages and I think we should all use it for some
aspects of glaze formulation. It is particularly useful in conjunction with
calculation for "seeing" what happens when one oxide is increased or
decreased even when that oxide is gotten from a variety of materials. There
is no other way to "count" molecules like that.
Calculation can be used to give some idea of durability, forecast surface,
and most importantly substitute one material for another. Replacing GB with
frit for instance.
I use calculation for fixing fit problems as well - I find it most useful
for that particular task.
When I see a recipe I may be interested I can tell from the calculated
expansion - 90% of the time - if it will be a problem. I can then do the
original and another version with the expansion altered and line blend the
two.
Of the two methods I find the calculation most useful. I work for clay
companies and solve customer glaze problems. If I had to rely on blending
to do it I would be ineffective.
Line blending requires little learning and a lot of doing. Calculation
requires lots of learning and is more precise. I think you should do both
but if you have to choose only one I would say calculation but don't do it
by hand - it will be a much better tool if you use a calculator.
RR
>I've been reading all the posts on glazes, and as I get ready to begin
>mixing and
>formulating my own glazes, I find myself a little mixed up. I'm sure one
>of you
>that has gone through this can clear it up in no time.
>
>Basically I am sorting through the different methods for glaze formulation.
>
>There are the computer programs. Based on all the previous posts, I get the
>concepts of what these do, making sure you have the right ratios of
>materials to
>ensure that a glaze with work right. But do all these programs work on
>the same
>principles? (In fact, if someone has done a comparative study of several
>of the
>glaze programs that would be awesome to see!)
>
>Then there is "line blending" which I understand Ian Currie's techniques
>are based
>on. But it's not clear to me exactly what that means.
>
>There is the method that uses the Tri-axial board (the triangle thing with the
>cups). Maybe these are all variations on a theme, or maybe they are coming
>at it from
>different angles...
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
Tony Hansen on mon 19 feb 01
I read messages in this thread with some interest. But I'm
not sure I agree with classifying recipe testing, material
blending, or calculation to 'achieve certain ratios' as
simply alternative approaches to glaze making.
We often get calls from frustrated 'recipe junkies' and
material blenders who say, in effect, "I'm ready to learn
why" glazes do what they do. They have realized that
chemistry is a missing piece of the "understanding how
glazes work" puzzle. Also while calculation programs make it
easy to convert between recipe and formula, with some it is
the focus and with others it is a capability while the focus
is on recipe management. Each program reflects the
philosophy of its writer and even instructs in his/her
priorities.
Are not the recipe testing, material blending and
calculation methods 'stages' we go through rather than
approches to glazemaking? Do I have these statements in
correct cronological order:
-I tried a really good textbook glaze.
-It didn't work so I am looking for another.
-I've mixed hundreds of recipes, nothing works the way I want.
-I did some line and triaxial blends and got some great
looking glazes.
-I've developed a glaze that is a joy to use and apply.
-I now understand why each material is in my recipe.
-When I see glaze recipes now I see "mechanisms" that I can
transplant into my own base recipes.
-I now understand why each oxide is in the fired glaze and I
can juggle them to control properties like expansion,
hardness, leach resistance, chemistry dependent color,
gloss.
When a glaze is not working right the chemist has the extra
tools needed to fix it. A good recipe balances ten different
variables (only one of which is appearance), wrapping your
mind around these without knowing the function of oxides in
the fired glass would be difficult indeed.
==============================================
T o n y H a n s e n thansen@digitalfire.com
D I G I T A L F I R E C O R P O R A T I O N
http://digitalfire.com Bringing Ceramic Chemistry Within Reach of Anyone
Louis Katz on tue 20 feb 01
People make glazes for all kinds of reasons, just as people make pots for all
kinds of reasons. For some, potmaking is an escape, perhaps symbolic, from mass
marketed hi tech wares to a more "in tume with the earth" approach.
For these people line blends of wood ash and backyard clay make much more sense
than glaze calculation. I certainly have a bit of this in me.
I used to tell students that glazes calculated with a slide rule were more
beautiful. Denying the difference is denying the obvious, they may look the same
but one is calculated with a slide rule. Just as identical pots, one fired in a
wood kiln and one fired in gas are different. " I bought a pot fired with wood".
I will admit to not knowing a smidge as much about how to compound a glaze from
oxides as Tony or Ron, but I think that the approach someone uses can and often is
telling of thier reasons for making pots.
Louis
David Hendley on tue 20 feb 01
| Are not the recipe testing, material blending and
| calculation methods 'stages' we go through rather than
| approaches to glazemaking?
Tony, I would disagree with this premise because you've
left out the fourth, and final, "stage":
"I am now familiar and comfortable with all these methods,
and, depending on the circumstances, I can choose which
method to use."
Like you, calculation is usually my preferred way of working,
but it's pretty worthless when I want to make a glaze out
of clay from my creek and some local volcanic ash I found.
Material blending is much more appropriate here.
And yes, although I'm not a "recipe junkie", I still
occasionally like to try a recipe from a friend. If the test
looks promising, I can then look at the unity formula to see
what I've really got.
Then, there is the whole area of color development,
which is not even addressed when working with molecular
formulas and calculating glazes.
Clearly, the best position is to be comfortable using any
and all formulation methods.
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: Tony Hansen
To:
Sent: Tuesday, February 20, 2001 1:21 AM
Subject: Different glaze formulation methods
| I read messages in this thread with some interest. But I'm
| not sure I agree with classifying recipe testing, material
| blending, or calculation to 'achieve certain ratios' as
| simply alternative approaches to glaze making.
|
| We often get calls from frustrated 'recipe junkies' and
| material blenders who say, in effect, "I'm ready to learn
| why" glazes do what they do. They have realized that
| chemistry is a missing piece of the "understanding how
| glazes work" puzzle. Also while calculation programs make it
| easy to convert between recipe and formula, with some it is
| the focus and with others it is a capability while the focus
| is on recipe management. Each program reflects the
| philosophy of its writer and even instructs in his/her
| priorities.
|
| Are not the recipe testing, material blending and
| calculation methods 'stages' we go through rather than
| approches to glazemaking? Do I have these statements in
| correct cronological order:
|
| -I tried a really good textbook glaze.
| -It didn't work so I am looking for another.
| -I've mixed hundreds of recipes, nothing works the way I want.
| -I did some line and triaxial blends and got some great
| looking glazes.
| -I've developed a glaze that is a joy to use and apply.
| -I now understand why each material is in my recipe.
| -When I see glaze recipes now I see "mechanisms" that I can
| transplant into my own base recipes.
| -I now understand why each oxide is in the fired glaze and I
| can juggle them to control properties like expansion,
| hardness, leach resistance, chemistry dependent color,
| gloss.
|
| When a glaze is not working right the chemist has the extra
| tools needed to fix it. A good recipe balances ten different
| variables (only one of which is appearance), wrapping your
| mind around these without knowing the function of oxides in
| the fired glass would be difficult indeed.
|
| ==============================================
| T o n y H a n s e n thansen@digitalfire.com
| D I G I T A L F I R E C O R P O R A T I O N
| http://digitalfire.com Bringing Ceramic Chemistry Within Reach of Anyone
Tony Hansen on wed 21 feb 01
> Like you, calculation is usually my preferred way of working,
> but it's pretty worthless when I want to make a glaze out
> of clay from my creek and some local volcanic ash I found.
> Material blending is much more appropriate here.
Because chemistry information is lacking in such circumstances
then important pieces of the puzzle are missing and one has to
accept that. However for $30-50 you can get the material analyzed
and then have a much better picture. Predicting things like hardness,
leaching resistance would be very difficult. If glazes are going to be
used on functional ware I want chemistry information. I remember
having an analysis done on a volcanic ash I was using from a nearby
quarry some years ago. I had had weeks of failure trying to get
a glaze to work with it. With the analysis I was able to create a recipe
in the computer using 60% of the ash and it fired a beautiful oatmeal
silky matte on the first test.
>Then, there is the whole area of color development,
>which is not even addressed when working with molecular
>formulas and calculating glazes.
Is not color in ceramics fundamentally a matter of chemistry? You can put
a chrome-tin pink stain into a glaze but it won't fire pink unless the
chemistry
of the host glaze is sympathetic. Different host glazes will give different
shades pink. Other color systems are also persnickety like this. The
development of different colors in different non-crystalline glazes using
the same coloring oxide is invariably best explained in terms of the
chemistry of the host glazes. Stain companies really get into chemistry
issues in glazes. Explaining issues involving depth and intensity of color
are best done in chemistry terms. Understanding colors created by micro
and macro crystals cannot be done fully without understanding the chemistry
(and firing) of the glaze. However chemistry alone cannot adequately explain
color effects in variegated glazes. You also need to talk about the
mineralogy, particle size, and firing of the materials involved.
I really agree with your statement that we really need all three approaches.
====================================================
T o n y H a n s e n thansen@digitalfire.com
D I G I T A L F I R E C O R P O R A T I O N
http://digitalfire.com Calculation/Database Software for Ceramic Industry
| |
|
