Barbara J-in toasty warm Mesa, Az on thu 30 may 96
I've heard about the Insight glaze calc software, but I'm not sure if this
is for someone like myself, new in ceramics and barely coping with the
new computer technology. I don't mix a lot of my own glazes yet, but if
I were start mixing them myself would this software be simple enough for
a BEGINNER? The glaze making process can be really confusing, maybe I
should stick with premixed glazes??
Thanks,
Mert & Holly Kilpatrick on sat 5 feb 00
Peter,
I use GlazeChem. It is shareware. I don't think it has all the bells and
whistles of Insight or Matrix, but it is very
useful, I wouldn't want to do without it. It is by Robert Wilt and you can
get it from his website:
http://www.mdc.net/~rjwilt/software/index.htm
The only problem I ever have with it, if you open many windows, it will
crash. Therefore, you have to save each time after changing or adding a
glaze. Not a big deal.
Holly
>Date: Thu, 3 Feb 2000 13:19:35 EST
> >From: Peter Jones
> >Subject: Re: Quartz and cristobalite problems
> >MIME-Version: 1.0
> >Content-Type: TEXT/PLAIN; charset=US-ASCII
> >Content-Transfer-Encoding: 7BIT
> >
> >----------------------------Original message----------------------------
> >Is there a glaze/clay calculation software program out there that people
use
> >which is freeware/shareware? I'd like to find one if there is. Any
> >suggestions would be appreciated.
> >
> >Peter Jones
> >
>
Dewitt on sun 6 feb 00
I've never had a problem with GlazeChem crashing and have run it with at
least 8 to 10 windows open. Probably a good idea to save your changes
often in any case though.
I found GlazeChem useful enough to send Robert the registration fee of, I
think, $29.
deg
>----------------------------Original message----------------------------
>Peter,
>I use GlazeChem. It is shareware. I don't think it has all the bells and
>whistles of Insight or Matrix, but it is very
>useful, I wouldn't want to do without it. It is by Robert Wilt and you can
>get it from his website:
>
>http://www.mdc.net/~rjwilt/software/index.htm
>
>The only problem I ever have with it, if you open many windows, it will
>crash. Therefore, you have to save each time after changing or adding a
>glaze. Not a big deal.
>Holly
John Hesselberth on thu 10 feb 05
On Wednesday, February 9, 2005, at 10:02 PM, Ivor and Olive Lewis
wrote:
> I am highly suspicious of those given for
> pure oxides and would like to know how values for Potassium monoxide,
> Sodium monoxide, Boron oxide and Lead monoxide were obtained, given
> the thermal instability and chemical reactivity of these compounds.
Hello Ivor,
I think all of us who use COE calculations know that they are
approximations and only useful to provide direction. A problem that you
haven't mentioned is that we calculate a glaze COE by using what I know
as "the rule of mixtures". That is, of course, a simplification much
like the perfect gas law. And of course we are applying that rule of
mixtures to measured COEs of oxides that probably don't exist as such
in a glass.
All that said it has been proven to be a valuable tool in helping to
solve glaze/clay body fit problems, particularly for glossy glazes. I
think the Figure 5.5 and the words that describe it in Ron's and my
book makes that point pretty well. I would also point out that we are
really only interested in the relatively straight part of the curve. In
the curvy parts the glaze is starting to soften and move and stresses
are probably not building up between the glaze and the clay body to any
significant degree. So using the slope of the relatively straight part
of the curve as the COE doesn't bother me in the least.
One of the best summaries of all this is on David Hewett's web site at:
http://dhpot.demon.co.uk/crazing.htm.
I think I remember that he gives references to the original articles so
you can look them up to satisfy your curiosity on how the measurements
were made.
Regards,
John
>
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ivor and Olive Lewis on fri 11 feb 05
Dear John Hessleberth,
Thank you for that information.
Then the figures you get from your calculation is a relative
indication and not an absolute value.
So, can the same proportional formula that you are using in your
calculation be used to calculate the relative Coef of Exp of a fired
clay body? If it is, could you provide an example.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
John Hesselberth on fri 11 feb 05
Hi Ivor,
In my limited experience the calculations done on clay bodies are not
comparable to those done on glazes. They may still be useful on a
relative basis to compare one clay body to another, but probably not
to compare a clay body to a glaze. Ron would have more information on
that, but he is off-list for a couple more weeks. I know he prefers
measured values for clay bodies so it may be that he has seen some
anomalies between measured and calculated. Or maybe Jon Pacini can give
you a better answer.
Regards,
John
On Friday, February 11, 2005, at 01:00 AM, Ivor and Olive Lewis wrote:
> So, can the same proportional formula that you are using in your
> calculation be used to calculate the relative Coef of Exp of a fired
> clay body? If it is, could you provide an example.
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Paul Lewing on sun 13 feb 05
on 2/13/05 4:37 AM, David Hewitt at davidhewitt@DHPOT.DEMON.CO.UK wrote:
> In my limited experience the calculations done on clay bodies are not
>> comparable to those done on glazes. They may still be useful on a
>> relative basis to compare one clay body to another, but probably not
>> to compare a clay body to a glaze.
My experience with clay body analysis is probably even more limited than
John's and I'm certain it's WAY more limited than Ron's, but I'd like to
make one suggestion.
The whole Seger formula system of analysis is based on the concept that what
makes one glaze different from another, and what you really want to know
about, is the flux balance. So the fluxes are made to add up to one
(unity). That's not true in clay bodies, as there are only tiny amounts of
the fluxes, and they have very little effect. What you really care about
in a clay body is alumina. Insight is the only program I know of that
allows you to set the alumina to unity, and compare clay bodies that way.
I've never used that, but it would seem to be a more appropriate system.
However, I'd expect it to be kind of a makeshift way of analyzing clays.
Paul Lewing, Seattle
David Hewitt on sun 13 feb 05
John,
It is my understanding that the oxide expansion coefficients and the
subsequent calculation of a glaze COE assume that you all the oxides go
into the melt.
As the clay body does not reach this state the coefficients cannot be
applied to clay bodies.
Fortunately many supplies now publish a COE for their clays and this is
what we should encourage. I presume that they would obtain their figures
from dilatometer tests.
David
In message , John Hesselberth writes
>Hi Ivor,
>
>In my limited experience the calculations done on clay bodies are not
>comparable to those done on glazes. They may still be useful on a
>relative basis to compare one clay body to another, but probably not
>to compare a clay body to a glaze. Ron would have more information on
>that, but he is off-list for a couple more weeks. I know he prefers
>measured values for clay bodies so it may be that he has seen some
>anomalies between measured and calculated. Or maybe Jon Pacini can give
>you a better answer.
>
>Regards,
>
>John
>
>
>On Friday, February 11, 2005, at 01:00 AM, Ivor and Olive Lewis wrote:
>
>> So, can the same proportional formula that you are using in your
>> calculation be used to calculate the relative Coef of Exp of a fired
>> clay body? If it is, could you provide an example.
>John Hesselberth
>http://www.frogpondpottery.com
>http://www.masteringglazes.com
--
David Hewitt
Web:- http://www.dhpot.demon.co.uk
John Hesselberth on sun 13 feb 05
Hi David,
I don't disagree with you; however, not all the published values for
clay bodies are from dilatometer tests. There is at least one clay body
manufacturer that publishe (on request) calculated values. I am only
aware of three manufacturers in North America that have measured their
clay bodies with dilatometers--Tucker, Laguna, and Axner. If there are
others I would invite them to let the list know.
Regards,
John
On Sunday, February 13, 2005, at 07:37 AM, David Hewitt wrote:
> Fortunately many supplies now publish a COE for their clays and this
> is what we should encourage. I presume that they would obtain their
> figures from dilatometer tests.
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
John Hesselberth on wed 16 feb 05
On Wednesday, February 16, 2005, at 11:20 AM, David Hewitt wrote:
> The following is the reply that I have received from Potclays to the
> enquiry as to whether or not their clay body expansion figures are
> from dilatometer tests or from calculations
Hi David,
I haven't responded because I am no longer certain which clay supplier
was sending out calculated numbers on request. I know a couple it was
not, but can't remember who. But the numbers were identified as
calculated. A person I was consulting with told me of this at the time
a couple years ago. I'd bet they were just putting their clay body into
a glaze calc program and getting a number. And I suspect that could
give you relative numbers that might be useful in adjusting a body--I
have no data regarding that--just a hunch.
I would also point out that I challenged any other clay body
manufacturers who actually measure the expansion of their bodies to
speak up. I'm pretty certain several clay body manufacturers monitor
the list. Have you noticed how quiet it has been?
So I'll ask again. If any clay body manufacturers have dilatometer
results for their bodies that they will send to customers on request
please speak up. I'm relatively sure it will get you some added
business.
Regards,
John
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ron Roy on mon 21 feb 05
Hi David and Paul,
I do use calcualation for duplicating and assessing clay bodies - comparing
them with the data I have accumulated over the years - and find it very
useful. In fact I can say it is the difference between trying to find
something in the dark as opposed to daylight.
I don't bother to use alumina unity - just flux unity as always - whatever
system you use becomes useful in time I think. After all what we are doing
is comparing results and it does work for clay bodies as long as you take
into account firing conditions - iron fluxing in reduction for instance.
With clay bodies you really are comparing amounts of alumina and silica -
get them right along with amounts of iron and you can be pretty sure you
will get what you need.
The one exception is expansion - remember - calculated expansion only works
for shiny glazes - not matte glazes - and certainly not clay bodies.
RR
>>Date: Sun, 13 Feb 2005 15:48:57 -0800
>>Reply-To: Clayart
>>Sender: Clayart
>>From: Paul Lewing
>>Subject: Re: Glaze calc software
>>To: CLAYART@LSV.CERAMICS.ORG
>>on 2/13/05 4:37 AM, David Hewitt at davidhewitt@DHPOT.DEMON.CO.UK wrote:
>>
>>> In my limited experience the calculations done on clay bodies are not
>>>> comparable to those done on glazes. They may still be useful on a
>>>> relative basis to compare one clay body to another, but probably not
>>>> to compare a clay body to a glaze.
>>
>>My experience with clay body analysis is probably even more limited than
>>John's and I'm certain it's WAY more limited than Ron's, but I'd like to
>>make one suggestion.
>>The whole Seger formula system of analysis is based on the concept that what
>>makes one glaze different from another, and what you really want to know
>>about, is the flux balance. So the fluxes are made to add up to one
>>(unity). That's not true in clay bodies, as there are only tiny amounts of
>>the fluxes, and they have very little effect. What you really care about
>>in a clay body is alumina. Insight is the only program I know of that
>>allows you to set the alumina to unity, and compare clay bodies that way.
>>I've never used that, but it would seem to be a more appropriate system.
>>However, I'd expect it to be kind of a makeshift way of analyzing clays.
>>Paul Lewing, Seattle
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
David Hendley on wed 20 apr 05
I agree with Jonathan - you can't get the full use and value from a
glaze calculation program unless you first learn basic chemistry and
glaze theory.
And, yes, it is much better to learn to do glaze calculation by hand
(a calculator is fine - long division is not necessary) before you use
the computer programs.
By the same token, I'm assuming that you can do long division by
hand - one should learn to do long division without a calculator - it
just helps in the understanding of the process.
Likewise, children should also learn how to tell time with an analog
watch with hands, not just how to read numbers on a digital watch.
It changes the way you perceive temporal relationships and gives a
better understanding of how time is divided into segments.
Another reason for learning to do things in a "low tech" way is because
it gives you a feeling for what the proper answer should be. All it takes
is hitting a wrong button, and a calculator or computer program will
display a wildly wrong answer. This knowledge will enable you to
instantly know it is wrong, rather than blindly accept the answer.
David Hendley
I don't know nothin' but the blues, cobalt that is.
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
> My take on all the glaze software programs out there is that they
> presume some basic user knowledge or understanding of not only how they
> work but some basic chemistry also. By themselves, all the programs,
> are relatively useless unless there is some basic user knowledge.
Ron Roy on fri 22 apr 05
Hi David,
While I have to agree that doing calculations by hand gives an
understanding of the process - I still don't understand how it helps anyone
in understanding how clazes work.
I learned the hard way - and i use calculation everyday and cannot how - in
what way it helps me when adjusting glazes for instance.
I could never get the same answer twice doing it by hand (with a slide rule.)
How would being able to do it by hand help me get a feeling for the right
numbers to expect. Would not that happen over time using a calculator.
I'm not absolutly convinced there is no value in learning to do
calculations with out a program - it made no difference to me - I would
like to know how you think it would help.
RR
>And, yes, it is much better to learn to do glaze calculation by hand
>(a calculator is fine - long division is not necessary) before you use
>the computer programs.
>By the same token, I'm assuming that you can do long division by
>hand - one should learn to do long division without a calculator - it
>just helps in the understanding of the process.
>Another reason for learning to do things in a "low tech" way is because
>it gives you a feeling for what the proper answer should be. All it takes
>is hitting a wrong button, and a calculator or computer program will
>display a wildly wrong answer. This knowledge will enable you to
>instantly know it is wrong, rather than blindly accept the answer.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Daniel Semler on sat 23 apr 05
Hi All,
So I've been trying to answer the question, what did I learn by doing glaze
calc. manually that helped me out, that perhaps I would not have learned had I
done it first with software. I only really learnt glaze calculation last year.
I did do it manually first, and with help from John Hesselberth.
Why did I bother ?
I like to understand. Simple. Anyone who has read my testing posts will know
that. I just want to understand.
What I did.
I took a series of glaze recipes and started calculating molecular formulae
for them. The aim was to do about a dozen or so glazes that I use at the Foster
city studio. I was then going to derive from that set of numbers, limit formulae
for cone 10 glazes. I took the material analyses from Digitalfire's website and
I tried to follow Rhodes method. The first thing I did was grab a periodic
table and built up the oxide weights. I then used these weights to work through
converting the recipes with the analyses. I got stumped on a couple of points
which John H. set me straight on. He also helped me with a second method, the
one Lili referred to briefly in her post. I was then able to return to the
method published by Rhodes (and others) and complete it. I never really liked
the simplified examples that those texts used, and bashed my head against this
with real glazes I used. I did not use a calculator or pencil much. I used the
modern equivalent, a spreadsheet. Actually, I think I was sufficiently insane
to try calculating expansion at one point too.
What I learned.
What alumina unity is and why its used for clays, thanx also to Tony Hansen.
That using flux unity for clays is possible if you are prepared to work them
out. I was and did. Very confusing because the formula weight is VERY high. But
the overall answer is the same.
That silica can't use either flux or alumina unity, for our purposes.
What actual atoms comprise what oxides, what oxides are in which materials.
When you've got to make up equations to add all this stuff up you get familiar
with which cell has to contain what formula, and what it means.
What LOI is and how in some cases its identified and in some cases it goes
up the spout and there is no classification of it as a material.
Then I got to developing limit formulae found that what I had developed was
not a "limit" but rather what I like to think of as a characteristic formula.
It describes the ratios likely in glazes that are similar to those in my group.
John H. has a great paper on this, and it helped here.
That molecular weight might actually be a poor name, but oh well, I'm not a
chemist.
That the molecular weight depends on the formula you use, which depends on
your choice of unity. I now prefer the term Formula Equivalent Weight (FEW).
Would I have learned these things without doing it manually ?
I think that things like LOI and limits and so on. Sure in time. Other
things like alumina unity and FEW, perhaps not for a long time, perhaps never.
Has it helped me use the software better ?
I don't honestly know. I have much better understanding of what the software
is doing and I like that. I certainly picked up materials knowledge and that
really helps, particularly when working from a formula back to a recipe. In
many cases I think I simply prefer to re-invent the wheel. I then appreciate
that its round, why its round and so on.
Do I make better glazes as a result ?
I don't know. There's many a slip 'twixt calc. and glaze bucket. I make
glazes that I know more about perhaps. I have too far to go yet I guess. Is
this more true because I started manually ? hmmm...
I hope this helps shed some light on what a rookie glaze junkie got out of doing
it manually. What kept me at it was curiosity and a desire to really grasp the
thing. Maybe that's good enough for me.
And that's probably enough from me too.
Goodnight
D
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