Earl Krueger on sun 12 oct 03
I searched the archives, and Digitalfire web site, but did not find the
answer to what should be a fairly straightforward and logical question:
"Why are moles of molecular oxides (Na20, CaO, Si02) used in glaze
calculations instead of moles of the cations(Na+, Ca++, SI++++)?"
One answer would be "Because that's the way its always been done."
However, it's not the only way? If I look at a hypothetical glaze
consisting of:
Na2O 0.25
K2O 0.25
MgO 0.25
CaO 0.25
----
1.00
Al2O3 0.50
SiO2 3.00
and compare the ratios of molecular oxides to the ratios of cations:
Molecule Molecular Cation Cation
ratio ratio
Na2O 1 Na+ 2
K2O 1 K+ 2
MgO 1 Mg++ 1
CaO 1 Ca++ 1
---- ----
Flux 4 6
Al2O3 2 Al+++ 4
SiO2 12 Si++++ 12
we see the flux:aluminum:silicon ratios are:
molecular 4:2:12 or 1 : 0.50 : 3
cation 6:4:12 or 1 : 0.67 : 2
These ratios are considerably different.
If you accept the view of a glaze being a framework of silicon and
oxygen chains linked by aluminum with the other components of the glaze
distributed in the matrix at random, then it seems to me that certain
characteristics of the glaze would be determined by the number of atoms
rather than the number of molecular species, which most likely don't
exist as such, in the glaze.
I wonder... If we started looking at glazes in terms of the number of
atoms vs molecules would we see new relationships that would lead to
better understanding of glaze chemistry?
Earl...
Bothell, WA
Janet Kaiser on sun 12 oct 03
Oh, good grief Earl! Just when I had started actually reading the
glaze posts, thanks to the efforts of my friend Alisa, there you
have gone and done it again!
You ask why?!?!? Because in my case I blank out and become
totally brain dead as soon as the maths enters... And I am not
alone. Although Ian Currie shouted at me once for proposing
teaspoons as a valid measurement... At least they are normed,
unlike Mel's sea shells... Anything beyond that accuracy level
and you loose me, so when it comes to Seger formulas let alone
molecular science... Well... Let's just say that is an area of
glaze development I will leave to the Big Boys and Girls to play
around with.
Anyway, by nature, I am much more interested in the results of
gratuitous Serendipity versus Science... And as a gallerist, it
is also in my own interest! A beautiful "unique" glaze which
cannot be repeated? Ah... That most rare of creatures: "The
Unique Pot"... A pot pedlars dream!
But you carry on... Do not let dullards like me cramp your
style... :o)
Sincerely
Janet Kaiser -- by the way... that little emoticon :o) looks
really cute if viewed in the font it was typed in... Papyrus. I
hit it by mistake one day... More serendipidy. Lot depends on the
font though... For example it has taken me some time to realise
that Lee Love's ;^) is actually smiling! Always took it to be him
sticking his tongue out!
*** IN REPLY TO THE FOLLOWING MAIL:
>I searched the archives, and Digitalfire web site, but did not
find the
>answer to what should be a fairly straightforward and logical
question:
>"Why are moles of molecular oxides (Na20, CaO, Si02) used in
glaze
>calculations instead of moles of the cations(Na+, Ca++,
SI++++)?"
>One answer would be "Because that's the way its always been
done."
>big snip<
>I wonder... If we started looking at glazes in terms of the
number of
>atoms vs molecules would we see new relationships that would
lead to
>better understanding of glaze chemistry?
*** THE MAIL FROM Earl Krueger ENDS HERE ***
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***********************************************************
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The Chapel of Art : Capel Celfyddyd
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Tel: ++44 (01766) 523570 http://www.the-coa.org.uk
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Lee Love on mon 13 oct 03
----- Original Message -----
From: "Janet Kaiser"
> alone. Although Ian Currie shouted at me once for proposing
> teaspoons as a valid measurement...
Janet, hit Ian in the head with a wet sponge! ;^)
The teaspoon measure isn't all that strange. The
traditional measure here in Mashiko, is by the wet shaku (ladle) full.
All materials are mixed with water and kept in cement vats, crockery and
buckets as slip. Typically, the water at the top of the material is taken
off before the slip is used. In the case of glazes, the water is removed,
and then a standard beginning amount is replaced. As I mentioned before,
water is added to the glaze as the thickness of the ware increase, so when
you use the glaze again the next time, there is too much water for the thin
work that you begin with.
We mixing really makes sense here in Japan, because you are
always going to have moisture related problems with dry ingredients.
Besides, can you really measure to the milligram if you can't account for
the moisture content of the dry ingredients? A little common sense tells
you no.
Once I work out my standard glazes, I will do my mixing by the wet
shaku full. Actually, it is a safer practice as far as keeping
particulate material out of the air.
--
Lee In Mashiko, Japan
http://Mashiko.org
Web Log (click on recent date):
http://www.livejournal.com/users/togeika/calendar
iandol on mon 13 oct 03
Dear Earl Krueger,=20
I have great sympathy for your suggestion, but first we should =
critically reconsider Seger or Unity formulae and why they are now in =
common use. They are a convenient way of approaching a Glaze Recipe =
composition to reveal information that can be used to make comparisons =
and predictions. They have the advantage that they have proven =
themselves consistent and we can relate our observations to the =
information they present. There is ample evidence of this in early =
archives of the ACS.
But this way of presenting information about a glaze says nothing, in my =
opinion, about the Chemistry of the materials which are to be used or =
the materials which they become.
Without access to Dilatometer results, such as those offered generously =
by Ron Roy, it would be difficult to correlate factors like Coeff of =
Expansion to the ratios of other elements, be they expressed as =
molecular oxides or as collections of Cations and Anions.
I have a feeling that there may be a strong opinion that this is not =
really the realm of Potters and Artists. To be extreme, it might even be =
suggested that the Discipline of Glaze Chemistry or Science does not yet =
exist in the field of Studio Ceramics.
It would need people to use a vocabulary which conceals difficult =
conceptual hypotheses. It would need minds that can think with three =
dimensional models, imagination which can assemble Tetrahedra and =
Octahedra and link them with Bridging Oxygen Ions, not as chains but as =
frameworks, then allocating those free roaming Cations, fondly known as =
"Fluxes", spaces where they can embed themselves, not randomly, but =
according to their size and electronic charge. Which would get us into =
the realms of some difficult three dimensional trigonometry. But it =
could lead to answers to questions like "Why does Copper leach so =
easily" or "Why do we sometimes get such contrasting colours from =
Nickel" or "Why should some of the fluxes change from being helpful in a =
melting situation to being a hindrance"
I think you have raised an important issue, Congratulations on your =
brilliant insight. I will be watching developments.
Best regards,
Ivor Lewis. Redhill, South Australia
May Luk on wed 15 oct 03
Maybe there's a PhD thesis out there floating around on this issue.
A partial quote from the Guardian Sept 4, 2003 [News from Nature, the
international journal of science]
New periodic table invented.
A new periodic table could soon be in geology classrooms. It shows how
chemical elements are distributed in nature, sorting them by electrical
charge rather than weight.
Bruce Railsback of the University of Georgia in Athens redesigned the
periodic table after becoming tired with pointing at the original version in
class. "I marched into my office, and began working on a better table."
The Earth's minerals consist mostly of electrically charged elements, of
ions. These behave differently from the original periodic table's neutral
atoms. Railsback grouped ions with similar charge according to where they
are found, he writes in Geology. Some elements appear serveral times with
different charges. Sulphur appears four times: S, S2+, S4+, and even S6+.
Find more on the web nature.com
guardian.co.uk/life
Geologist and rock physicist have better ideas, it seems. Whether it's
molecular weight or electrical charge, we are only dealing with theory,
isn't it? An educated guess? Another model for the scientist to raise more
questions? There are effects of impurities in minerals that calculation
could never predict. This is what I gather from chatting with my uncle,
who's a chemist.
Regards
May
London, UK
Earl Krueger on wed 15 oct 03
On Wednesday, October 15, 2003, at 06:58 AM, Earl Brunner wrote:
> "Over hills, over dells, we have hit the dusty trails,
> and the cations keep rolling along......."
And some day when you have 6 or 7 hours I'll tell you my
tipp-a-rary joke.
Earl...
Bothell, WA
Ron Roy on wed 15 oct 03
Hi Earl,
I have no idea if using cations would be useful - you will need to use that
way to see if it would be.
One of the strong points of the Seger way is - because the fluxes always
add to one - then we have a handy way to evaluate firing temperature and in
may cases - durability.
I suppose there would be no reason why you could not still make the fluxes
add to one and keep the rest in proportion - is that right?
Calculated expansion - based on oxide percent is also very handy but I
again assume you could still calculate that as well.
Why not do it all 4 ways Unity, %, mol% and cation and see if you can find
some correlations.
RR
>I searched the archives, and Digitalfire web site, but did not find the
>answer to what should be a fairly straightforward and logical question:
>
>"Why are moles of molecular oxides (Na20, CaO, Si02) used in glaze
>calculations instead of moles of the cations(Na+, Ca++, SI++++)?"
>
>One answer would be "Because that's the way its always been done."
>However, it's not the only way? If I look at a hypothetical glaze
>consisting of:
>
>Na2O 0.25
>K2O 0.25
>MgO 0.25
>CaO 0.25
> ----
> 1.00
>
>Al2O3 0.50
>SiO2 3.00
>
>and compare the ratios of molecular oxides to the ratios of cations:
>
>Molecule Molecular Cation Cation
> ratio ratio
>Na2O 1 Na+ 2
>K2O 1 K+ 2
>MgO 1 Mg++ 1
>CaO 1 Ca++ 1
> ---- ----
> Flux 4 6
>
>Al2O3 2 Al+++ 4
>SiO2 12 Si++++ 12
>
>we see the flux:aluminum:silicon ratios are:
>
>molecular 4:2:12 or 1 : 0.50 : 3
>cation 6:4:12 or 1 : 0.67 : 2
>
>These ratios are considerably different.
>
>If you accept the view of a glaze being a framework of silicon and
>oxygen chains linked by aluminum with the other components of the glaze
>distributed in the matrix at random, then it seems to me that certain
>characteristics of the glaze would be determined by the number of atoms
>rather than the number of molecular species, which most likely don't
>exist as such, in the glaze.
>
>
>I wonder... If we started looking at glazes in terms of the number of
>atoms vs molecules would we see new relationships that would lead to
>better understanding of glaze chemistry?
>Earl...
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Earl Brunner on wed 15 oct 03
"Over hills, over dells, we have hit the dusty trails,
and the cations keep rolling along......."
sorry, but I thought I'd blend the two threads, music-cations......
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ron Roy
Sent: Tuesday, October 14, 2003 10:45 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Glaze calculation- Why use oxides?
Hi Earl,
I have no idea if using cations would be useful - you will need to use
that
way to see if it would be.
Ron Roy on thu 16 oct 03
Hi May,
The more complete the analysis of the materials we use - the more accurate
calculation is.
Glaze and clay calculation is far from theoretical - as anyone who has used
it sucessfully to solve problems will tell you.
There is a wonderful book by Oliver Sacks called "My Uncle Tungsten"
(memories of a chemical boyhood.)
All about the wonders of the periodic table - how it was rearranged by
Medeleev and Newlands and how Mendeleev actually predicted the discovery of
more elements because of the gaps in the periodic table. A proof that
theory can be turned into reality.
Anyone will find this book interesting - and if you are not more interested
in chemistry at the end of it - I for one will be amazed.
RR
>Geologist and rock physicist have better ideas, it seems. Whether it's
>molecular weight or electrical charge, we are only dealing with theory,
>isn't it? An educated guess? Another model for the scientist to raise more
>questions? There are effects of impurities in minerals that calculation
>could never predict. This is what I gather from chatting with my uncle,
>who's a chemist.
>May
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
May Luk on thu 16 oct 03
Hi Ron and friends,
Thanks for allowing me to particpate in this discussion. And thanks for the
book recomandation. I read good reviews in the paper.
As a student of ceramics, I guess my uncertainty stems from; lack of data
and imperfect observation. I don't know enough to dispute. The scientific
minds always want to uncover the truth. My opinion is that using math, the
chosen language for science, to explain glaze and clay is only touching
against part of the truth. It's talked about in other threads in different
ways.
If you and others would not mind, can you help me understand the thread
better.
Partial quote from first post:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you accept the view of a glaze being a framework of silicon and
oxygen chains linked by aluminum with the other components of the glaze
distributed in the matrix at random, then it seems to me that certain
characteristics of the glaze would be determined by the number of atoms
rather than the number of molecular species, which most likely don't
exist as such, in the glaze.
I wonder... If we started looking at glazes in terms of the number of
atoms vs molecules would we see new relationships that would lead to
better understanding of glaze chemistry?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I don't' quite understand the part that says "certain characteristics of
atoms rather than the number of molecular species"--The distinction between
atoms and molecular species. But, atom is part of a molecule. We need to
look closer to the finer part?
A molecule is an assembly of atoms, bound together loosely enough to be
broken up during a chemical reaction-breaking up and reforming in a
combination. In solid, atoms or molecules are close together in a fixed
position.
Is it that what Earl is proposing; What we need to "see" is the bonding of
the molecules, not the weights in number terms? Is it that using knowledge
about the size, charge and structure of ions, one can trace the movement of
atoms during chemical reactions and make prediction of the final molecular
configuration, ie; appearance and quality of the final compound [glaze]? How
tight or sturdy of a bond is related to the electrical charge amongst atoms
and the configuration. Eg; Graphite and diamond.
If that's the proposed mode of thinking, can models be built to illustrate;
like the space-filling model of a DNA in the vein of popular science? If
enough people show interest, Scientific America might do an article and show
some nice illustrations.
Or what he's proposing is another way to make calculation. And hopefully
calculating in different ways, we have another insight to the making of
glaze and clay?
Side bar: Science museums has exhibits related to ceramics; pyrometers, cone
packs, early refrigeration-an earthenware jug amongst other things. If
ceramic museums do something like that for glaze and clay in a molecular
level, it'd be jolly interesting and very educational.
Best Regards
May
London, UK
Susie Schreiber on thu 16 oct 03
> There is a wonderful book by Oliver Sacks called "My Uncle Tungsten"
> (memories of a chemical boyhood.)
>
> Anyone will find this book interesting - and if you are not more
interested
> in chemistry at the end of it - I for one will be amazed.
> RR
I loved this book. I think Oliver Sacks is a wonderful writer, and I have
enjoyed his many books and articles over the years. Anyone who doesn't think
science is fun should read "Uncle Tungsten" and be convinced otherwise! In
my case he was preaching to the choir, but I think he makes science-- and
chemistry in particular--accessible and interesting even for folks who lack
a science background.
Put this book on your reading lists!
Susie
susieschreiber@yahoo.com
iandol on fri 17 oct 03
Dear May Luk,=20
This is indeed a useful philosophical discussion. I perceive you are =
rather new to the list. If you are not you may have already got your =
head inside the pages of books I suggested as being useful reading =
recently.=20
Kingery and Others produced a book which I regard as being the primer =
for anyone interested in Ceramic Science, "Introduction to Ceramics" =
ISBN 0-471-47860-1. This has chapters about the processes materials pass =
through as they heat up and cool down and about the structures of =
solids, including glasses.
Paul Rado, "An introduction to the Technology of Pottery", 2nd ed, =
explains Seger's concept of molecular formulae and is one of the better =
recent texts though sadly it is now out of print.
Of the older texts Singer and Singer, "Industrial Ceramics" is well =
worth the effort of finding and I like Brownell, "Structural Clay =
Products" ISBN 3-211-81382-9 because he has differing views to those =
found in popular books for Studio Potters.
In all of these, you will find some of the information, as text, tables =
and illustrations, you are seeking when you say "I guess my uncertainty =
stems from; lack of data and imperfect observation. I don't know enough =
to dispute. The scientific minds always want to uncover the truth.>>
Much of the math is derived from observation of events and recording =
data revealed by experimentation, in the way that Ron Roy uses his =
Dilatometer to ascertain rates of linear expansion.
Equations are abstractions representing rules which govern relationships =
between differing quantifiable events or qualities such as Length with =
Temperature, as in the above example, or masses of competing compounds =
and temperature, as in the case of the Unity Molecular Formula (UMF) =
where one of the groups of compounds is considered constant but both =
ratio between, as well as total masses of the other two groups, are =
varied in a variety of ways.
I hope this information helps you in some way or other.
Best regards,
Ivor Lewis. Redhill, South Australia.
One place to start might be to construct models using geometric solids =
which are easy to make. Tetrahedra make good models of Silicate Ions and =
Octahedra work well for Alumina Ions. Bean bag balls can be used for =
Hydroxyls and if you paint them with acrylic paint small ones can be =
used for Alkali Earth Element atoms and big ones can be used for Alkali =
Metal Element Atoms. Pictures to guide you are in the books I suggest.=20
Louis Katz on fri 17 oct 03
We currently look at glazes using unity formulas. These contrast
numbers of molecules; i.e. How many sodium oxide molecules for each
silicon dioxide molecules.
The trouble is that these oxides don't really exist in glazes. Glazes
are a bit more mixed up, the oxygens and metals exist, but they are not
linked together in discrete, seperate, units like molecules are. The
metals share oxygens. The glaze is more accurately one big molecule
than a bunch of individual ones.
The original post postulated that it might be more beneficial at least
in some way to compare numbers of atoms and perhaps ions (an atom that
is short an electron for whatever reason) than oxides.
I don't thinks so, but my knowlege is limited. It is a shame that Carl
Platt is not around to give his opinion on this. He knew a whole lot
but kept getting emboiled in politics on the forum.
Louis
Catherine White on fri 17 oct 03
Thanks for the Oliver Sacks, "My Uncle Tungsten", book suggestion. I found
it for only $6.42 + s&h used. At present I successfully struggle on with
Glaze Calculation and this will no doubt help.
Way-back-when, I was a freshman eagerly starting "real" science classes. The
third day, Mr. Deller was struggling with a jar lid. I said it was a job for
Superman.
Angrily, he replied, "I see we have a wit in the class...... a
half-wit."
Unfortunately, I thought this was fun repartee and replied, " And if we
put our heads together, we'll have a whole wit."
For this I was expelled from his course, the only one in our small town.
Couldn't happen nowadays, I know. This put a major hole in my education as
far as chemistry goes.
And therein, lies the reason I now stuggle with Glaze Calculation!
Catherine in Yuma, AZ
----- Original Message -----
> > There is a wonderful book by Oliver Sacks called "My Uncle Tungsten"
> > (memories of a chemical boyhood.)
> >
> > Anyone will find this book interesting - and if you are not more
> interested in chemistry at the end of it - I for one will be amazed.
> > RR
Ron Roy on sat 18 oct 03
Hi May,
Don't be put off by those who make this all seem more complicated than it
is. I should say it is complicated on a molecular level I suppose but -
getting into the finer points is simply not necessary to get results from
calculation.
You might even say that having a chemistry point of view can be a
hinderance - I certainly don't and I use calculation every day to solve
clay and glaze problems.
If you use calculation to change a glaze - say by adding silica to cure
crazing - and you test the glaze - you can see the results - either the
crazing stops or gets less - the glaze still melts or not, or the colour
and surface is affected or not.
In many ways it's like cooking - the bread rises too much so we increase
the salt or cut down the yeast - the books tell us what to do. We bake
another loaf to see if we made to much of a change or too little.
Books like the Hamer Dictionary give us the clues we need to make logical
choices, calculation counts the combined molecules of the materials so we
know how much we are increasing or decreasing.
Of late there has been a lot of comments on the chemistry - I think most of
that is just over complicating the issue - and some potters are being
intimidated.
I am living proof - I knowing very little chemistry - it is not necessary
to work on clays and glazes. Besides - when it is necessary - it is not
hard to find when you need it.
When I started up with calculation I only knew what I could remember from
high school chemistry - H2O was about it - H has a molecular weight of 1 -
oxygen 16 - so a molecule of water has a molecular weight of 16 + 2 = 18.
All I need is a list of molecular weights to find the molecular weights of
all the oxides we use - but I don't even need that - the calculation
programs do it. Besides - the only use I have for molecular weight is to
make a rough comparison when I I am trying to duplicate a glaze with other
materials and I want to try and get real close.
I will be happy to test my skills with anyone - as a way of proving that a
detailed knowledge of chemistry is not needed to adjust and invent new
glazes and clay bodies. If it were - I would not be able to do what I do.
What is necessary is a willingness to learn, a curiosity about how things
work and the time and energy to do it.
Not for every one I suppose - but I warn you all now - once you start - you
may find you can't stop and you will find it one of the most fascinating
journeys you have ever taken.
RR
>If you and others would not mind, can you help me understand the thread
>better.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Earl Krueger on sun 19 oct 03
To the Clayart community;
It has been brought to my attention that Clayart,
being geared to the practicing studio potter,
may be the wrong forum for discussing this
issue and that more harm than good may have
resulted. Therefore, I am dropping this thread
and will pursue my interest via other means.
My intent was not to confuse or intimidate people,
or to challenge authority, but to explore alternatives.
If I have confused, intimidated or discouraged
anyone from calculating glaze formulas I am
sorry and apologize for that.
I do believe that using the current method to
calculate a glaze formula is a powerful tool
and that the software available greatly simplifies
the task. I encourage everyone who wants to
make adjustments to a glaze to give it a try.
Earl...
Bothell, WA
Ron Roy on mon 20 oct 03
Dear Catherine,
Thank you for posting this.
I don't think it is because you got no chemistry - but if you think that is
the reason you find it seem more difficult - that will certainly make it
seem so.
In the end what is infinitely more important is knowing were to get the
oxides you need and what each of them do in a glaze.
You already have a good start on the analyses of materials in out book and
Hamer will tell you about the function of the oxides in a glaze.
And I am here to answer questions.
RR
>Thanks for the Oliver Sacks, "My Uncle Tungsten", book suggestion. I found
>it for only $6.42 + s&h used. At present I successfully struggle on with
>Glaze Calculation and this will no doubt help.
>
>Way-back-when, I was a freshman eagerly starting "real" science classes. The
>third day, Mr. Deller was struggling with a jar lid. I said it was a job for
>Superman.
> Angrily, he replied, "I see we have a wit in the class...... a
>half-wit."
> Unfortunately, I thought this was fun repartee and replied, " And if we
>put our heads together, we'll have a whole wit."
>For this I was expelled from his course, the only one in our small town.
>Couldn't happen nowadays, I know. This put a major hole in my education as
>far as chemistry goes.
>And therein, lies the reason I now stuggle with Glaze Calculation!
>
>Catherine in Yuma, AZ
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Snail Scott on mon 20 oct 03
At 08:40 AM 10/20/03 +0000, you wrote:
>Thanks for sharing the "big read" list again.
One of my favorite glaze-tech books is Yvonne
Hutchison Cuff's 'Ceramic Technology for Potters
and Sculptors. It's an inexpensive paperback
structured as a textbook, with 'basic' and
'advanced' sections in each chapter. It's
easy to follow, with clear explanations and
relevant information. It also discusses clays
in a similar fashion. Not an in-depth scientific
reference, but a technical course directed at
non-technical people.
Cuff, Yvonne Hutchinson
Ceramic Technology for Potters and Sculptors
University of Pennsylvania Press, 1996
(published jointly in the UK by A&C Black)
ISBN: 0-8122-3071-X (cloth)
0-8122-1377-7 (paper)
-Snail
May Luk on mon 20 oct 03
Dear Ivor;
Indeed, I'm quite new to the list, as well as pottery. I do have a keen
interest in exploring ideas in science. I belong to a science adult learner
group where we sit around and talk about ideas in science with the help of a
professor.
As I received your list, I was excited and disappointed at the same time;
excited for new leads to more knowledge; disappointed that they are books
that are quite costly and difficult to find. It appears that they are books
for material science. I think even if I found it in the library, it would be
in the reference section only. Just for curiosity, I typed in "ion, oxide,
ceramics" in google. I found an research paper in Nature that might be
interesting. But it cost $18 to review it on line. So, no dice for me.
I did buy a practical geology book for 50 pence at the market. It gave me
some diagrams to look at. It would not help me with my glaze. Interesting to
look at, nevertheless.
I ran into John and Ron article in ceramic monthly and they said: "Most
people interested in ceramic science have moved on from pottery and glazes
to applications involving space, electronics and medicine" I assume part of
it is probably because the funding and resources are at the industry level.
Ceramic students, with college tuition and the final income level on their
mind, probably cannot put too much focus on science eventhough they are
interested in it. Of course, there's the "fun" level they have to consider
as well.
Thanks for sharing the "big read" list again.
Best Regards
May
May Luk on mon 20 oct 03
Hi Ron;
Thanks for the kind words and the encouragement.
Some people cook with meat thermometer; some people cook like the "America
Test Kitchen"; some people cook and gone off and work for the lab at
Macdonalds. J
With this thread, I went on and re-read Bailey's book [for the 8th times],
as well as the appendix of your book regarding Unity Formula. The numbers
can be off putting at first. The more I read and talk about it, the more I
understand.=20
Speaking of reading and books;
I just got your book 3 weeks ago. My studio colleague was reading it, and
she wouldn't put it down!. My friend, who bought it for me from the state,
is going to get her own copy. Another potter student friend, who's going to
NY next month, will be getting it as well. I hope this will start a positiv=
e
trend here, as durable glaze is not taught in school. The glaze technology
class in one 2 year certificate programme (community college) here only las=
t
one day.=20
My first class in ceramic a year and a half ago. I asked another tutor, why
my transparent glaze is crazed. He answer that [this] transparent glaze
always crazed. A few months after that, I asked him if he can show me glaze
chemistry. He said it went over his head from his college years. He
graduated with Honours.
I did some currie grid some months ago. Not knowing how to read the result,
I showed them to my tutor. I asked him how do I know if which one is durabl=
e
and food safe; I got a blank look. Granted, he only does garden ware. I was
asking too much. Luckily, I know how to do that now with the practical step=
s
in "Mastering Cone 6"
I went to Chelsea Craft Fair, a leading contempory craft show here in
london, yesterday. I found 4 booths that sells crazed glaze for tableware.
And they don't mean to be crackled. The mugs sell for =A320-30!
Enough of the rants. From my circle of friends and our own "pot talks", som=
e
pottery students are aware of glaze quality. We heard, here and there, abou=
t
lemon slice, leaching, metal release, but nobody has a unified clear
picture; the informations in books are dispersed; the tutors have limited
knowledge- everything comes from the top. Your book really helps to addres=
s
these issues in a practical and simple manner. A big compliment!!
Thanks for the "preach" again
Best Regards
May
John Hesselberth on mon 20 oct 03
On Monday, October 20, 2003, at 05:41 AM, May Luk wrote:
> I did some currie grid some months ago. Not knowing how to read the=20
> result,
> I showed them to my tutor. I asked him how do I know if which one is=20=
> durable
> and food safe; I got a blank look. Granted, he only does garden ware
Hi May,
I can't resist jumping in here. This has troubled me too and I have had=20=
an ongoing discussion with Ian Currie about it. I have now developed a=20=
way to visually portray where the likely areas of stable and unstable=20
glazes are on a Currie grid (also for other blends--line, triaxial or=20
non-Currie quadraxial). It will be incorporated into the 1st upgrade of=20=
GlazeMaster (a free upgrade, if downloaded) which is due for release in=20=
March of next year (=DF testing in January). I am very excited about it=20=
because it turns the numbers into a red/green visual display. And one=20
that you can easily customize as you learn more about your particular=20
needs.
Regards, John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Tony Hansen on tue 21 oct 03
I agree with this.
I too have no chemistry or computer training and I wrote
INSIGHT, the Digitalfire website and now am working on the
ceramic-materials.info website.
The value of calculation is that you understand why things
are happening. One customer we have a couple of years ago
said to me on the phone after a period of frustration:
\"I am ready to understand why glazes do what they do\".
Chemistry is a big and necessary piece of that puzzle.
-------8<--------
Of late there has been a lot of comments on the chemistry - I think most of
that is just over complicating the issue - and some potters are being
intimidated.
I am living proof - I knowing very little chemistry - it is not necessary
to work on clays and glazes. Besides - when it is necessary - it is not
hard to find when you need it.
When I started up with calculation I only knew what I could remember from
high school chemistry - H2O was about it - H has a molecular weight of 1 -
oxygen 16 - so a molecule of water has a molecular weight of 16 + 2 = 18.
All I need is a list of molecular weights to find the molecular weights of
all the oxides we use - but I don\'t even need that - the calculation
programs do it. Besides - the only use I have for molecular weight is to
make a rough comparison when I I am trying to duplicate a glaze with other
materials and I want to try and get real close.
Tony Hansen, Digitalfire
Louis Katz on wed 22 oct 03
The chemistry that is helpful for the level of complexity we normally
handle in glaze calc. is small.I give my students a review of chemistry
as part of a lead up to glaze calculation which we touch upon. My notes
can be had at:
http://www.tamucc.edu/~lkatz/materials/glaze/chemistry_review.html
They aren't pretty, just notes to myself.
I also have a simplified periodic table for my students. It has
elements color coded by group.
http://www.tamucc.edu/~lkatz/materials/glaze/periodic_table.html
Los Almos has a more complete one:
http://pearl1.lanl.gov/periodic/default.htm
There are lots of other resources on the web.
The chemistry concepts used in glaze calculation are covered in good
junior high science classes, and any high school chemistry class
handles them in the first part of the year.
iandol on wed 22 oct 03
Dear Earl Krueger,=20
A sad day yesterday. I read your post justifying your withdrawal from =
discussions about the chemistry of clays and glazes. I hope we can =
continue correspondence in private relating to this particular topic.
As I said, presenting this viewpoint into the public arena was a =
brilliant idea. It is important to know we are exploiting Ions rather =
than Molecular Oxides. I agree, it is not an easy topic to come to terms =
with. I agree, Seger Formulations and Glaze Calculation Programs which =
support the solution of glazing problems, presented in that convention, =
may be the best available tools for people to use.
Critics of the application of Chemical Science in the field of Studio =
Ceramics should always remain conscious of the fact that Clays, Spars =
and other Chemicals, though represented in an abstract sense using the =
Molecular Oxide Convention of Herman Seger are also thought of as being =
excited atoms held in place by electron forces. The rules which govern =
this interplay are what we need to use to solve other non numerical =
problems.
Hoping that you continue to make a contribution to Clayart.
Best regards,
Ivor Lewis. Redhill, South Australia=20
iandol on wed 22 oct 03
Dear Snail Scott,=20
Hutchinson Cuff's text is a great collection of lesson plans for anyone =
who may be called upon to teach a course at short notice.
But there are inconsistencies and some glaring errors which should be =
sorted out before it is reprinted.
Best regards,
Ivor Lewis. Redhill, South Australia
Ron Roy on wed 22 oct 03
Hi May,
Thanks for this post - I do feel like a preacher sometimes - and it is
wonderful when the reaction is like yours. It is easy to get discouraged
with all the confusion in this subject but it is so important we just have
to keep trying.
Some one said it will take more than a few books to fix this up - perhaps -
but it is a start and it is about time. I think we would all be very
surprised at just how many potters have learned to use glaze calculation
software over the last 5 years.
Wouldn't it be wonderful if all published glazes had the Seger formula with
them - and some intelligent comments to help explain what it means - in
words potters would easily understand.
Like Ababi does.
We will do it here and it will spread - as Mel says - it's grass roots and
it will spread - can't stop it! What we need now is the jumping in part.
Who knows - maybe teachers will someday be required to know it and teach
it. It is so much easier now - there is no reason to not know it.
RR
>Thanks for the kind words and the encouragement.
>
>Some people cook with meat thermometer; some people cook like the "America
>Test Kitchen"; some people cook and gone off and work for the lab at
>Macdonalds. J
>
>With this thread, I went on and re-read Bailey's book [for the 8th times],
>as well as the appendix of your book regarding Unity Formula. The numbers
>can be off putting at first. The more I read and talk about it, the more I
>understand.
>
>Speaking of reading and books;
>
>I just got your book 3 weeks ago. My studio colleague was reading it, and
>she wouldn't put it down!. My friend, who bought it for me from the state,
>is going to get her own copy. Another potter student friend, who's going to
>NY next month, will be getting it as well. I hope this will start a positive
>trend here, as durable glaze is not taught in school. The glaze technology
>class in one 2 year certificate programme (community college) here only last
>one day.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Louis Katz on thu 23 oct 03
I have been on this forum and off for quite a long time with what
really amounts to a short break. Many things have changed. There have
been times when it seemed no one was interested in talking about
glazes. The kind of interest in glazes has changed. Several things have
happened that seem to be the reasons for shift.
1. Dave Shaner's untimely death. He will be missed by all who knew him.
Those that did not know him continue to be affected by his influence on
clay and sculpture. He also believed that he was poisoned by manganese.
It is doubtful that we will ever know if this was true or not but his
illness created a palpable move towards more care with certain
chemicals.
2. Ron Roy's steadily increasing knowledge and his unrelenting
generosity on this forum. It is not like he was born knowing about
glazes. He has been teaching himself over the last decade or so.
3. John and Hesslebreth and Ron Roy's book along with Johns generosity
on clayart.
4. Digital Fire and Tony Hansen and their generosity. What a great
resource the website is. http://www.digitalfire.com/material/index.htm
5. Richard Burkett, a founder of clayart who is no longer on the forum.
Early on he was always ready with an answer.
Ivor has been on always ready to challenge assumptions, and help us to
understand the limits of our understanding. Countless untold others no?
------------------------
Louis
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