iandol on sun 1 oct 00
Dear Ababi,
Thank you for your response. I appreciate what you are saying. Yes, I =
can access a glaze calculation program. Yes, I know what to do and do =
use it sometimes to check my own spreadsheet calculations. I am aware =
that things can be swapped around in a glaze recipe without doing any =
great damage so that a new surface or texture or colour is made =
available. And yes, I think it is a good idea to dump glazes which have =
outlived their useful life in a person=92s aesthetic development.
But it seems to me that there are two ways of taking on glaze =
development. There is the theoretical, where a person follows the =
teaching of this or that lecturer or guru, be that by direct contact as =
in your own case, or by reading or by using a glaze calculation program =
in their computer. Then there is the empirical approach, where you apply =
basic, fundamental or universal knowledge, set too and weigh out =
portions of this and that for line, triaxial or square tile blend tests =
then fire them to see what will happen. Those results are examined and =
modified to meet one=92s own aesthetic pleasures with colour or texture =
or opacifier.
This is what I did. I wished to dump an original tile, based on =
materials that I could obtain, which had provided me with several =
excellent glazes, though some had been modified with GB and Petalite to =
make them fit the clay I use without changing their maturity range or =
colour response. So I dropped Whiting from the equation and constructed =
a tile with Wollastonite and other things. I could not have predicted =
the results. The computer would not have taken account of the clay I =
continue to use or new clays I intend using. Out of thirty six mixtures =
only one crazed, (low Calcia, high Silica, high Soda). I expected many =
more. Pin holing is almost eliminated. They range from fully transparent =
to white opaque, from stiff to quite fluid. The other advantages are the =
elimination of a scarce, almost obsolete commodity and an expensive one
All of which brings me back to my rhetoric, and now causes me to ask, =
"How many people really design a glaze to meet their aesthetic =
requirements" How many people on clayart and elsewhere can describe =
their intentions objectively then, working from first principles, =
construct a test program, select, measure, and mix materials, fire them =
and continue making adjustments until they achieve their aims?
With regard to your information about the frit. My appraisal of this is =
that it is a Sodium/Barium Borosilicate frit suitable for making clear =
transparent earthenware glazes. The high sodium and low calcium suggest =
that it will be physically soft and might be prone to high fluidity at =
higher cone values as well as having a low fusion point, making it a =
dubious selection for underglaze decoration or domestic ware. The =
inclusion of zinc may make it unsuitable for reduction stoneware =
firings. What predictions do you achieve with your computer program?=20
My best regards to you,
Ivor Lewis. Redhill, South Australia
Sharon31 on tue 3 oct 00
Hello Ivor!
Today I talked to my good adviser, Yehuda Koren, Like you, he is many years
in ceramics&teaching and does not need a software, as he does, as he has
said before, "in his head".lucky you!
I do not like the word, I read here sometimes, NOVICE, means for me : I am
new and therefor can make mistakes.We all can make mistake but must learn
from them and more, give a thought of the cause for the failure, not just
'Hi I am a novice!' In the short time that I am in ceramics, I learnt one
thing: To learn as less as possible, means, A LOT! The ceramic software
lets me to develop glazes, change temperature (cone in English) understand
materials and so on,. What so on?every time and everyday I find more answers
in the "strange numbers".
You asked, me what does my program say about this frit?
frit Nr. 169
=============
BaO 0.12* 9.05%
CaO 0.09* 2.30%
Na2O 0.64* 19.17%
ZnO 0.15* 5.87%
Al2O3 0.01 0.31%
B2O3 0.85 28.42%
SiO2 1.21 34.88%
Si:Al 193.33
SiB:Al 329.33
Expan 11.60
Well , to tell you the truth, I do not know exactly, perhaps Tony Hansen,
Ron Roy or Tom Buck could give you a good answer. What I do, in cases like
this, is to compare, with frits that I know 6004, 3134, etc. The expansion,
silica alumina, etc. And see the oxides, that build the frit.
A lovely way to work with barium, a start to nickel glazes will it be blue,
because of the Zinc or yellow because of the barium?
This frit is in the quite north, for me only theoretical, (the frit and the
quietness) so , I hope I answered,
It is possible to test the way you do with a lot of knowledge, or that other
do with less knowledge. using the software allows me to get the required
results faster!
This days I mixed my basic raku glaze it is "my" frit 70, and wollastonite
30.
In one some the tests, I break the wollatonite to whiting and another
material with the right amount of silica like ultrox, in order to get the
same glaze the same structure but very white , I am testing 8 glazes, in the
old way, of the uncalculated person, I would have to make hundreds of tests!
Hoping for better future.
in this part of the globe.
Ababi Sharon
sharon@shoval.org.il
http://www.milkywayceramics.com/cgallery/asharon.htm
----- Original Message -----
From: "iandol"
To:
Sent: Sunday, October 01, 2000 09:28
Subject: Re: An advantageous substitution! and a Frit Appraisal
Dear Ababi,
Thank you for your response. I appreciate what you are saying. Yes, I can
access a glaze calculation program. Yes, I know what to do and do use it
sometimes to check my own spreadsheet calculations. I am aware that things
can be swapped around in a glaze recipe without doing any great damage so
that a new surface or texture or colour is made available. And yes, I think
it is a good idea to dump glazes which have outlived their useful life in a
person's aesthetic development.
But it seems to me that there are two ways of taking on glaze development.
There is the theoretical, where a person follows the teaching of this or
that lecturer or guru, be that by direct contact as in your own case, or by
reading or by using a glaze calculation program in their computer. Then
there is the empirical approach, where you apply basic, fundamental or
universal knowledge, set too and weigh out portions of this and that for
line, triaxial or square tile blend tests then fire them to see what will
happen. Those results are examined and modified to meet one's own aesthetic
pleasures with colour or texture or opacifier.
This is what I did. I wished to dump an original tile, based on materials
that I could obtain, which had provided me with several excellent glazes,
though some had been modified with GB and Petalite to make them fit the clay
I use without changing their maturity range or colour response. So I dropped
Whiting from the equation and constructed a tile with Wollastonite and other
things. I could not have predicted the results. The computer would not have
taken account of the clay I continue to use or new clays I intend using. Out
of thirty six mixtures only one crazed, (low Calcia, high Silica, high
Soda). I expected many more. Pin holing is almost eliminated. They range
from fully transparent to white opaque, from stiff to quite fluid. The other
advantages are the elimination of a scarce, almost obsolete commodity and an
expensive one
All of which brings me back to my rhetoric, and now causes me to ask, "How
many people really design a glaze to meet their aesthetic requirements" How
many people on clayart and elsewhere can describe their intentions
objectively then, working from first principles, construct a test program,
select, measure, and mix materials, fire them and continue making
adjustments until they achieve their aims?
With regard to your information about the frit. My appraisal of this is that
it is a Sodium/Barium Borosilicate frit suitable for making clear
transparent earthenware glazes. The high sodium and low calcium suggest that
it will be physically soft and might be prone to high fluidity at higher
cone values as well as having a low fusion point, making it a dubious
selection for underglaze decoration or domestic ware. The inclusion of zinc
may make it unsuitable for reduction stoneware firings. What predictions do
you achieve with your computer program?
My best regards to you,
Ivor Lewis. Redhill, South Australia
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