lili krakowski on tue 17 feb 04
This is sort of off track BUT:
When glaze is applied in layers, especially of different glazes, many =
factors enter into play. The body underneath, the speed and speed rise =
of firing, the atmosphere, the cooling rate, the composition of each =
glaze, the relative thickness of the coats, the method of application. =
Which of the two glazes goes on first. Therefore testing and =
experimenting is essential, and while ALL the answers from our generous =
glaze experts are on target, right on, and like that, you still have to =
test and check, and try to control your own situation.
Having said that: To get back to my basic analogy. When a recipe calls =
for wine, people who do not use alcohol use a bit of vinegar. And if =
that is not to be had then lemon juice, lime juice, tamarind, and a =
variety of other mild, edible, acids can be used. I expect that in a =
simple test such as litmus paper, the acidity could be checked and yes, =
the acidity called for by a 1/4 c. of Merlot can be matched by a dab of =
tamarind paste. But the result is not the same. Obviously. You knew =
that.
Much the same applies to clay and glaze and that is why while I would do =
anything for Hermann Seger, he deserves a huge statue and all that, =
there are clear limits to molecular formulae.
Of course a formula can be matched. One way or 'tother. But as has =
been said endlessly in classrooms and on Clayart, there are so many =
variables that a formula --when translated into a reciope --remains =
close to a ballpark guess. Mined products change. Some materials are =
mined in diverse parts of the world and if your supplier changes from =
source A to source B there may, probably will, be variations. Just now =
I checked some sources of whiting--and no, the different "whitings" sold =
were NOT identical in composition. =20
I could go on an on. But from many points of view--well, mine anyway-- =
it is wise to consider glazes as within families, just as we consider =
cooking recipes within families. There are chocolate cakes, and breads, =
pies, roasts, soups----and one really owes oneself to try several =
recipes within the family before latching on to The One. Leaving aside =
basic characteristics--low fired, medium, high, reduction, =
oxidation/neutral-- and basic appearance--shiny, matt,etc--there is a =
large family of alkaline glazes, alkalines and earth, calcium borates, =
zinc containing, and a few more I no doubt forgot. It remains best, I =
think to "have"several of each family in one's recipe file and test =
them, and keep the resulting tiles together. So when you cannot find GB =
anymore, you are right there with a frit using recipe so similar its =
mother would not know....
Hence: while I definitely feel--and have taught--that all potters =
should be able to do, or have GlazeMaster (TM) to do molecular =
formulae--there still is need for easy flexibility when it comes to the =
nitty-gritty recipe. And that comes from testing, and getting the feel =
of it all.
Lili Krakowski
Be of good courage
Lee Love on wed 18 feb 04
lili krakowski wrote:
>
>Hence: while I definitely feel--and have taught--that all potters should be able to do, or have GlazeMaster (TM) to do molecular formulae--there still is need for easy flexibility when it comes to the nitty-gritty recipe. And that comes from testing, and getting the feel of it all.
>
>
Lili, I agree with the greater part of your post.
But I don't believe that every potter needs GlazeMaster. If one is
dependent upon glaze calculations, one is forced to limit oneself to
industrial, refined, purified, DEAD materials. There are other
approaches to glazes, ones that are far more dependent upon testing.
When you are using natural, unrefined materials, you can never be sure
of the analysis. So you have to do more testing.
The method dependent upon analysis is good at control and
reproducible results. Traditional methods that use natural,
non-industrial materials allow for more variation and discovery.
Our work is highly dependent upon the way we choose to
approach the work in the beginning. The traditional method is
flexible and is not dependent upon industrial materials, but allows for
their use. The only drawback is that they require more testing.
Lee In Mashiko, Japan.
Hendrix, Taylor J. on wed 18 feb 04
Lee,
More testing is not the only draw back to more traditional methods; I'm
beginning to understand. Not only do you have to be more deliberate in
your testing of 'unknown' material, you also have to locate, collect,
and process that material. That can be quite a burden of time,
equipment, and other resources. Man, I have some shale, limestone, and
dirt from the local area and just those three things have doubled or
even trebbled my prep time for tests. The hardest of the trinity,
limestone, I can powder with my 12 oz claw hammer. Just wait till I
start collecting the hard minerals and rocks. THAT is going to take
some time and energy for sure. Perhaps it's not to early to start
thinking about getting me some indentured servants. Hehe
Taylor, in Waco
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Lee Love
Sent: Wednesday, February 18, 2004 8:33 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Glaze thoughts/ cooking thoughts/ layers/moleculars/ s rant
...
Our work is highly dependent upon the way we choose to
approach the work in the beginning. The traditional method is
flexible and is not dependent upon industrial materials, but allows for
their use. The only drawback is that they require more testing.
Lee In Mashiko, Japan.
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Lee Love on thu 19 feb 04
On 2004/02/19 9:23:49, clayart@lsv.ceramics.org wrote:
> More testing is not the only draw back to more traditional methods;
> I'm beginning to understand. Not only do you have to be more
deliberate in
> your testing of 'unknown' material, you also have to locate, collect,
> and process that material. That can be quite a burden of time,
Taylor, I think we are mixing up two different things and I
believe it is keeping potters hobbled to the industrial paradigm back home.
Here in Japan all the materials required for the "traditional
method" are available at the local clay co-operative. And at another
local clay store, you can get these same types of materials (in addition
to industrially refined materials) from all over Japan.
I don't dig up my Mashiko or Shigaraki clay. Mashiko comes
from the Co-op and Shigaraki is imported from its local by a local
company. The clay is processed in such a way that the variations that
are so important in the work, (which are not acceptable by industry),
are retained within the material. It has been pugged and everything,
I just have to take if out of the plastic bag and wedge it, just like
back home.
The same is true of all other necessary materials. I have
bags of kaolin, ball clay, feldspar, kaki, various types powdered stone,
and you can even buy several kinds of washed ashes if you so desire.
You can even buy traditional glazes all mixed up for you, but you have
to bring your own bucket. You should see the huge blundgning tanks
that hold Nami Jiro, Nuka, Kuro and Ame glazes! You should see how
small the woodcutters split the red pine for you, but of course, you
have to pay for their time. :^)
Why is this possible here in Japan? Because the potters know
the difference between these materials that are specifically prepared
for potters and materials prepared for industry and demand the materials
specifically prepared for potters.
If folks back home knew the difference, and created a demand for
the product, I think we could have more potter specific materials too.
Lee In Mashiko, Japan
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