Jon Pacini on tue 26 apr 05
-----Original Message-----
From: Jon Pacini [mailto:jpacini@lagunaclay.com]
Sent: Tuesday, April 26, 2005 12:21 PM
To: Ron Roy
Subject: RE: T2 clay & carbon core
Greetings All, Hi Ron----If I'm making a clay for general consumption,
initially I test it under the firing conditions I use for QA testing. But
ultimately I send it out to a bunch of potters I regularly use for
field-testing. They fire under all different types of conditions, so I get
an idea how the body reacts under various situations. I would never rely on
one set of conditions to see if a clay is viable.
But you can't really expect a high iron body, which is intended to be black
in oxidation, do anything but fuse and bloat in reduction. Nor can you
expect a body that is made to be black in reduction be as rich in color or
as vitreous when fired in oxidation.
If I'm making a clay for an individual potter/manufacturer, ultimately they
have to test the clay under their conditions to make sure it works for them.
No matter how well the clay works here in the lab, it's how the clay
performs under the conditions it's going to be used that matters.
The fact of the matter is that you just never know how a box of clay is
going to be used when it's purchased off the shelf. And as a potter, to
purchase an unknown quantity and assume it's going to work to your
expectations is a bit unrealistic. Granted, clays should work within the
parameters laid down by the manufacturer, but under any given firing
conditions it may come out lighter or darker or more vitreous or less. After
all firing conditions vary from potter to potter.
As I said previously I don't think you're being unreasonable, but rather a
bit unrealistic. Everyone doesn't produce ware using the same techniques.
You can't expect a clay to perform in exactly the same manner no matter how
it's used.
Best regards
Jon Pacini
Clay Manager
Laguna Clay Co
-----Original Message-----
From: Ron Roy
Hi Jon,
So if you are formulating a high iron clay body - to be fired in reduction
- under what conditions would you test it. - And if it bloated when fully
reduced - would you sell it like that or make some adjustments - or say -
don't fully reduce this body?
I think it is important that we embrace some sort of standards - as clay
and glaze makers - and take responsibility for the products we make and
sell. Surely it is in the best interests of all potters - to have reliable
information and products. It is difficult enough for potters to deal with
all the technical issues without having to guess about whether a clay will
work properly at the temperature and atmosphere they fire at.
RR
Jon Pacini on tue 10 may 05
-----Original Message-----
From: Jon Pacini [mailto:jpacini@lagunaclay.com]
Sent: Tuesday, May 10, 2005 10:38 AM
To: Ron Roy
Subject: RE: T2 clay & carbon core
Greetings All---Hi Ron ---Are you in some way trying to infer that there is
no testing program or an inferior testing program in place for raw
materials, clays and glazes at Laguna?? I sure hope not.
Let me remind you that we here in the Lab at Laguna regularly use X ray
diffraction to do comparative analysis on raw materials and products. We use
our dilatometer to do COE analysis regularly, and use our gradient furnace
for analysis of materials and products over large temperature ranges. This
is in addition to shrinkage, absorption, deformation and appearance tests
done daily on our production of products. Our QA testing includes firing 5
kilns at various temperatures and atmospheres on a daily basis.
NOBODY, and I mean NOBODY, does more QA work on more products and raw
materials than we do here in the Lab at Laguna.
It is from my experience of over 30 years working with all this equipment,
QAing literally over 100 tons of clay a day, thousands of tons of raw
minerals on a daily basis and seeing the variations in those materials that
I draw my conclusions from.
Your call for standards is indeed rooted in your Idealism. But until all
potters are taught to work in a lock step manner and the mineral mines all
become patrons of the arts, I don't see how your standards are any more than
a pipe dream.
Best regards
Jon Pacini
Clay Manager
Laguna Clay Co.
-----Original Message-----
From: Ron Roy [mailto:ronroy@ca.inter.net]
Sent: Tuesday, May 10, 2005 10:13 AM
To: CLAYART@LSV.CERAMICS.ORG
Cc: jpacini@lagunaclay.com
Subject: Re: T2 clay & carbon core
Hi Jon,
No need to go that route - just institute a program of testing bodies and
raw materials - you can then compensate for variable raw materials.
Not rocket science - but it does take a particular point of view to start
with.
Not a bad idea to test glazes for stability either - then potters would
know which are appropriate for liner glazes.
RR
>A ton of clay or a hundred pounds of glaze might get a bit expensive---but
>hey!!--- I'm sure every potter will appreciate the stability of these
>materials.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on wed 11 may 05
Hi Jon,
I have no idea what testing you are doing - I do remember you saying you
don't have time to test all the batches of clay Laguna makes every day.
Is any of your test data available - and to whom?
I have tested a number of your bodies in my dilatometer for instance - care
to compare my results with yours?
Are the glazes you produce tested for durability - are any rated in any way
as to toxicity.
If you are providing leadership I encourage you to let us all know - what
could be better?
Lock step is one of those phrases designed to demean and humiliate - to
stop communication and hinder understanding.
There are times when it is a good idea to have standards - so we can make
intelligent choices - it does not mean conforming in a way that suppresses
creativity.
RR
I apply standards every day to the clay bodies I monitor - not a pipe dream
at all - the result are clays that hardly ever produce problems for the
potters using them.
>Greetings All---Hi Ron ---Are you in some way trying to infer that there is
>no testing program or an inferior testing program in place for raw
>materials, clays and glazes at Laguna?? I sure hope not.
>
>Let me remind you that we here in the Lab at Laguna regularly use X ray
>diffraction to do comparative analysis on raw materials and products. We use
>our dilatometer to do COE analysis regularly, and use our gradient furnace
>for analysis of materials and products over large temperature ranges. This
>is in addition to shrinkage, absorption, deformation and appearance tests
>done daily on our production of products. Our QA testing includes firing 5
>kilns at various temperatures and atmospheres on a daily basis.
>
>NOBODY, and I mean NOBODY, does more QA work on more products and raw
>materials than we do here in the Lab at Laguna.
>
>It is from my experience of over 30 years working with all this equipment,
>QAing literally over 100 tons of clay a day, thousands of tons of raw
>minerals on a daily basis and seeing the variations in those materials that
>I draw my conclusions from.
>
>Your call for standards is indeed rooted in your Idealism. But until all
>potters are taught to work in a lock step manner and the mineral mines all
>become patrons of the arts, I don't see how your standards are any more than
>a pipe dream.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on fri 13 may 05
Hi Jon,
I don't remember any outline on the testing you do - do you have that out
line on your web site?
I do remember you said you were trying to have the results of your
dilatometer testing up before NCECA but never saw any notice that it was
up. It would be very helpful when I am working on fit problems for some
potters who use your clays.
What do I have to do to see the results of your raw materials testing?
I don't know if I agree with your generalization that dilatometer results
vary a lot from firing to firing - that is so in some cases but my years of
experience some there are remarable similarities - measuring the same clay
over the years - even those which have been adjusted - including those that
have had one clay completely sunbstituted for another.
Another aspect of a "standard" we must use - I use a standard sample (fused
alumina) to calcibrate my dilatometer every 50 or so runs - just another
example of a useful standard.
Pyrometric cones are standards.
I don't understand your king of ClayArt remark - are you suggesting there
are those on this list that use ClayArt for other than altuistic reasons?
Are you suggesting that leadership implies a popularity contest of some sort?
RR
>I'm surprised at you Ron, I've outlined the QA procedures we use at Laguna
>many times here on Clayart in threads that both of us have been involved in.
>They are in the archives should you or anyone else care to look them up. The
>results from our testing are on file here and are available to anyone who
>wishes to contact Laguna.
>
>This is common knowledge to anyone who has read my past posts.
>
>Let me refresh your recollection---I've never said I don't have enough time
>to test every batch of clay ---though I have said I don't have time to do a
>dilatometer analysis on every ton of the over 100 tons of clay we produce
>daily.
>
>As for comparing dilatometer readings, seeing your results don't really make
>much difference to me one way or the other. I have looked at results from
>various firing procedures and as I'm sure you know, changes in firing
>procedures affect the physical COE's of clays. Not sure what the point of
>that would be.
>
>Concerning leadership, I'm not interested in being the King of Clayart or
>leading anyone anywhere. There is room enough in Ceramics for everybody as
>far as I'm concerned. Not just the potters who do things "properly"
>according to some "standard", I don't belong to that religion. Heck, I even
>like the ram press and jigger guys, though the slip cast people are a little
>edgy-- :).
>
>Oh and by the way ----I'm glad for you that your clays hardly give anyone
>any trouble. Frankly, neither do the ones that I have developed, which is
>why Laguna produces so much of them.
>
>And in closing -I haven't seen any comment from you concerning Jonathan
>Kaplan's last post on this thread---did I miss it or are you just ignoring
>him? He's so much more eloquent than I am, don't you think?
>
>Best regards
>Jon Pacini
>Clay Manager
>Laguna Clay Co.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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