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designing glazes. the distincion between discovery and exploitation

updated tue 3 jun 03

 

iandol on tue 27 may 03


Dear Tony Hansen,

Nothing wrong with your approach as a way of obtaining some sort of =
useful glaze from your chosen new material. But it is one which is =
constrained by the limitations of what has been seen to be "Good =
Practice" or "Typical Practical Limits".

Designing means that you start with a series of ideas you wish to =
achieve based on your own experiences, whatever their source, for =
inspiration. These you translate into images which can be analysed for =
all of the elements of design, Shape, Form, Colour (Hue, Tone, =
Intensity), Texture and so on.

Since we are dealing with the surface when we consider using a glaze, =
start with the thing which is most important in the glaze, the Major =
Melting Agent. Then select from other ingredients according to their =
potential to achieve the qualities which you have defined in your =
creative activity plan. Now feel free to engage the services of your =
computer, or pen and paper if you wish. Alternatively, carry out a =
series of line and other sample blend frame works and have a good look =
at what is possible in a practical experiment.

In one way Lili is correct, suggesting that all the glazes have been =
invented and recorded. It may take time to test my assertion, but =
something like 80% of cone 8 and over Stoneware and Porcelain glazes =
have their roots in B. Leach's Standard Cone 8 Limestone Glaze, 4-3-2-1 =
(P.172 in the table of Pale or colourless Glazes). Glazes which fit into =
the lower cone bracket for middle fire are the same, modified with a =
Boron Melting agent or the substitution of Neph. Sy. for Potash Fels =
though I would imagine the work of Ron and John would fall outside the =
scope of this generalisation.

I think we should remember that Design implies Intentions and not =
Exploration and Discovery. What you suggest, the Analysis and =
Incorporation of New Materials into an ongoing Research and Development =
Program takes place prior to the process I describe.

John Hesselberth on wed 28 may 03


Hi Tony, Ivor;

On Tuesday, May 27, 2003, at 03:30 AM, iandol wrote:

> Nothing wrong with your approach as a way of obtaining some sort of
> useful glaze from your chosen new material. But it is one which is
> constrained by the limitations of what has been seen to be "Good
> Practice" or "Typical Practical Limits".

Very true. I regard limits as a good place for inexperienced potters to
start their glaze formulation journey. Then explore outside limits as
you gain experience.

Setting limits for silica and alumina does seem to have validity if you
want to make durable glazes (although some of the published sets are
terrible when this criteria is used, e.g. the Zakin/Schmitz cone 3-5,
cone 09-04 and even some of the cone 8-10 limits in "Ceramics:
Mastering the Craft" will almost certainly give non-durable glazes--and
there are others--I don't mean to single out Zakin's book--I only used
it to exemplify).

But many of the "interesting" glazes occur outside of the so-called
flux limits--and they can be very stable for functional work. I
haven't added it up, but I would guess most of the glazes in Ron's and
my book are outside traditional "limits" -- depends on exactly whose
you use, of course. But, in particular, we ignore calcium and boron
"limits".

Regards,

John


http://www.frogpondpottery.com
http://www.masteringglazes.com

Wes Rolley on wed 28 may 03


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At 09:41 AM 5/28/03 -0400, you wrote:

>I regard limits as a good place for inexperienced potters to
>start their glaze formulation journey. Then explore outside limits as
>you gain experience.

Most of the commentary from recognized experts (Ivor, Tony and you, John)=20
talk about a road of exploration and discovery. My original question was=20
addressed to a different point.

I have an image of a glaze in mind. I can see all of it's surface=20
characteristics, etc. I used a specific glaze as an example...one that I=20
happen to like but have not been able to duplicate in an electric=20
firing. But the questions is much more general.

I want to design a glaze to meet those specific characteristics and what I=
=20
am hearing from the experts is "don't do that." What I am hearing is to go=
=20
explore the materials, see what they give and work with that. I can do=20
that for the rest of my life and may never get around to designing the=20
glaze I can see in my mind.

I guess that this thread is a dead end I need to go back to figuring it out=
=20
piece by piece.... there might even be a book, or at least an=20
article, well maybe a post to Clayart sometime in the future.

Wes

"I find I have a great lot to learn =96 or unlearn. I seem to know far too=
=20
much and this knowledge obscures the really significant facts, but I am=20
getting on." -- Charles Rennie Mackintosh

Wesley C. Rolley
17211 Quail Court
Morgan Hill, CA 95037
wrolley@charter.net
(408)778-3024

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Rick Hamelin on wed 28 may 03


Well, then it is back to the books. Magazines. And here. Many books in my
library of 27 years have photographic examples accompanying the recipes. This
sounds like a starting point. Ceramics Monthly has had pots and recipes as
well. Either way, it takes some digging. Research. Either way, it is not a
direct line or quick answer.
Good luck
> At 09:41 AM 5/28/03 -0400, you wrote:
>
> >I regard limits as a good place for inexperienced potters to
> >start their glaze formulation journey. Then explore outside limits as
> >you gain experience.
>
> Most of the commentary from recognized experts (Ivor, Tony and you, John)
> talk about a road of exploration and discovery. My original question was
> addressed to a different point.
>
> I have an image of a glaze in mind. I can see all of it's surface
> characteristics, etc. I used a specific glaze as an example...one that I
> happen to like but have not been able to duplicate in an electric
> firing. But the questions is much more general.
>
> I want to design a glaze to meet those specific characteristics and what I
> am hearing from the experts is "don't do that." What I am hearing is to go
> explore the materials, see what they give and work with that. I can do
> that for the rest of my life and may never get around to designing the
> glaze I can see in my mind.
>

> I guess that this thread is a dead end I need to go back to figuring it out
> piece by piece.... there might even be a book, or at least an
> article, well maybe a post to Clayart sometime in the future.
>
> Wes
>
> "I find I have a great lot to learn or unlearn. I seem to know far too
> much and this knowledge obscures the really significant facts, but I am
> getting on." -- Charles Rennie Mackintosh
>
> Wesley C. Rolley
> 17211 Quail Court
> Morgan Hill, CA 95037
> wrolley@charter.net
> (408)778-3024
>

John Hesselberth on wed 28 may 03


On Wednesday, May 28, 2003, at 12:30 PM, Wes Rolley wrote:

> What I am hearing is to go explore the materials, see what they give
> and work with that. I can do that for the rest of my life and may
> never get around to designing the glaze I can see in my mind.

Hi Wes,

You are not hearing that from me. I start with a description or mental
image of the glaze I want. Then I postulate a composition (Seger
formula) that will give that. I do that by lots of reading and bringing
to bear a fair amount of experience. Then I design a glaze recipe
having that formula using calculation software. When I get someplace in
the ball park, I will do line blends around that composition to zero in.

Admittedly I try other techniques at times. Waterfall was discovered
because I wanted to see what I got when I jammed boron up against the
ceiling. But generally I approach it per the above.

I think each person has to develop their own strategy. There is no
right or wrong way, although I am a strong believer in using
calculation as a tool--as long as you don't stay in "limits" too often.
It can really confine you if you do. I think that is why some people
talk down calculation.

Regards,

John
http://www.frogpondpottery.com
http://www.masteringglazes.com

iandol on thu 29 may 03


Dear Wes,

You read me incorrectly. You have described your intentions in fairly =
explicit terms except for the nature of the colour. You know the =
conditions under which you will fire. From your appraisal of the =
situation you cannot achieve your intentions in the same way that your =
Model was made. So you seek alternatives.

Taking your three prime ingredients I would add a fourth. Include =
Silica. You then need to prepare three 6*6 test tiles each 150 mm =
square. These will allow you to cover the high, middle and low ranges of =
the main melting ingredient, your Potash Felspar ( I can send you the =
Matrices via e-mail if you wish to proceed this way). Preparing these =
takes about nine hours. When they have been fired in your kiln under the =
conditions available to you you will be able to select at least one and =
possibly several samples which give the optical and tactile qualities =
you seek. Now you need an objective assessment of the colour because I =
am not going to impose Rx firing. But I can lead you towards the colour =
you seek.

Best regards,

Ivor

Paulette Carr on mon 2 jun 03


Good morning, Ivor!

I read your recent post/response to Wes and Stephani with interest. I am not
familiar with this matrix ("common or garden 6*6), though I am familiar with
the one that Ian Currie uses (7 x 5). Could you explain it, and send it to
me? I am continuing my ever-ongoing process of developing glazes, and have even
brought myself up to speed with glaze calculation. I thought I should know
something about your approach. What are the high, medium and low ranges for a
primary melting agent, and for that matter how do I decide which is the
primary melting agent when I have a mixture of flux oxides?... Can you, also,
please suggest a literature source(s) to me?

Many thanks, and best regards,
Paulette Carr
St. Louis, Missouri

<From: iandol
Subject: Re: Designing Glazes. The distincion between Discovery and
Exploitation

Dear Wes,

You read me incorrectly. You have described your intentions in fairly =
explicit terms except for the nature of the colour. You know the =
conditions under which you will fire. From your appraisal of the =
situation you cannot achieve your intentions in the same way that your =
Model was made. So you seek alternatives.

Taking your three prime ingredients I would add a fourth. Include =
Silica. You then need to prepare three 6*6 test tiles each 150 mm =
square. These will allow you to cover the high, middle and low ranges of =
the main melting ingredient, your Potash Felspar ( I can send you the =
Matrices via e-mail if you wish to proceed this way). Preparing these =
takes about nine hours. When they have been fired in your kiln under the =
conditions available to you you will be able to select at least one and =
possibly several samples which give the optical and tactile qualities =
you seek. Now you need an objective assessment of the colour because I =
am not going to impose Rx firing. But I can lead you towards the colour =
you seek.

Date: Thu, 29 May 2003 16:45:33 +0930
From: iandol
Subject: Re: designing a glaze

Dear Stephani Stephenson,

Good summation of the trials, torments and tribulations of the Wild =
Glaze Explorer.

Ah, the Quadraxial Blend Matrix, be it 7*5 or 6*6. Not sure about the =
7*5 but the common or garden 6*6 only gives you one third of the =
possibilities! And if you go through the High, Medium and Low ranges for =
your primary melting agent you increase the factions by a factor of =
three again.

Best regards,

Ivor>>