Craig Martell on fri 23 jun 00
>X-From_: fcurriap@flexi.net.au Sat Jun 24 03:12:26 2000
>Delivered-To: ashglaze@teleport.com
>From: "Ian Currie"
>To: "Craig Martell"
>Cc: "Hank Murrow"
>Subject: Re: Stoneware Glazes. The Ian Currie Plan
>Date: Sat, 24 Jun 2000 13:16:51 -0400
>X-Mailer: Microsoft Outlook Express 4.72.3110.1
Hello mel, Ivor, and Clayart:
I've been in touch with Ian Currie and I forwarded Ivor's questions to him
so that he could possibly post a response to Ivor and Clayart. Who better
to answer the question? He has sent me his response and asked me to post
it to Clayart for him.
Craig Martell in Oregon
----------------------------------------------------------------------------
---------------------------------------------------------------
> >From Ivor Lewis:
> >However, there is one thing which I cannot understand. I realise how the
> >parallelograms form, representing the location maximum and minimum
> >quantities of silica and alumina which would be appropriate for chosen
> >mixtures of molecular flux combinations. What I cannot find in the text is
> >how the dots which represent actual recipes are determined. Ian gives
> >thirty five alternative mixtures to make up a test tile. These are not
> >spaced at regular intervals on the plot.
From Ian:
>The problem arises out of the relationship between Seger formula and weight.
>The diagram Ivor is refering to is plotted in MOLECULAR PARTS (M.P.) for a
>Seger formula (equal steps on the paper represent equal steps in molecular
>parts of alumina or silica). Volumetric blending, the basic method for
>mass-producing the glazes, is usually done in equal volumetric steps, which
>translates to equal steps in WEIGHT. (If the glazes are plotted out on a
>WEIGHT graph, the spacings along any one line blend WILL be equal.) So it
>boils down to the fact that volumetric blending and Seger formula do not sit
>well together. My (rather intuitive) understanding of the maths behind it
>all says that the culprit is the form used by Seger formula: One part
>remains constant - the fluxes at 1.0 molecular parts does not change as we
>move alumina and silica up and down. So on the diagrams showing the
>parallelogram with the 35 irregularly spaced dots there is a third player
>not shown on the graph, but which is nevertheless there.... the 1.0 of
>fluxes. The zero/zero point on the M.P. alumina/silica graph does not
>represent "nothing", it represents that mix which is 100% fluxes with no
>alumina and no silica. Note that the closer we get to the zero/zero point
>on the graph, the closer the dots get together.
>
>We can confirm the diagram is correct by doing the calculations one by one,
>or by creating one of these blends within a glaze-calc application that
>displays the glazes on an alumina/silica M.P. grid. They look just the
>same. The dots are not random, just following the maths of the relationship
>between weight and Seger formula.
>
>I've put a lot of thought into the best compromise between speed/simplicity
>on the one hand and theoretical effectiveness on the other. I am now using
>and teaching a "Recipe Method" equivalent of the method outlined in
>"Stoneware Glazes - A Systematic Approach". The starting point glaze is
>identical by each method (it's the one we choose) and what were originally
>the alumina/silica limits are now kaolin/silica limits. In some cases the
>new sets are practically identical, but many are different, but we still get
>the same sort of wide variation of alumina and silica with one set of
>fluxes, even though we might not know what this is in Seger formula terms.
>The recipe-base now allows those without any understanding of Seger formula
>to use this powerful method of finding and understanding glazes. I've
>written a new book on this extension of my original approach. It will be
>available very soon. The new recipe graph of dots (glazes) is still
>squished out of shape!! but in a new way. I think the method manages to
>combine speed, simplicity, convenience, theoretical effectiveness (showing
>HOW glazes work), going to the limits, and reflecting normal glaze practice.
>But no matter how I looked at it, there was no way I could do all this and
>come up with something with nice neat rectangular corners on paper. Sorry!
>We are up against a higher authority here.... :)
>
>Incidentally, there is little difference between the original Seger-based
>method, and the new recipe-based method, except more people will understand
>the latter. And while we're on the subject.....
>[It is apparently untrue that the Seger Formula Guild has placed a fatwah
>upon Ian Currie for violation of Guild secrets and principles.
>In a press conference today a spokesperson for Mr. Currie denied he is in
>hiding, and quoted him as saying, "Some of my best friends use Seger
>formula. I have used it myself in the past, though I didn't inhale. I
>spoke with the Grand Calculator only last week, and she was quite
>complimentary about my new book and asked me to sign her copy. With the
>sort of glaze calculation software you can get these days it doesn't matter
>if you use Seger formula, recipe, oxide weight or Betsey Linton's Teaspoon
>Method. They all work. This is a complete beat-up and is getting quite out
>of hand. "
>from "Revealing Glazes - Using the Grid Method" by Ian Currie (Bootstrap
>Press)... soon to be released.]
>
>Cheers
>
>Ian
| |
|
