June Perry on mon 6 jan 03
I'm always amazed when I give someone a recipe and they fail to ask me what
clay I use, how thickly I apply it, how I fire, do I use tap water, etc.etc.
The Heinos used distilled water in their glazes, I have used at various time,
both well water and tap water in mine; but when a pinholing problem showed up
a few years ago, I tried switching to distilled to see if it would make a
difference. It didn't. The only other difference was that I had switched from
natural gas to propane and I surmised that perhaps there were some impurities
in the gas that might be affecting the glaze since everything else was the
same but the water and fuel.
If I'm using older mined gerstley with the high boron content and you take my
recipe and put in newer mined gerstley with lower boron, higher magnesium,
etc., fire on a different body, different firing schedule, different
thickness, there's a good chance you may get quite different results.
There's a lot of recalculating of old recipes now that gerstley is gone. If
you refigure a recipe from the 70's you have to allow for the variance in the
formula due to the variance in the raw materials since that time. It may not
do any good to take the recipe down to the molecular formula to redesign it
for frit instead of gerstley, if you don't know the formulas for the original
ingredients and you're using current formulas in your calculations. You might
get lucky but then again, you may not.
I keep two versions of gerstley borate in my glaze program to allow for the
old and new formulas and even then there's a lot of guesswork because
gerstley has changed so much over the years.
A recipe given to you should be viewed as a starting point.
I would suggest that if you are thrilled with your claybody, then invest in
yourself and your work and get a copy of glaze software like Insight or
Matrix,etc. and get a copy of the Ian Currie book and start analyzing and
testing.With an investment of a few days using the Ian Currie method or doing
some triaxial blends, you will find more recipes for that claybody than you
can use in a lifetime. When you consider all the time spent on hit and miss
testing of other peoples formulas, your time spent on doing your own work
will probably be much better spent in the long run.
As Mel said, it takes a long time to learn to use your glazes to their best
advantage on your work. Hamada used very few glazes, and if most of us looked
at those glazes on a little test tile, we might have discarded them as
unworthy; but his strong, honest forms, and how he used those glazes has left
us a rich body of work to please the senses and show us just what you can do
with not very good clay and a few glazes and experience.
Regards,
June Perry
http://www.angelfire.com/art2/shambhalapottery/index.html
Kathi LeSueur on mon 6 jan 03
ShambhalaPottery@AOL.COM wrote:
>I'm always amazed when I give someone a recipe and they fail to ask me what
>clay I use, how thickly I apply it, how I fire, do I use tap water, etc.etc.
>
>...... I have used at various time both well water and tap water in mine; but when a pinholing problem showed up a few years ago, I tried switching to distilled to see if it would make a
>difference..... >>
>
When I moved to south Texas in the 80's I experienced an extreme change
in one of my glazes. I was talking about it one day to one of the
nurserymen down there and he said the local water had a high percentage
of boron. When I switched to distilled water for that glaze if returned
to its original appearance. That experience taught me the importance of
water in the glaze.
Kathi
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