iandol on thu 15 jun 00
Ray, Michael and Ron,
Thank you all for responding to this question. As I suspected, those =
with a depth of knowledge use boron, either as mineral or as frit to =
achieve specific results when firing above cone 6. I have used small =
quantities in a high soda felspar glaze to eliminate a slight crazing =
problem and there is no doubt that it helps to smooth things out when =
glazing is slightly uneven. I was concerned that some recipes included =
massive amounts of Gerstley Borate even up to Cone 10. I re-read the =
article by Dr. Richard Eppler, Formulating Glazes =96 CM Vol 47 No. 6. =
June-August 1999. Quite detailed and might be regarded as required =
reading for anyone learning about glazes. His statements about Boron =
confirmed my own opinion. I had only one problem with the article. =
Understanding what Mole Percent meant was difficult when I first read =
it. I presume this means that you convert the Seger unity formula, which =
represents molecular proportions, into percentage terms as a way of =
making direct comparisons. Easy arithmetic with a calculator.
I appreciate the informaion,
Regards,
Ivor. In South OZ. Enduring brass monkey weather.
John Hesselberth on fri 16 jun 00
iandol wrote:
>Understanding what Mole Percent meant was difficult when I first read it.
>I presume this means that you convert the Seger unity formula, which
>represents molecular proportions, into percentage terms as a way of making
>direct comparisons. Easy arithmetic with a calculator.
That's exactly right Ivor. All you need to do is total the numbers in
the unity formula. Then divide each one by the total multiplying by 100
as you go. Some people feel they can better compare formulas by looking
at percentages rather than unity numbers. I think it probably has a lot
to do with the way you learned. Most of the glaze calculation programs
convert back and forth between the two very readily.
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"Pots, like other forms of art, are human expressions: pleasure, pain or
indifference before them depends upon their natures, and their natures
are inevitably projections of the minds of their creators." Bernard
Leach, A Potter's Book.
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