Craig Martell on thu 12 dec 96
Good Morning Clayart: In regard to some of the recent posts on crazing,
shivering, and other problems relating to glazes and claybodies, may I offer
some valuable references that will help all those who care to do the reading?
Oregon potter Jim Robinson has written two articles for Studio Potter that
are very enlightening on the subject of stable clay bodies and how to assess
and achieve them, and how these stable bodies react with glazes. These
articles are very readable and user friendly, as is Jim. The first is: Fear
of Silica, Studio Potter, Vol. 9, #2, June 1981. The second is: Body
Building for Potters, Studio Potter, Vol. 16 #2, June 1988. In the second
article, Jim has a series of 10 glazes, graduating from low to high
expansion, that can be applied to claybodies in order to provide info about
the clay in terms of the balance of feldspar and silica, and how this relates
to glaze fit and thermal dynamics of the clay-i.e. Will this stuff crack in
the oven? This series of glazes can be used on bodies you have developed or
are in the process of developing and commercial bodies as well. You can use
this series to find a commercial mix that is balanced and will perform well.
I must mention though, that this series and the two articles Jim wrote apply
to "high fire" clays and glazes, but there is an article in Ceramics Monthly,
June-July 1991 by Larry Clark that applies Jim's concepts to cone 5 work.
Jim told me that this is an INCREDIBLE article and he gives it the highest
reccomendation possible.
I think many of you have seen or read these articles already but if you
haven't, I would urge you to do so if you have an interest to increase your
understaning of clay and glazes, and how they work together.
Jim also told me about 2 publications that he feels are extremely valuable in
the field of glaze development. Stoneware Glazes, A Systematic Approach by
Ian Currie-published by Bootstrap Press in Australia. Perhaps some of our
online friends in Australia could provide info on how to get this book if it
is not readily available here. Jim says that Bill Morgan at Southern Oregon
Pottery Supp., in Talent, Or. has some copies. Anyway, Jim says that this is
a great book on glaze development and worth every penny you pay. Neither of
us have any connection to Ian or Bootstrap Press. Jim also recommends The
Cushing Handbook, which can be obtained from Val Cushing @ 1497 Water Wells
Rd. Alfred Station, NY 14803 (607)587-9193. The Cushing Handbook is an
excellent aid to glaze development at all temps and gives recepies and seger
formulas. Jim also said that Ian Curries book can be used at all temps as
well.
There are others on the list who have read and used Jim's methods with great
satisfaction. Perhaps some will offer additional comments, and fill in some
of the things that I have probably missed. I hope others will investigate
this stuff as well, I know it will help immensely. In talking with Jim the
other day, he reminded me of something that Michael Cardew said; that in the
history of ceramics, potters have never had access to so much technical
information as we do at present. Cardew also urged us not to turn our backs
on this information.
Regards to you all, Craig Martell-Oregon
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