Just finished reading "Uncommon Clay" (easily found at the library). Good
read, though the bit about a professional potter not knowing about or
understanding glazes nags at me. Toxicity of heavy metals in glazes was
made more real and personal. In the U.S. only lead and cadmium are made a
clear issue of and potters in general really don't have clear guidelines on
the materials we use. Silica is actually one of the more dangerous
materials and it is in almost everything you would find in a studio. Few
people know that. Making our pots 'safe' for once they leave the studio is
an entirely different issue and one which seems to be the most confused.
Pinnel's Weathered bronzed green has been taken off our shelf - either
because

1 - it has Lithium in it and that could be dangerous especially to someone
taking Lithium
2 - it could possibly leach copper - it is fine to whip you eggs in a copper
bowl but you don't know that some end user is not going to put orange juice
in what you made and end up with more copper than they should have and yucky
tasting orange juice...
3 - it settles like a rock unless some one is on top of it all the time

or all 3.

Most of the more beautiful and interesting glazes (for me and many others -
for example I love the alkali and barium blues) do not stand up to the rules
set by MC6 (Ron Roy and John Hesselberth's book) or they do not work in a
studio situation (runny glazes can be yummy but not worth the $$$ for
shelves).

People in our studio keep coming to me with glazes they want made that are
very high in metal oxides (6% Cu for example) with the minimum amount of
silica. I can almost guarantee them that the glaze will leach metal and not
be stable but that is meaningless to them because there really is no
standard I can point to. There is no "Food Save" criterion. I do wish we
would come to some conclusions on this issue rather than say all insides of
pots should not have any metal oxide in the glaze.

Donna


"Bob Masta" wrote in message
...
Semi-OT:

Potters who are also mystery lovers may enjoy "Uncommon Clay" by
Margaret Maron, a mystery involving Judge Deborah Knott and a family
of North Carolina potters that seems to be marked for death.

The pottery aspects are presented fairly well, and the plot is pretty
good. However, the author spends a *lot* of time on character
development, so this may not be for those who like cut-to-the-chase
action. My wife and I listened to it as a recorded book (from the
local library) on a trip this past weekend, and it seemed slow getting
started to me, whereas she had no problems with it. (She selects the
recordings, because she is a weaver and has already listened to most
of the library collection while working at her loom... if I picked,
she would be sure to have heard it already!) But it was fine to while
away the miles, and might be equally fine in a pottery studio.

Best regards,


Bob Masta

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