Frank Martin on fri 26 may 00
Michael -
The source for my volcanic ash now is France.
I have used other volcanic ash, ( various small amounts in unmarked bags
)
and they all equally close to what I use now.
Frank Martin
92nd Street Y
Art Center
1395 Lexington Avenue,
New York, NY. 10128.
email - fmartin@92ndsty.org
email - pmartin@92ndsty.org
Call - (212) 996-1100
to register for programs.
or
Visit us on the web.
http://www.92ndsty.org/
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-----Original Message-----
Date: Tue, 23 May 2000 09:25:40 -0700
From: Michael McDowell
Subject: Re: volcanic ash question - glazes
I've been preoccupied with my gardening of late, so I've not chipped in
on
this thread before now. Marcia, I would be suspicious that your Mt.
Saint
Helens Ash sample has somehow become contaminated if it is coming out
with a
dark blue tinge. In twenty years, things do happen. I do concur with
Paul
Lewing's information on the geographical variation in samples tested
around
the Northwest at the time of the erruption. My sources were somewhat
different, but they also showed that the material was pretty consistent
throughout the range where it was deposited. There was just a small
dropoff in
iron content with distance from the volcano as the most significant
systematic
geographic variation.
Jeff Lawrence's work with volcanic deposits from the Jemez Mountains in
New
Mexico, and the analysis he has shared here, shows how different a
material
can come from such a similar (also volcanic) source. We potters should
be
careful then to be specific as to source when offering or requesting
information regarding volcanic ash.
In this vein, I'd like to ask Frank Martin to revise the glaze formulas
he
just posted for "volcanic ash" glazes by specifying which erruption from
which
volcano, if he knows it. If not, then at least the spot from which it
was
recovered, or the supplier from whom it was purchased would help clarify
his
meaning. To say "Volcanic Ash" in a glaze formula is only slightly more
informative than saying "Powdered Rock".
Michael McDowell
Whatcom County, WA USA
mmpots@memes.com
http://www2.memes.com/mmpots
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