Llewellyn Kouba on thu 13 sep 01
Some time ago I had gotten a large bag of vermiculite from a friend who
runs a greenhouse. I was going to add it to clay and after the product
burns out you have a very textured item. Within the past few months I saw
a documentary on TV which showed how the authorities have shut the mine
down in (town ? in Montana) and that it is carcinogenic and the locals were
even putting the stuff in gardens and all over as it was a good mulch. I
believe it is like a form of asbestos and now I am afraid to fire with it
and feel it would also have residue left over in future firings if I was to
make use of it. I think it is best now that I don't even touch the stuff.
Llewellyn Kouba
Abbey Pottery
Cindy Strnad on thu 13 sep 01
Llewellyn,
Some vermiculite is contaminated (not all) with asbestos. Monona would know
how to find out and how to ensure that what you're using is of the less
dangerous variety. Meantime, I'd leave it in the bag.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
Doug Gray on fri 14 sep 01
Llewellyn,
I have not heard the reports you speak of but you can get similar
results using organic materials. I believe there is a long tradition of
wedging rice into porcelain before throwing, so that upon firing the
rice burns out leaving thin areas for glaze to pool and light to pass
through. I've also used sawdust, but most anything will do. You might
want to limit this process though if you are bisque firing in an
electric kiln. Burning that much organic material can shorten the life
of your elements. I'm going to try coating a small electric kiln (and
elements) with ITC to see if this type of process could be done more
regularly without damaging the kiln or elements. I should also probably
mention that you don't want to be a round to inhale the fumes produced
as all that stuff burns out, organic or not, it's not good for you.
doug, SC
Date: Thu, 13 Sep 2001 09:54:30 -0600
From: Llewellyn Kouba
Subject: Vermiculite safety
Some time ago I had gotten a large bag of vermiculite from a friend who
runs a greenhouse. I was going to add it to clay and after the product
burns out you have a very textured item. Within the past few months I
saw
a documentary on TV which showed how the authorities have shut the mine
down in (town ? in Montana) and that it is carcinogenic and the locals
were
even putting the stuff in gardens and all over as it was a good mulch.
I
believe it is like a form of asbestos and now I am afraid to fire with
it
and feel it would also have residue left over in future firings if I was
to
make use of it. I think it is best now that I don't even touch the
stuff.
Llewellyn Kouba
Abbey Pottery
John Baymore on sat 15 sep 01
Within the past few months I saw
a documentary on TV which showed how the authorities have shut the mine
down in (town ? in Montana) and that it is carcinogenic and the locals we=
re
even putting the stuff in gardens and all over as it was a good mulch. I=
believe it is like a form of asbestos and now I am afraid to fire with it=
and feel it would also have residue left over in future firings if I was =
to
make use of it. I think it is best now that I don't even touch the stuff=
.
Llewellyn,
It has been shared in PARTS of the ceramics community that vermiculite ca=
n
be contaminated with asbestos for a LONG time. Unfortunatley, not
everyone heard it or believed it if they heard. Those that didn't believ=
e
it didn't pass the info along to their students or apprentices or employe=
es
or whatever. So....... sorry you are apparently just hearing about it.
It is not that vermiculite itself is carcinogenic.... it is that
vermiculite and asbestos often occur in the same rock formations. When
they mine vermiculite (just dig rocks out of the ground), they sometimes
get asbestos in there too. No simple (read "cheap") way to separate the=
m.
The TV special you mention (if it is the same on I saw a long while back=
)
is of a place that supplied a LOT of the vermiculite used in this whole
country....... and that particular mine seems to have been HEAVILY
contaminated with asbestos.
This is why the concerns over some types of talc (used in glazes....and
some bath powder!!!!) occur too....... a similar mining issue.
So the stuff in the bag of vermiculite is often of a bit uncertain exact
composition. Treat all vermiculite with respect. =
Call the supplier of the vermiculite in question and get a MSDS for it. =
Ask some detailed questions. Or just skip it. Your choice. =
If the bag of stuff is old.... it may just have come from that company yo=
u
mentioned . =
There are inherent risks in most ANY material you chose to use. Do some
research. Remember the jokes about breathing too much of the commonly
employed dihydrogen oxide (water) . Get "Artist Beware" by Dr. Michae=
l
McCann and "Keeping Claywork Safe and Legal" by Monona Rossol, and "The
Artist's Complete Health and Safety Guide" also by Monona. They are all
written for artists.... good first reads on the whole health subject. =
There are other more industrial and medical references that cover
materials...... but more designed for the health care professional.
Best,
..............................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"Earth, Water, and Fire Noborigama Woodfiring Workshop 2002 Dates TBA"=
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