Joseph Herbert on sat 3 oct 98
Bob Wicks wrote: Try Talc. It works good.
I hate to be this way but talc may be a worse choice than flint. The major
impurity in talc is asbestos. This may only be a small fraction of a percent
but the effectiveness of Chrysotile in causing lung complications is
legendary. Perhaps a clay - like kaolin - or coarse mesh flint (to keep the
air floating fraction down) is better. Wear a respirator in any event and do
your dusting outside?? If possible.
Is a silicon spray out of the question? Anything to reduce the dust.
The presence of Chrysotile in talc is a problem that probably should be
addressed at some point. The association of the two minerals is pretty strong
so the inclusion of the asbestos minerals in talc, especially pottery grade
talc, is unavoidable. You may remember that corn starch baby powder became
popular because of this concern with the more highly refined baby talc powder.
I have wondered what this means for those grade school teachers who use a
white firing talc body (up to 50 percent talc) in their classrooms. One would
hope that their efforts at dust control would be effective and that the use of
this clay body would be limited. On the other hand, they probably don t know
if there is a health concern.
From Encyclopedia Britannia CD 1997 "Chrysotile, the fibrous form of the
mineral serpentine, is the best-known type and accounts for about 95 percent
of all asbestos in commercial use. It is a hydrous magnesium silicate with the
chemical composition of Mg SiO (OH). The other types all belong to the
amphibole group of minerals and include the fibrous forms of anthophyllite,
amosite (grunerite), crocidolite (riebeckite), tremolite, and actinolite"
Glad I don t do press molds or talc bodies much
Joseph Herbert
JJHerb@aol.com
Edouard Bastarache on sun 4 oct 98
Hello Joseph,
Pleuropulmonary disease appears to be more prevalent in workers exposed to
amphibole
than chrysotile.Chrysotile is typical of Quebec
asbestos.Chrysotile,composed of long, strong fibers,
can be spun into fabrics.Crocidolite and amosite, composed of fibers that
are resistant to heat and acid, are found in South Africa; anthophyllite
and tremolite are mined in Finland.
Later,
Edouard Bastarache M.D. (Occupational & Environmental Medicine)
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----------
> De : Joseph Herbert
> A : CLAYART@LSV.UKY.EDU
> Objet : Please release me (Press molds)
> Date : 3 octobre, 1998 15:45
>
> ----------------------------Original message----------------------------
> Bob Wicks wrote: Try Talc. It works good.
>
> I hate to be this way but talc may be a worse choice than flint. The
major
> impurity in talc is asbestos. This may only be a small fraction of a
percent
> but the effectiveness of Chrysotile in causing lung complications is
> legendary. Perhaps a clay - like kaolin - or coarse mesh flint (to keep
the
> air floating fraction down) is better. Wear a respirator in any event
and do
> your dusting outside?? If possible.
>
> Is a silicon spray out of the question? Anything to reduce the dust.
>
> The presence of Chrysotile in talc is a problem that probably should be
> addressed at some point. The association of the two minerals is pretty
strong
> so the inclusion of the asbestos minerals in talc, especially pottery
grade
> talc, is unavoidable. You may remember that corn starch baby powder
became
> popular because of this concern with the more highly refined baby talc
powder.
> I have wondered what this means for those grade school teachers who use a
> white firing talc body (up to 50 percent talc) in their classrooms. One
would
> hope that their efforts at dust control would be effective and that the
use of
> this clay body would be limited. On the other hand, they probably don t
know
> if there is a health concern.
>
> >From Encyclopedia Britannia CD 1997 "Chrysotile, the fibrous form of the
> mineral serpentine, is the best-known type and accounts for about 95
percent
> of all asbestos in commercial use. It is a hydrous magnesium silicate
with the
> chemical composition of Mg SiO (OH). The other types all belong to the
> amphibole group of minerals and include the fibrous forms of
anthophyllite,
> amosite (grunerite), crocidolite (riebeckite), tremolite, and actinolite"
>
> Glad I don t do press molds or talc bodies much
>
> Joseph Herbert
> JJHerb@aol.com
Carolynn Palmer on sun 4 oct 98
Baby powder works for me. I use the generic kind because it is cheap and
comes in larger containers. I read somewhere that the manufacturers of baby
powder took the talc out of it.
I've found that it works really well in my press molds. I powder my mold
liberally, let it stand a few moments to absorb the moisture, then tap the
mold upside down over a wastebasket to get rid of the excess powder.
When the press mold becomes too damp from repeated use, I dry it for a few
minutes with a hair dryer.
Carolynn Palmer, Somerset Center, Michigan
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