Elizabeth Priddy on wed 27 jan 99
> One person or school will say manganese
> (40-80 mesh) at approx 3-4=25 in a clay batch to make spots when fired is =
> not
> I have just read 2 articles in Digital Fire's website about 2 potters with
> manganese poisioning. It was from fumes, not in the clay.
The skin is phenomenal at keeping things out of us. Manganese and other
"toxic" ingredients can be handled if handled properly. You have to know how
it is introduced into the body, to know how and WHEN it is dangerous.
Barium, for instance, if handled with gloves is not going to get you, breathe
it and it won't hurt you too much(mucus catches most of it, and you can blow
it out handily - but wear a mask for safety). But DO NOT make a cocktail
with miniscule amounts and drink it, because THAT will kill you. Wear gloves
if you are concerned. Many chemicals and minerals cannot be absorbed through
the skin, but when heated and transformed into a gas and respirated, or
ingested, can kill or sicken. Materials also can recombine as your kiln
outgasses. There is a time in firing when there is a sickly smell emitted
that you can taste at the back of your throat and feel as you breathe it in.
That is your bodies way of saying "get out!" If your kiln room is improperly
vented, you can become very sick from recombined gases that formed from even
"safe" materials. OSHA is actually a very good thing.
**************************************************
I speak from experience and sincerity, rather than authority...
Elizabeth Priddy: potter, philosopher, artist
epriddy@usa.net www.angelfire.com/nc/clayworkshop
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Craig Martell on thu 28 jan 99
Elizabeth Priddy says:
>The skin is phenomenal at keeping things out of us. Manganese and >other
"toxic" ingredients can be handled if handled properly
Hi:
According to studies, the skin isn't so efficient where manganese is
concerned. I think that proper handling of MnO2 is avoiding direct contact.
Manganese is very good at finding it's way into the body and requires very
careful handling. I avoid it, and have found ways to use other oxides in
glazes to get the color I want.
>Barium, for instance, if handled with gloves is not going to get you,
>breathe it and it won't hurt you too much(mucus catches most of it, and
>you can blow it out handily
We don't know what "too much" is, and barium carb can and will accumulate in
the body. The amount of ingestion that I go for in terms of any ceramic
material is "zero". It is impossible to attain this goal, but I think it is
still better to aim high in this regard. I use some barium and I'm very
cautious when mixing and applying the glazes. I let my mask catch whatever
may become airborne and would rather not try and expel this stuff into my
hankie.
You advocate an approach to these two materials that I would say is way too
casual.
regards, Craig Martell in Oregon
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