Lee Love on sun 27 jul 08
On Sat, Jul 26, 2008 at 11:46 PM, David Woof wrote:
>copper and silver for sanitation of stored foods. I don't put barium or =
copper in food
>contact liner glazes,
David, I don't use barium at all. I primarily use copper for trailing
decoration, similar to traditional use in Mashiko. Not as a base
glaze.
Do you believe barium and copper are of equal hazard? In the past,
the primary issue with copper was in lead glazes, where copper would
allow lead to leach more easily. Edouard recognizes this in his
writeup.
When people mention them in the same sentence, they are led to
believe they are equally hazardous. Copper is closer to iron than
barium in toxicity in glazes.
Barium: http://ceramic-materials.com/cermat/education/162.html
Copper: http://ceramic-materials.com/cermat/education/178.html
Prevention from Edouard's writeup (anybody see any hazard differences?):
COPPER IX-Prevention :
Copper compounds used by potters are not considered much hazardous
if there is no ingestion of basic copper carbonate and/or
the sulfate.In glazes, copper enhances lead leaching.
Good studio housekeeping is always good practice. Avoidance of processes
generating unnecessary dust is also important and the wearing of an approve=
d
dust mask when the exposure seems hazardous is also good practice.
BARIUM Prevention :
Good housekeeping of your studio is important as for any other chemical.
Avoidance of processes generating unnecessary dust is also important.
Depending on the severity of exposure, local ventilation should be
used and the aspired air should be vented outside to avoid producing
dust from work tables and the floor.
Very effective filter masks should be worn if the severity of exposure
justifies it during preparation of glazes and clays.
It should be forbidden to drink, eat or smoke in the workshop.
Especially, one should not confuse barium carbonate with table sugar
when preparing coffee.
Barium Medical surveillance (none listed for copper) :
An electrocardiogram is recommended as part of the periodical
examination of workers exposed to soluble salts. Periodical urinary
and blood mesurements could also be carried out; in subjects not
professionally exposed blood concentrations are lower than 10 =B5g/L,
and lower than 20=B5g/L in the urine.
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"Let the beauty we love be what we do.
There are hundreds of ways to kneel and kiss the ground." --Rumi
Lee Love on mon 28 jul 08
On Mon, Jul 28, 2008 at 12:01 AM, David Woof wrote:
> Lee, Yes, I should not have used copper and barium in the same sentence.
>
> No, i do not consider copper and barium of equal hazard. I have a concern with
>copper saturation in a glaze possibly making the glaze and it's other constituents
>unstable.
That's the key. Copper can make other constituents of a glaze
more easily leached when used with acidic food. Empirical test show,
in copper and brass water containers, less than dietary amounts of
copper are released.
> My intended point, which regrettably I digressed from, was not to make claims we can
> be later held accountable for as popular knowledge shifts and spins.
I agree: if you claim to have "Mastered" the glaze, then you should be
held accountable.
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"Let the beauty we love be what we do.
There are hundreds of ways to kneel and kiss the ground." --Rumi
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