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question re scumming and barium

updated fri 29 sep 00

 

Rod, Marian, and Holly Morris on wed 27 sep 00


I have a concern about the use of barium and I need a knowledgeable =
answer. I struggle with this problem since I use terra cotta a lot.

When I was younger and more stupid, I would mix up the glaze bucket with =
my hands. I did this at a college where I was taking a workshop, and =
after a minute or so in a particular bucket, I became very flushed, my =
heart started racing, I nearly passed out, and then sat sweating for ten =
minutes to recover (sounds like a typical hot flash, but I was twenty =
eight at the time).

I asked many potters about that incident, and some speculated that I =
might have ingested a glaze ingredient through my skin- and that barium =
(carbonate, not sulfate) could be the culprit because of its known =
effect on the the heart)

So the question is- when we put barium in the clay, are we putting =
ourselves at risk for ingesting it through the skin? Is is safe in the =
classroom? I would love to hear that it IS safe, because scumming is a =
real detriment to the finished product, and so far the best cure I have =
encountered is suggested to me here- to apply some light vegetable oil =
to the fired clay. Doesn't remove the scumming, but does conceal it.

Marian in Michigan, shivering

Paul Kaye on wed 27 sep 00


In the brick industry they use a product called Lignosol. I have looked it
up on the net but can only get the information from the company. I have
looked for government safety sheets on this product and have found nothing
(I probably am looking in the wrong place).
It is a byproduct of the pulp and paper industry and has many uses. One of
the uses is to minimize the salts scumming in clay.
In some tests that I have done with it the one problem is that it seems very
organic and contributes to a lot of fumes from the kiln in the initial
stages of the firing.
I will post information on this product as it becomes available.
PK


>From: "Rod, Marian, and Holly Morris"
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Question re Scumming and Barium
>Date: Wed, 27 Sep 2000 08:45:23 -0400
>
>I have a concern about the use of barium and I need a knowledgeable answer.
>I struggle with this problem since I use terra cotta a lot.
>
>When I was younger and more stupid, I would mix up the glaze bucket with my
>hands. I did this at a college where I was taking a workshop, and after a
>minute or so in a particular bucket, I became very flushed, my heart
>started racing, I nearly passed out, and then sat sweating for ten minutes
>to recover (sounds like a typical hot flash, but I was twenty eight at the
>time).
>
>I asked many potters about that incident, and some speculated that I might
>have ingested a glaze ingredient through my skin- and that barium
>(carbonate, not sulfate) could be the culprit because of its known effect
>on the the heart)
>
>So the question is- when we put barium in the clay, are we putting
>ourselves at risk for ingesting it through the skin? Is is safe in the
>classroom? I would love to hear that it IS safe, because scumming is a real
>detriment to the finished product, and so far the best cure I have
>encountered is suggested to me here- to apply some light vegetable oil to
>the fired clay. Doesn't remove the scumming, but does conceal it.
>
>Marian in Michigan, shivering


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Snail Scott on wed 27 sep 00


>
>So the question is- when we put barium in the clay, are we putting
ourselves at risk for ingesting it through the skin? Is is safe in the
classroom? I would love to hear that it IS safe, because scumming is a real
detriment to the finished product, and so far the best cure I have
encountered is suggested to me here- to apply some light vegetable oil to
the fired clay. Doesn't remove the scumming, but does conceal it.
>
>Marian in Michigan, shivering

Jeff Zamek wrote a piece for Ceramics Monthly called "Is Barium Carbonate
Safe?" (Sept.'97, p.43).
In it he covers quite a bit of the current research.

-Snail

Sharon31 on thu 28 sep 00


A different opinion:
Barium Glazes: How Safe? http://www.whistlepig.com/claytimes/barium1.htm

Common Sense about Barium Leaching, Part II
http://www.whistlepig.com/claytimes/barium2.htm

Testing for Barium Leaching, Part III
http://www.whistlepig.com/claytimes/barium3.htm

by Monona Rossol


Ababi