Jackie Brien on sat 26 may 01
I was recently told that barium carbonate leaches out after firing and that
it's very poisonous. I understood that it was poisonous in the raw state
but thought that it was quite safe when fired.
Can anyone clarify this for me?
Thanks
Jackie
Hank Murrow on sun 27 may 01
>I was recently told that barium carbonate leaches out after firing and that
>it's very poisonous. I understood that it was poisonous in the raw state
>but thought that it was quite safe when fired.
> Can anyone clarify this for me?
>Thanks
>Jackie
dear Jackie;
If the barium is dissolved in the glaze and completely incorporated
with the silica/alumina, it will not be subject to leaching from hot and/or
acidic liquids later. but if the barium is not completely held in solution
in the glaze, it will leach out. Only way I know to determine safety, is
have the glaze tested. Of course, gross testing can be done in your studio,
as many previous posts have noted.
hank in Eugene
John Hesselberth on sun 27 may 01
on 5/26/01 8:09 PM, Jackie Brien at abrien@MAIL.PACIFICCOAST.NET wrote:
> I was recently told that barium carbonate leaches out after firing and that
> it's very poisonous. I understood that it was poisonous in the raw state
> but thought that it was quite safe when fired.
> Can anyone clarify this for me?
> Thanks
> Jackie
Hi Jackie,
Unfortunately you (nor anyone else) can't answer your question without
testing what you specifically are doing with barium carbonate. If you are
putting it in a glaze it depends on how much you are using, how well
formulated the glaze is, what temperature you fire it to (do you get it
thoroughly melted) and what colorants you might have used. The only way to
tell is to have your glaze professionally leach tested. If you are
interested in doing this you can find out how on my web site at:
http://www.frogpondpottery.com/glazetest.html
Stable glazes can be made that contain barium just like stable glazes can me
made that contain lead; however most potters have stopped using barium
containing glazes on functional work. Most of us feel it is just not worth
the risk and the trouble.
If you are using barium in clay to prevent scumming, I don't have any
information on that. It is generally thought not to be a problem since the
level used is low, but I've never seen data on that.
Regards,
John
Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.com
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
Ababi on mon 28 may 01
Hello Jacky.
Try this:
Instead of 10 Barium carbonate use 7.5 strontium carbonate. Or on a surface
that does not have to be very clear or gloss, try ten for ten whiting
instead the barium. On a white claybody it will be hard to see the
different,at least in ^6 ox. The only case you must keep the Barium is for
the pink nickel barium glaze!
Ababi Sharon
ababisha@shoval.ardom.co.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
----- Original Message -----
From: "Hank Murrow"
To:
Sent: Sunday, May 27, 2001 7:09 PM
Subject: Re: Barium Carbonate-Leaching?
> >I was recently told that barium carbonate leaches out after firing and
that
> >it's very poisonous. I understood that it was poisonous in the raw state
> >but thought that it was quite safe when fired.
> > Can anyone clarify this for me?
> >Thanks
> >Jackie
>
> dear Jackie;
>
> If the barium is dissolved in the glaze and completely
incorporated
> with the silica/alumina, it will not be subject to leaching from hot
and/or
> acidic liquids later. but if the barium is not completely held in solution
> in the glaze, it will leach out. Only way I know to determine safety, is
> have the glaze tested. Of course, gross testing can be done in your
studio,
> as many previous posts have noted.
>
> hank in Eugene
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Wade Blocker on mon 28 may 01
Ababi,
Your letter re substituting strontium carb in barium glazes making no
difference on cone 6 white stoneware is not entirely correct.I have a
lovely glaze for an indigo blue matt glaze and
have tried subbing strontium carb either in part or totally for the
barium. The results are less than satisfactory. The beauty of the original
glaze is just gone.Mia in ABQ
Erin And Rod on mon 28 may 01
Any glaze with more than 5% of Barium in it is a good canidate for leaching.
A Glaze with 20-30% of Barium should never be used on the inside of a vessel
or anywhere that the users lips could touch. As many will surely tell you on
this list Barium for the most part should just be avoided. Try substituting
Strontium Carbonate for the Barium sometimes you will not notice much
difference in glaze quality.
Rod
----- Original Message -----
From: "Jackie Brien"
To:
Sent: Saturday, May 26, 2001 5:09 PM
Subject: Barium Carbonate-Leaching?
> I was recently told that barium carbonate leaches out after firing and
that
> it's very poisonous. I understood that it was poisonous in the raw state
> but thought that it was quite safe when fired.
> Can anyone clarify this for me?
> Thanks
> Jackie
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Ababi on tue 29 may 01
Hello Mia.
I could only write only acording to my experirece. That is the copper
based , fine. the clear fine the shocking pink NO NO NO!
Ababi
----- Original Message -----
From: "Wade Blocker"
To:
Sent: Monday, May 28, 2001 6:33 PM
Subject: Re: Barium Carbonate-Leaching?
> Ababi,
> Your letter re substituting strontium carb in barium glazes making no
> difference on cone 6 white stoneware is not entirely correct.I have a
> lovely glaze for an indigo blue matt glaze and
> have tried subbing strontium carb either in part or totally for the
> barium. The results are less than satisfactory. The beauty of the
original
> glaze is just gone.Mia in ABQ
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Iveragh Ceramics on tue 29 may 01
Rod,
Not if the glaze is properly formulated and fired high enough, I've
been eating my meals off my 23%barium, 3%copper, cone 12 glazed plates
almost every day for 20 years and much to the disgust of many I am still
alive, but you may be correct and it will eventually kill me, by then I just
won't care.
Bob Hollis
----- Original Message -----
From: "Erin And Rod" <2rediron@HOME.COM>
To:
Sent: 28 May 2001 20:14
Subject: Re: Barium Carbonate-Leaching?
> Any glaze with more than 5% of Barium in it is a good canidate for
leaching.
> A Glaze with 20-30% of Barium should never be used on the inside of a
vessel
> or anywhere that the users lips could touch. As many will surely tell you
on
> this list Barium for the most part should just be avoided. Try
substituting
> Strontium Carbonate for the Barium sometimes you will not notice much
> difference in glaze quality.
>
> Rod
>
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