Paul Lewing on tue 1 mar 05
I've recently found out that most of the contemporary research in china
paint chemistry is directed at getting rid of lead. And I was surprised to
learn that it is being replaced with bismuth (I had assumed it was being
replaced with potassium and boron).
I know very little about bismuth, except that it melts at about the same
temperature as lead, and is not toxic. What else can anybody out there tell
me?
How does it compare to lead as to color response?
Are there colors that are better, worse, or different?
How do the coefficients of expansion compare?
Does bismuth volatilize?
How durable and stable would bismuth china paints be?
Are bismuth oxide and bismuth subnitrate the only sources?
Is it expensive?
Paul Lewing, Seattle
Edouard Bastarache Inc. on wed 2 mar 05
Paul,
for its toxicology, visit :
http://perso.wanadoo.fr/smart2000/bismuth.htm#english
Later,
"Ils sont fous ces quebecois"
"They are insane these quebekers"
"Están locos estos quebequeses"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
Snail Scott on sat 5 mar 05
At 08:23 PM 3/1/2005 -0800, you wrote:
>I know very little about bismuth...
Bismuth nitrate is used to produce white patinas
on bronze. It is fairly pricey in that form
(crystals from a chemical supply house) - I recall
about $40 for 4 ounces, but it does get diluted
quite a bit for use, about 50 grams to a liter.
I know nothing of its applicability for glazes.
-Snail
Ditmar on sat 5 mar 05
FYI Bismuth is available from Seattle Pottery Supply.
A very reasonable $18 / lb. ( Prices may be higher from the catalog I have
on hand.)
800 522-1975
Ditmar
----- Original Message -----
From: "Snail Scott"
To:
Sent: Saturday, March 05, 2005 4:23 AM
Subject: Re: Bismuth vs. lead
> At 08:23 PM 3/1/2005 -0800, you wrote:
> >I know very little about bismuth...
>
> Bismuth nitrate is used to produce white patinas
> on bronze. It is fairly pricey in that form
> (crystals from a chemical supply house) - I recall
> about $40 for 4 ounces, but it does get diluted
> quite a bit for use, about 50 grams to a liter.
> I know nothing of its applicability for glazes.
>
> -Snail
>
>
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Patricia Dailey on sun 6 mar 05
Hi,
I have used bismuth subnitrate ($90 per pound), for raku and luster glazes. It is a
substitute for lead, and used in the same percentages as you might use lead. I
believe that it is much safer than lead. I think the colors are better especially luster
type glazes. I also think they might be a bit more permanent than just the usual raku
glazes, but I'm not actually sure of that. Perhaps the colors are brighter to begin with
and thus last a bit longer. You can also get some very interesting melting patterns
with raku if you watch the firing and pull at the right time. They seem to me to be
similar to the melting patters of wood firings. Hope this helps.
Patricia Dailey
Steve Irvine on sun 6 mar 05
>I know very little about bismuth, except that it melts at about the same
>temperature as lead, and is not toxic. What else can anybody out there tell
>me?
Paul,
I've used bismuth subnitrate to give a mother of pearl lustre to salt glaze ware. It was put in a
small steel cup welded to a rebar and introduced through a kiln port when the kiln had cooled to
dull, cherry red. The bismuth volitized and the vapour bonded to the surfaces of nearby pieces.
Hope this helps.
Steve Irvine
http://www.steveirvine.com
Rick Hamelin on sun 6 mar 05
Hey
Checkout http://www.pepto-bismol.com/faqs.shtml#13 for things such as:
"The active ingredient in Pepto-Bismol contains bismuth. When a small amount of bismuth combines with trace amounts of sulfur in your saliva and gastrointestinal tract, a black-colored substance (bismuth sulfide) is formed. This discoloration is temporary and harmless. It can last several days after you stop taking Pepto-Bismol. Individual bowel habits, your age (the intestinal tract slows down with age), and the amount of the product taken all help to determine how long Pepto-Bismol is in your system."
I recall that the Mother-of-Pearl overglaze is bismuth subnitrate.
Rick
--
"Many a wiser men than I hath
gone to pot." 1649
-------------- Original message --------------
> Hi,
> I have used bismuth subnitrate ($90 per pound), for raku and luster glazes. It
> is a
> substitute for lead, and used in the same percentages as you might use lead. I
> believe that it is much safer than lead. I think the colors are better
> especially luster
> type glazes. I also think they might be a bit more permanent than just the
> usual raku
> glazes, but I'm not actually sure of that. Perhaps the colors are brighter to
> begin with
> and thus last a bit longer. You can also get some very interesting melting
> patterns
> with raku if you watch the firing and pull at the right time. They seem to me
> to be
> similar to the melting patters of wood firings. Hope this helps.
> Patricia Dailey
>
> ______________________________________________________________________________
> 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.
Paul Lewing on sun 6 mar 05
on 3/6/05 8:27 AM, Rick Hamelin at piedpotterhamelin@COMCAST.NET wrote:
> I recall that the Mother-of-Pearl overglaze is bismuth subnitrate.
Actually, it's the flux in all liquid lusters.
Paul Lewing, Seattle
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