Edouard Bastarache on thu 13 sep 01
Hello all,
Here is a text I found on Smart-Conseil's site and translated to english =
with his permission.
Smart works for a large french pottery factory (where cadmium pigments =
are used),that produces 100,000 pieces per month. He is also a member of =
the french part of the European committee for the standardization of =
ceramic ustensils in contact with food, where the questions relating to =
glazes are largely tackled, he is certainly well aware of cadmium =
pigments in glaze safety :
" The development by Degussa of a cadmium pigment included in a zircon =
crystal (zirconium silicate Zr SiO4) made it possible to obtain a stable =
matrix at 1350=B0C which contains cadmium in a permanent way (great =
chemical stability and mechanical resistance). The release of soluble =
cadmium is extremely low.=20
Moreover, this process makes it possible to obtain the same levels of =
colouring with much less cadmium than with the traditional pigments. 10 =
to 20 times less cadmium pigment is necessary... for a same result. The =
price of the cadmium products is also lower.=20
Ceramic problems due to the dilation coefficient (crazing) and to =
bubbles are partly solved by this type of pigment. The stability of =
hues, even at weak concentrations (pastel), is excellent. "
Smart.Conseil
Le site Fran=E7ais d=E9di=E9 aux passionn=E9s de c=E9ramique
The French site dedicated to ceramics lovers
smart2000@wanadoo.fr
http://perso.wanadoo.fr/smart2000/
(Langue Fran=E7aise par d=E9faut : Tutoiement =E0 la "Qu=E9b=E9coise")
Later,
Edouard Bastarache
Irreductible Quebecois
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://www.absolutearts.com/portfolios/e/edouardb/
Ron Roy on wed 19 sep 01
I have seen photos of those crystals - enlarged - presented at a ceramic
workshop by the Degussa rep. As he noted and we could all see - some of the
crystals were not perfectly formed. In other words - some cadmium was not
encapsulated.
No doubt - glazes fired to 1350C have a much better chance of being stable
- at cone 6 you have to work harder at making stable glazes.
Remember - Cadmium is the most toxic of the oxides we use - and well
regulated. Take care in the studio to minimise contact with it and make
sure you have your glazes tested to make sure you are under the allowable
limits.
RR
>Here is a text I found on Smart-Conseil's site and translated to english
>with his permission.
>
>Smart works for a large french pottery factory (where cadmium pigments are
>used),that produces 100,000 pieces per month. He is also a member of the
>french part of the European committee for the standardization of ceramic
>ustensils in contact with food, where the questions relating to glazes are
>largely tackled, he is certainly well aware of cadmium pigments in glaze
>safety :
>
>" The development by Degussa of a cadmium pigment included in a zircon
>crystal (zirconium silicate Zr SiO4) made it possible to obtain a stable
>matrix at 1350=B0C which contains cadmium in a permanent way (great chemica=
l
>stability and mechanical resistance). The release of soluble cadmium is
>extremely low.
>
>Moreover, this process makes it possible to obtain the same levels of
>colouring with much less cadmium than with the traditional pigments. 10 to
>20 times less cadmium pigment is necessary... for a same result. The price
>of the cadmium products is also lower.
>
>Ceramic problems due to the dilation coefficient (crazing) and to bubbles
>are partly solved by this type of pigment. The stability of hues, even at
>weak concentrations (pastel), is excellent. "
>
>
>
>
>
>Smart.Conseil
>Le site Fran=E7ais d=E9di=E9 aux passionn=E9s de c=E9ramique
>The French site dedicated to ceramics lovers
>smart2000@wanadoo.fr
>http://perso.wanadoo.fr/smart2000/
>(Langue Fran=E7aise par d=E9faut : Tutoiement =E0 la "Qu=E9b=E9coise")
>
>
>
>Later,
>
>Edouard Bastarache
>Irreductible Quebecois
>Sorel-Tracy
>Quebec
>edouardb@sorel-tracy.qc.ca
>http://sorel-tracy.qc.ca/~edouardb/
>http://www.absolutearts.com/portfolios/e/edouardb/
>
>___________________________________________________________________________=
___
>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.
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
=46ax 613-475-3513
Edouard Bastarache on wed 19 sep 01
Hello Ron,
I have just sent your post to Smart-Conseil for comments.
In the mean time, if you want to know more about the toxicity
of cadmiun and compounds, my updated(Sept.2001) text is
already uploaded at 3 different places on the Net, in both
languages :
1-Smart-Conseil's site
2-Tony Hansen's
3-Claynet's
Later,
----- Original Message -----
From: Ron Roy
To:
Sent: Wednesday, September 19, 2001 12:33 AM
Subject: Re: Cadmium and Smart-Conseil
I have seen photos of those crystals - enlarged - presented at a ceramic
workshop by the Degussa rep. As he noted and we could all see - some of t=
he
crystals were not perfectly formed. In other words - some cadmium was not
encapsulated.
No doubt - glazes fired to 1350C have a much better chance of being stabl=
e
- at cone 6 you have to work harder at making stable glazes.
Remember - Cadmium is the most toxic of the oxides we use - and well
regulated. Take care in the studio to minimise contact with it and make
sure you have your glazes tested to make sure you are under the allowable
limits.
RR
>Here is a text I found on Smart-Conseil's site and translated to english
>with his permission.
>
>Smart works for a large french pottery factory (where cadmium pigments a=
re
>used),that produces 100,000 pieces per month. He is also a member of the
>french part of the European committee for the standardization of ceramic
>ustensils in contact with food, where the questions relating to glazes a=
re
>largely tackled, he is certainly well aware of cadmium pigments in glaze
>safety :
>
>" The development by Degussa of a cadmium pigment included in a zircon
>crystal (zirconium silicate Zr SiO4) made it possible to obtain a stable
>matrix at 1350=B0C which contains cadmium in a permanent way (great chem=
ical
>stability and mechanical resistance). The release of soluble cadmium is
>extremely low.
>
>Moreover, this process makes it possible to obtain the same levels of
>colouring with much less cadmium than with the traditional pigments. 10 =
to
>20 times less cadmium pigment is necessary... for a same result. The pri=
ce
>of the cadmium products is also lower.
>
>Ceramic problems due to the dilation coefficient (crazing) and to bubble=
s
>are partly solved by this type of pigment. The stability of hues, even a=
t
>weak concentrations (pastel), is excellent. "
>
>
>
>
>
>Smart.Conseil
>Le site Fran=E7ais d=E9di=E9 aux passionn=E9s de c=E9ramique
>The French site dedicated to ceramics lovers
>smart2000@wanadoo.fr
>http://perso.wanadoo.fr/smart2000/
>(Langue Fran=E7aise par d=E9faut : Tutoiement =E0 la "Qu=E9b=E9coise")
>
>
>
>Later,
>
>Edouard Bastarache
>Irreductible Quebecois
>Sorel-Tracy
>Quebec
>edouardb@sorel-tracy.qc.ca
>http://sorel-tracy.qc.ca/~edouardb/
>http://www.absolutearts.com/portfolios/e/edouardb/
>
>________________________________________________________________________=
___
___
>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.
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
_________________________________________________________________________=
___
__
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.
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