Maid O'Mud Pottery on sun 31 oct 99
Diane
I fire ^10 oxidation (electric) and used my clear as a base for a wonderful
chrome/tin pink - just added .15 (that's point .15) chrome and 5 tin. (my
studio mate has died and gone to heaven!) Try it with your trusty clear and let
us know how it works.
Also, check the archives for chrome/tin ^6-7 pink - I've heard it's wonderful
too.
Diane Schanz wrote:
> ----------------------------Original message----------------------------
> I forgot to add that I have already tried Mason stains and the reds burn out
> at high temps. I'm working with reds, browns, yellows, and oranges at the
> moment (^6 oxidation).
>
> Just made my 9,000th phone call of the day and was told by a supplier that
> Mason has three new inclusion stains: Lobster, Tangerine, and Chrome Tin
> Violet, that are supposed to fire up to 2300 C. The tech support at Mason
> didn't let me in on this, also told me that any Chrome/Tin stain would burn
> out at higher temps.
>
> Anyone tried these new stains at high temps? Thanks.
>
> Diane in Tucson
--
sam - alias the cat lady
SW Ontario CANADA
http://www.geocities.com/paris/3110 scuttell@odyssey.on.ca
"First, the clay told me what to do
Then, I told the clay what to do
Now; we co-operate"
sam, 1994
Llewellyn Kouba on tue 2 nov 99
At 11:31 PM 10/31/99 EST, you wrote:
>----------------------------Original message----------------------------
>Diane
>
>I fire ^10 oxidation (electric) and used my clear as a base for a wonderful
>chrome/tin pink - just added .15 (that's point .15) chrome and 5 tin. (my
>studio mate has died and gone to heaven!) Try it with your trusty clear
and let
>us know how it works.
>
>Also, check the archives for chrome/tin ^6-7 pink - I've heard it's wonderful
>too.
>
>Diane Schanz wrote:
>
>--------
Dear Diane,
Can you do this 'pinkie' thing in reduction? I do cone 9 reduction firings
and have tried pinks before without any success.
> ----------------------------Original message----------------------------
>> I forgot to add that I have already tried Mason stains and the reds burn
out
>> at high temps. I'm working with reds, browns, yellows, and oranges at the
>> moment (^6 oxidation).
>>
>> Just made my 9,000th phone call of the day and was told by a supplier that
>> Mason has three new inclusion stains: Lobster, Tangerine, and Chrome Tin
>> Violet, that are supposed to fire up to 2300 C. The tech support at Mason
>> didn't let me in on this, also told me that any Chrome/Tin stain would burn
>> out at higher temps.
>>
>> Anyone tried these new stains at high temps? Thanks.
>>
>> Diane in Tucson
>
>--
>sam - alias the cat lady
>SW Ontario CANADA
>http://www.geocities.com/paris/3110 scuttell@odyssey.on.ca
>
>"First, the clay told me what to do
> Then, I told the clay what to do
> Now; we co-operate"
>sam, 1994
>
John Hesselberth on tue 2 nov 99
Maid O'Mud Pottery wrote:
>> Just made my 9,000th phone call of the day and was told by a supplier that
>> Mason has three new inclusion stains: Lobster, Tangerine, and Chrome Tin
>> Violet, that are supposed to fire up to 2300 C. The tech support at Mason
>> didn't let me in on this, also told me that any Chrome/Tin stain would burn
>> out at higher temps.
>>
>> Anyone tried these new stains at high temps? Thanks.
Just a thought for anyone who does try these Cerdec inclusion pigments.
Most, if not all, contain cadmium. While it may well be that the cadmium
is well encapsulated and will not be released into food or whatever else
is put in the pot, use of cadmium in glazes is subject to careful
regulation here in the U.S. and, I suspect, other countries as well (just
like lead only the allowable leaching levels are quite a bit lower).
Specifically a potter is required to carry out a regular testing program
to prove that the final product does not leach above the allowable
levels. The fact that the stain manufacturer certifies that they are
safe is not sufficient. You MUST have the final product tested yourself
by a certified testing laboratory and you must do it regularly. I
believe there are also certain records keeping requirements. In other
words, lots of additional expense and red tape is required to stay legal.
Also, of course, you could no longer state that your glaze was
cadmium-free.
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"It is time for potters to claim their proper field. Pottery in its pure
form relies neither on sculptural additions nor on pictorial decorations.
but on the counterpoint of form, design, colour, texture and the quality
of the material, all directed to a function." Michael Cardew in "Pioneer
Pottery"
Ron Roy on wed 3 nov 99
WE are regulated as well - lead and cadmium - there are reports of
government agents buying hand made pots to be tested there and here
(USA and Canada.)
But - if the glaze is on the outside only and about 3/8 inches below
the rim they don't care.
They do work at high our high temperatures.
RR
>----------------------------Original message----------------------------
>Maid O'Mud Pottery wrote:
>
> >> Just made my 9,000th phone call of the day and was told by a supplier that
> >> Mason has three new inclusion stains: Lobster, Tangerine, and Chrome Tin
> >> Violet, that are supposed to fire up to 2300 C. The tech support at Mason
> >> didn't let me in on this, also told me that any Chrome/Tin stain
>would burn
> >> out at higher temps.
> >>
> >> Anyone tried these new stains at high temps? Thanks.
>
>Just a thought for anyone who does try these Cerdec inclusion pigments.
>Most, if not all, contain cadmium. While it may well be that the cadmium
>is well encapsulated and will not be released into food or whatever else
>is put in the pot, use of cadmium in glazes is subject to careful
>regulation here in the U.S. and, I suspect, other countries as well (just
>like lead only the allowable leaching levels are quite a bit lower).
>Specifically a potter is required to carry out a regular testing program
>to prove that the final product does not leach above the allowable
>levels. The fact that the stain manufacturer certifies that they are
>safe is not sufficient. You MUST have the final product tested yourself
>by a certified testing laboratory and you must do it regularly. I
>believe there are also certain records keeping requirements. In other
>words, lots of additional expense and red tape is required to stay legal.
>
>Also, of course, you could no longer state that your glaze was
>cadmium-free.
>
>John Hesselberth
>Frog Pond Pottery
>P.O. Box 88
>Pocopson, PA 19366 USA
>EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
>
>"It is time for potters to claim their proper field. Pottery in its pure
>form relies neither on sculptural additions nor on pictorial decorations.
>but on the counterpoint of form, design, colour, texture and the quality
>of the material, all directed to a function." Michael Cardew in "Pioneer
>Pottery"
Ron Roy
93 Pegasus Trail,
Scarborough, Ontario
Canada. M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Jonathan Kaplan on wed 3 nov 99
I agree with John Hesselberth completely about he necessity of having not
only your glazes tested, but even more so, just becuase these new pigments
are encapsulated, does not mean that then can release cadmium. It all
depends on temperature and the glaze base that you are using. While these
new pigments open up new areas for potters, let us have our ware tested
before committing these expensive stains to production on the interiors of
our pots.
BTW, I have used both Cerdec and the new Mason pigments in both oxidation
and reduction atmospheres on test wares in a variety of glaze bases. These
colors are quite remakable. The new Mason"Lobster" is quite the red at cone
4.
Jonathan
Jonathan Kaplan
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
jonathan@csn,net
http://www.sni.net/ceramicdesigin
Carenza Hayhoe on wed 3 nov 99
Dear Diane - I found a delicious Chrome/tin pink ^6 glaze by accident and
couldn't think how it had come about as I had used no chrome in a supposedly
white tin glaze. To cut a very long story short some whiting comes from
chalk beds containing fossilised mussel shells. According to Frank and
Janet Hamer's Dictionery mussel shells contain trace elements of chrome.
Just in case your whiting came from mussel beds and contains trace elements
of chrome here is the recipe -
Glaze no.7.11 Shell Pink
Nepheline syenite 35
HVAR 10
Bentonite 2
Whiting 15
Quartz 19
Frit 2268 Calcium Borate 9
Tin Oxide 10
I hope it works for you
Carenza Hayhoe
www.mochaware.com
----- Original Message -----
From: Llewellyn Kouba
To:
Sent: Tuesday, November 02, 1999 3:55 PM
Subject: Re: Chrome/tin pink WAS underglaze hardness, pool tile addendum
> ----------------------------Original message----------------------------
> At 11:31 PM 10/31/99 EST, you wrote:
> >----------------------------Original message----------------------------
> >Diane
> >
> >I fire ^10 oxidation (electric) and used my clear as a base for a
wonderful
> >chrome/tin pink - just added .15 (that's point .15) chrome and 5 tin.
(my
> >studio mate has died and gone to heaven!) Try it with your trusty clear
> and let
> >us know how it works.
> >
> >Also, check the archives for chrome/tin ^6-7 pink - I've heard it's
wonderful
> >too.
> >
> >Diane Schanz wrote:
> >
> >--------
>
> Dear Diane,
>
> Can you do this 'pinkie' thing in reduction? I do cone 9 reduction
firings
> and have tried pinks before without any success.
>
>
>
>
>
>
> > ----------------------------Original message----------------------------
> >> I forgot to add that I have already tried Mason stains and the reds
burn
> out
> >> at high temps. I'm working with reds, browns, yellows, and oranges at
the
> >> moment (^6 oxidation).
> >>
> >> Just made my 9,000th phone call of the day and was told by a supplier
that
> >> Mason has three new inclusion stains: Lobster, Tangerine, and Chrome
Tin
> >> Violet, that are supposed to fire up to 2300 C. The tech support at
Mason
> >> didn't let me in on this, also told me that any Chrome/Tin stain would
burn
> >> out at higher temps.
> >>
> >> Anyone tried these new stains at high temps? Thanks.
> >>
> >> Diane in Tucson
> >
> >--
> >sam - alias the cat lady
> >SW Ontario CANADA
> >http://www.geocities.com/paris/3110 scuttell@odyssey.on.ca
> >
> >"First, the clay told me what to do
> > Then, I told the clay what to do
> > Now; we co-operate"
> >sam, 1994
> >
>
>
Ray Aldridge on thu 4 nov 99
At 05:50 PM 11/3/99 EST, you wrote:
>----------------------------Original message----------------------------
>
>I agree with John Hesselberth completely about he necessity of having not
>only your glazes tested, but even more so, just becuase these new pigments
>are encapsulated, does not mean that then can release cadmium. It all
>depends on temperature and the glaze base that you are using.
This is something I've wondered about. Hamer calls these cadmium colors
"fugitive" and says that the red is a cadmium selenide-- that the selenium
volatizes rapidly and must be fired quickly and protected from oxidation or
it disappears from the glaze.
So my question is this: how could these colors survive a high fire unless
the protective encapsulation retains its integrity? If they can retain
their integrity in the violently active medium of a molten glaze at high
temperature, how likely is it that a mild acid would breach this integrity?
Finally, does anyone have any actual verifiable evidence that any glaze
made with these colors has actually leached cadmium?
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Ron Roy on fri 5 nov 99
The question is - how much of the Cadmium is perfectly encapsulated. There
is no doubt in my mind that if all the Cadmium is encapsulated in a zircon
crystal there will be no release. There is bound to be some Cadmium that is
not perfectly encapsulated - how much and does it vary from batch to batch
is our concern if those stains are to be used in glazes in contact with
food.
Those of you who want to use encapsulated Cadmium stains where they can
come in contact with food might consider having the ware tested. The Alfred
analytical lab will test for Cadmium release - just send a cup with the
glaze on the inside. Cost will be $20 US - $10 for the leach test and $10
to analyse for each element - in this case specify Cadmium.
This is a real bargain folks - this kind of work will cost well over $100
at other labs.
RR
>----------------------------Original message----------------------------
>At 05:50 PM 11/3/99 EST, you wrote:
>>----------------------------Original message----------------------------
>>
>>I agree with John Hesselberth completely about he necessity of having not
>>only your glazes tested, but even more so, just becuase these new pigments
>>are encapsulated, does not mean that then can release cadmium. It all
>>depends on temperature and the glaze base that you are using.
>
>This is something I've wondered about. Hamer calls these cadmium colors
>"fugitive" and says that the red is a cadmium selenide-- that the selenium
>volatizes rapidly and must be fired quickly and protected from oxidation or
>it disappears from the glaze.
>
>So my question is this: how could these colors survive a high fire unless
>the protective encapsulation retains its integrity? If they can retain
>their integrity in the violently active medium of a molten glaze at high
>temperature, how likely is it that a mild acid would breach this integrity?
>
>Finally, does anyone have any actual verifiable evidence that any glaze
>made with these colors has actually leached cadmium?
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
John Hesselberth on fri 5 nov 99
Ray Aldridge wrote:
>This is something I've wondered about. Hamer calls these cadmium colors
>"fugitive" and says that the red is a cadmium selenide-- that the selenium
>volatizes rapidly and must be fired quickly and protected from oxidation or
>it disappears from the glaze.
>
>So my question is this: how could these colors survive a high fire unless
>the protective encapsulation retains its integrity? If they can retain
>their integrity in the violently active medium of a molten glaze at high
>temperature, how likely is it that a mild acid would breach this integrity?
>
>Finally, does anyone have any actual verifiable evidence that any glaze
>made with these colors has actually leached cadmium?
>
>Ray
>
>Aldridge Porcelain and Stoneware
>http://www.goodpots.com
Ray, Hammer and Hamer are referring to plain old CdSe and CdS with their
comments. These inclusion stains are a horse of a different color. I
don't know how they work--one of these days I'll see if I can find
Cerdec's patent--but just the fact they are stable at high temperatures
indicates they are doing something different to get their colors. I
would guess they are microencapsulating in a very high melting frit while
heavily reducing--say a frit that will take cone 20 or so. Whether that
something different also makes them resistant to leaching is something I
have no idea about. Who says the mechanism for retaining color at 1200 C
and providing leach resistance to room temperature acids are the same? I
certainly wouldn't think they were. And I could certainly propose
mechanisms by which they would leach out even though they retain their
color stability at high temperature. There's not much point in that
though; it would be pure speculation.
Nevertheless, since you are now putting cadmium into a glaze, U.S.
federal regulations require you to test to be sure it doesn't leach out
if you are putting it on a surface that could possibly be used for food.
I'm sure the first person to run the required bank of tests on these
stains will let the list know. That won't be me. I don't have any plans
to use them.
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"It is time for potters to claim their proper field. Pottery in its pure
form relies neither on sculptural additions nor on pictorial decorations.
but on the counterpoint of form, design, colour, texture and the quality
of the material, all directed to a function." Michael Cardew in "Pioneer
Pottery"
Earl Brunner on sat 6 nov 99
OK, if cadmium is fugative at Cone 10 and is not perfectly encapsulated, than
shouldn't only the encapsulated part remain? These Cerdic stains, and DeGussa
(sp) stains do not come with any precautionary statements from the manufactures
that I am aware of.
How about firing the zirconium stain by itself first and then adding it to the
glaze? At what tempurature would the zirconium begin to loose its powder form?
Ron Roy wrote:
> ----------------------------Original message----------------------------
> The question is - how much of the Cadmium is perfectly encapsulated. There
> is no doubt in my mind that if all the Cadmium is encapsulated in a zircon
> crystal there will be no release. There is bound to be some Cadmium that is
> not perfectly encapsulated - how much and does it vary from batch to batch
> is our concern if those stains are to be used in glazes in contact with
> food.
>
> Those of you who want to use encapsulated Cadmium stains where they can
> come in contact with food might consider having the ware tested. The Alfred
> analytical lab will test for Cadmium release - just send a cup with the
> glaze on the inside. Cost will be $20 US - $10 for the leach test and $10
> to analyse for each element - in this case specify Cadmium.
>
> This is a real bargain folks - this kind of work will cost well over $100
> at other labs.
>
> RR
>
> >----------------------------Original message----------------------------
> >At 05:50 PM 11/3/99 EST, you wrote:
> >>----------------------------Original message----------------------------
> >>
> >>I agree with John Hesselberth completely about he necessity of having not
> >>only your glazes tested, but even more so, just becuase these new pigments
> >>are encapsulated, does not mean that then can release cadmium. It all
> >>depends on temperature and the glaze base that you are using.
> >
> >This is something I've wondered about. Hamer calls these cadmium colors
> >"fugitive" and says that the red is a cadmium selenide-- that the selenium
> >volatizes rapidly and must be fired quickly and protected from oxidation or
> >it disappears from the glaze.
> >
> >So my question is this: how could these colors survive a high fire unless
> >the protective encapsulation retains its integrity? If they can retain
> >their integrity in the violently active medium of a molten glaze at high
> >temperature, how likely is it that a mild acid would breach this integrity?
> >
> >Finally, does anyone have any actual verifiable evidence that any glaze
> >made with these colors has actually leached cadmium?
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough
> Ontario, Canada
> M1G 3N8
> Evenings 416-439-2621
> Fax 416-438-7849
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Ray Aldridge on sun 7 nov 99
At 08:45 PM 11/6/99 EST, you wrote:
>----------------------------Original message----------------------------
>OK, if cadmium is fugative at Cone 10 and is not perfectly encapsulated, than
>shouldn't only the encapsulated part remain?
That's exactly what I've been wondering.
Ray
Aldridge Porcelain and Stoneware
http://www.goodpots.com
Ron Roy on sun 7 nov 99
Hi Earl,
There are a number of factors here. If a material is volatile - as Cadmium
is - and it is not encapsulated - then it makes it's way out of a glaze
slowly - perhaps if the firing is high and long enough it would all leave -
but it would condense on the inside of the kiln and on other pots as the
kiln cools. And continue to do so in subsequent firings - and on all the
surfaces including the food bearing.
Cadmium is a very toxic substance - and - as John has pointed out - if you
use it you will have to comply with the law.
I would not expect the manufacturer to make any statement about the safety
of their product unless they were required to by law. What we don't know is
- how reliable is the process they use, is it always the same, what is
their quality control like - in other words - what % of Cadmium is
perfectly contained in zirconium crystals in each batch. I'm not at all
concerned about the encapsulated - even in a poor glass - but if that
crystal is not complete then the Cadmium can get out.
All that is needed here is an independent lab assessment of some batches of
Cadmium stains - if they have that then all they have to do is fax them to
anyone who asks for them.
RR
>----------------------------Original message----------------------------
>OK, if cadmium is fugative at Cone 10 and is not perfectly encapsulated, than
>shouldn't only the encapsulated part remain? These Cerdic stains, and DeGussa
>(sp) stains do not come with any precautionary statements from the manufactures
>that I am aware of.
>How about firing the zirconium stain by itself first and then adding it to the
>glaze? At what tempurature would the zirconium begin to loose its powder form?
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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