Yodmama@AOL.COM on thu 1 feb 01
hello.
i would like to post a message to the board with the title being the
"subject" title of this email.
has anyone found a base without gerstley that works to get the rich
chrome/tin pink that is possible? if so, please email me at yodmama@aol.com
thank you! i'm doing tests, but it is grim so far.
Charles Moore on fri 2 feb 01
Hi,
I just found a chrome/tin glaze in John Conrad's book, Ceramic Formulas: The
Complete Compendium.
It is a Translucent Semi-gloss that fires at cone 5-6.
You will find a "cut & paste" version below and an attached version (which
will have better formatting).
Luck,
Charles
CHROME/TIME TRANSLUCENT SEMI-GLOSS
Potash feldspar 53.0
Silica 18.5
Barium carb. 13.0
Whiting 6.5
Kentucky ball 4.5
EPK 4.5
Add
Chrome oxide 3.2
Tin Oxide 5.2
Comments:
Little fluidity
Stain penetrates
Color: Grayed white
Color with Chrome and Tin: gray-green
Ron Roy on fri 9 feb 01
This glaze was posred to the list over a week ago.
It has a lot of alumina and silica so I suspect it is not melting well
enough to be a durable glaze. I does have a lot of Barium in it - so until
someone has it tested I would say it is not a safe glaze for functional
ware. - not at cone 6 anyway.
In fact it looks more like a cone 10 glaze to me - It will probably look
just fine with CaO or SrO subbed in for the toxic BaO.
I am suspecious that the amount of Chrome is not right - a normal amount
for a chrome tin red glaze would be more like 0.5 as a maximum according to
Hamer. Beware the fumes of chrome.
RR
>I just found a chrome/tin glaze in John Conrad's book, Ceramic Formulas: The
>Complete Compendium.
>
>It is a Translucent Semi-gloss that fires at cone 5-6.
>CHROME/TIME TRANSLUCENT SEMI-GLOSS
>
>Potash feldspar 53.0
>Silica 18.5
>Barium carb. 13.0
>Whiting 6.5
>Kentucky ball 4.5
>EPK 4.5
>
>Add
>Chrome oxide 3.2
>Tin Oxide 5.2
>
>Comments:
>Little fluidity
>Stain penetrates
>Color: Grayed white
>Color with Chrome and Tin: gray-green
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
Farrero, Charley on fri 9 feb 01
Ron Roy is right .... as usual
Chrome /tin cone 6 (red/burgundy)
Gerstley Borate 21
Neph sy 16
Kaolin 11
whiting 20
Silica 32
Tin 5
Chrome ox. .15 (yes point15)
ron can you recalculate without GB or with sub
thanks
Charley Farrero
farrero@siast.sk.ca
Ceramics dept. WOODLAND CAMPUS
BOX 3003- PRINCE ALBERT.SK.
S6V 6G1 CANADA
ph:(306) 9537064 fax:(306) 9537099
http://www.siast.sk.ca/~woodland/dos/community/ceramic/
studio: Box 145 Meacham S0K 2V0 306-3762221
cfjj@sk.sympatico.ca
http://www.saskterra.sk.ca/profile.htm
http://www3.sk.sympatico.ca/handwave/hcharley.html
> ----------
> From: Ron Roy[SMTP:ronroy@POP.TOTAL.NET]
> Reply To: Ceramic Arts Discussion List
> Sent: Thursday, February 08, 2001 11:42 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: chrome/tin glaze that really works??
>
> This glaze was posred to the list over a week ago.
>
> It has a lot of alumina and silica so I suspect it is not melting well
> enough to be a durable glaze. I does have a lot of Barium in it - so until
> someone has it tested I would say it is not a safe glaze for functional
> ware. - not at cone 6 anyway.
>
> In fact it looks more like a cone 10 glaze to me - It will probably look
> just fine with CaO or SrO subbed in for the toxic BaO.
>
> I am suspecious that the amount of Chrome is not right - a normal amount
> for a chrome tin red glaze would be more like 0.5 as a maximum according
> to
> Hamer. Beware the fumes of chrome.
>
> RR
>
>
>
> >I just found a chrome/tin glaze in John Conrad's book, Ceramic Formulas:
> The
> >Complete Compendium.
> >
> >It is a Translucent Semi-gloss that fires at cone 5-6.
>
> >CHROME/TIME TRANSLUCENT SEMI-GLOSS
> >
> >Potash feldspar 53.0
> >Silica 18.5
> >Barium carb. 13.0
> >Whiting 6.5
> >Kentucky ball 4.5
> >EPK 4.5
> >
> >Add
> >Chrome oxide 3.2
> >Tin Oxide 5.2
> >
> >Comments:
> >Little fluidity
> >Stain penetrates
> >Color: Grayed white
> >Color with Chrome and Tin: gray-green
>
> 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.
>
evan on sun 11 feb 01
I would expect that the chromium *fumes* would be oxidized to the more
toxic hexavalent form, though. Vent your kiln.
-- Evan in W. Richland WA where a burning local question is whether
hexavalent chromium in water harms salmon eggs and newly hatched fry.
Edouard Bastarache wrote:
>
> " Chrome is a known carcinogen -
>
> RR"
>
> Hello all,
>
> What is used by potters is "green chromium oxide"(trivalent)
>
> Chromium for Potters
>
> Chromium can have a valence of 2, 3, and 6. Chromium compounds vary greatly
> in their toxic and carcinogenic effects.For this reason ACGIH divides
> chromium and its inorganic compounds in a number of groupings.
Ron Roy on sun 11 feb 01
Hi Charley,
I would prefer not to do this glaze - it is quite refractory and I'm
suspecipous that it is not durable - especially with the Barium in it.
This colour is not difficult to get - it will work in a great variety of
glazes - make sure they are high in CaO and do not have any Zinc. Hansens
5x20 will probably work fine. Add 5 tin and start with 0.1 chrome - then
0.15 then 0.2. You will get more red as you add more chrome.
Chrome is a know carcinogen - and it's fugitive when fired - any glaze with
tin in it - fired in the same kiln used for firing any glaze with chrome in
it will get some colour - for years. Volitized chrome is absorbed very
easily so vent well and pay attention - it is very easy to contaminate a
kiln room with this stuff.
RR
>Ron Roy is right .... as usual
>Chrome /tin cone 6 (red/burgundy)
>Gerstley Borate 21
>Neph sy 16
>Kaolin 11
>whiting 20
>Silica 32
>
>Tin 5
>Chrome ox. .15 (yes point15)
>ron can you recalculate without GB or with sub
>thanks
>Charley Farrero
>farrero@siast.sk.ca
>Ceramics dept. WOODLAND CAMPUS
>BOX 3003- PRINCE ALBERT.SK.
>S6V 6G1 CANADA
>ph:(306) 9537064 fax:(306) 9537099
>http://www.siast.sk.ca/~woodland/dos/community/ceramic/
>studio: Box 145 Meacham S0K 2V0 306-3762221
>cfjj@sk.sympatico.ca
>http://www.saskterra.sk.ca/profile.htm
>http://www3.sk.sympatico.ca/handwave/hcharley.html
>
>
>> ----------
>> From: Ron Roy[SMTP:ronroy@POP.TOTAL.NET]
>> Reply To: Ceramic Arts Discussion List
>> Sent: Thursday, February 08, 2001 11:42 PM
>> To: CLAYART@LSV.CERAMICS.ORG
>> Subject: Re: chrome/tin glaze that really works??
>>
>> This glaze was posred to the list over a week ago.
>>
>> It has a lot of alumina and silica so I suspect it is not melting well
>> enough to be a durable glaze. I does have a lot of Barium in it - so until
>> someone has it tested I would say it is not a safe glaze for functional
>> ware. - not at cone 6 anyway.
>>
>> In fact it looks more like a cone 10 glaze to me - It will probably look
>> just fine with CaO or SrO subbed in for the toxic BaO.
>>
>> I am suspecious that the amount of Chrome is not right - a normal amount
>> for a chrome tin red glaze would be more like 0.5 as a maximum according
>> to
>> Hamer. Beware the fumes of chrome.
>>
>> RR
>>
>>
>>
>> >I just found a chrome/tin glaze in John Conrad's book, Ceramic Formulas:
>> The
>> >Complete Compendium.
>> >
>> >It is a Translucent Semi-gloss that fires at cone 5-6.
>>
>> >CHROME/TIME TRANSLUCENT SEMI-GLOSS
>> >
>> >Potash feldspar 53.0
>> >Silica 18.5
>> >Barium carb. 13.0
>> >Whiting 6.5
>> >Kentucky ball 4.5
>> >EPK 4.5
>> >
>> >Add
>> >Chrome oxide 3.2
>> >Tin Oxide 5.2
>> >
>> >Comments:
>> >Little fluidity
>> >Stain penetrates
>> >Color: Grayed white
>> >Color with Chrome and Tin: gray-green
>>
>> 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.
>>
>
>______________________________________________________________________________
>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
Puddy & Co. on sun 11 feb 01
Ron,
have a question regarding the problem of chrome - tin contamination of the kiln. I
am in the frinzy of testing all those fascinating chrome-tin glazes that were posted
on the Clayart recently. Some are in the kiln right now and if anything reasonable
comes out - I will share the information . From the testing I have done so far
though I can see that it can be tricky , and I may be forced into using purple
stains rather than the original Chromium and Tin. Will the stains ("pre-fired", I
understand), cause the same problem of contamination of other tin-containing glazes?
Thank you in advance
Hanna Lewandowski
Auburn, Ontario
Ron Roy wrote:
> Hi Charley,
>
> I would prefer not to do this glaze - it is quite refractory and I'm
> suspecipous that it is not durable - especially with the Barium in it.
>
> This colour is not difficult to get - it will work in a great variety of
> glazes - make sure they are high in CaO and do not have any Zinc. Hansens
> 5x20 will probably work fine. Add 5 tin and start with 0.1 chrome - then
> 0.15 then 0.2. You will get more red as you add more chrome.
>
> Chrome is a know carcinogen - and it's fugitive when fired - any glaze with
> tin in it - fired in the same kiln used for firing any glaze with chrome in
> it will get some colour - for years. Volitized chrome is absorbed very
> easily so vent well and pay attention - it is very easy to contaminate a
> kiln room with this stuff.
>
> RR
>
> >Ron Roy is right .... as usual
> >Chrome /tin cone 6 (red/burgundy)
> >Gerstley Borate 21
> >Neph sy 16
> >Kaolin 11
> >whiting 20
> >Silica 32
> >
> >Tin 5
> >Chrome ox. .15 (yes point15)
> >ron can you recalculate without GB or with sub
> >thanks
> >Charley Farrero
> >farrero@siast.sk.ca
> >Ceramics dept. WOODLAND CAMPUS
> >BOX 3003- PRINCE ALBERT.SK.
> >S6V 6G1 CANADA
> >ph:(306) 9537064 fax:(306) 9537099
> >http://www.siast.sk.ca/~woodland/dos/community/ceramic/
> >studio: Box 145 Meacham S0K 2V0 306-3762221
> >cfjj@sk.sympatico.ca
> >http://www.saskterra.sk.ca/profile.htm
> >http://www3.sk.sympatico.ca/handwave/hcharley.html
> >
> >
> >> ----------
> >> From: Ron Roy[SMTP:ronroy@POP.TOTAL.NET]
> >> Reply To: Ceramic Arts Discussion List
> >> Sent: Thursday, February 08, 2001 11:42 PM
> >> To: CLAYART@LSV.CERAMICS.ORG
> >> Subject: Re: chrome/tin glaze that really works??
> >>
> >> This glaze was posred to the list over a week ago.
> >>
> >> It has a lot of alumina and silica so I suspect it is not melting well
> >> enough to be a durable glaze. I does have a lot of Barium in it - so until
> >> someone has it tested I would say it is not a safe glaze for functional
> >> ware. - not at cone 6 anyway.
> >>
> >> In fact it looks more like a cone 10 glaze to me - It will probably look
> >> just fine with CaO or SrO subbed in for the toxic BaO.
> >>
> >> I am suspecious that the amount of Chrome is not right - a normal amount
> >> for a chrome tin red glaze would be more like 0.5 as a maximum according
> >> to
> >> Hamer. Beware the fumes of chrome.
> >>
> >> RR
> >>
> >>
> >>
> >> >I just found a chrome/tin glaze in John Conrad's book, Ceramic Formulas:
> >> The
> >> >Complete Compendium.
> >> >
> >> >It is a Translucent Semi-gloss that fires at cone 5-6.
> >>
> >> >CHROME/TIME TRANSLUCENT SEMI-GLOSS
> >> >
> >> >Potash feldspar 53.0
> >> >Silica 18.5
> >> >Barium carb. 13.0
> >> >Whiting 6.5
> >> >Kentucky ball 4.5
> >> >EPK 4.5
> >> >
> >> >Add
> >> >Chrome oxide 3.2
> >> >Tin Oxide 5.2
> >> >
> >> >Comments:
> >> >Little fluidity
> >> >Stain penetrates
> >> >Color: Grayed white
> >> >Color with Chrome and Tin: gray-green
> >>
> >> 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.
> >>
> >
> >______________________________________________________________________________
> >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.
Puddy & Co. on sun 11 feb 01
Edouard,
thank you for so much of relevant information. It is good to know that s=
omeone out
there takes care.
Hanna Lewandowski
Auburn
Ontario
Edouard Bastarache wrote:
> " Chrome is a known carcinogen -
>
> RR"
>
> Hello all,
>
> What is used by potters is "green chromium oxide"(trivalent)
>
> Chromium for Potters
>
> Chromium can have a valence of 2, 3, and 6. Chromium compounds vary gr=
eatly
> in their toxic and carcinogenic effects.For this reason ACGIH divides
> chromium and its inorganic compounds in a number of groupings.
>
> Group #3 is =AB Trivalent chromium compounds =BB
> (Cr3+)(chromic compounds) :including chromic oxide (Cr2o3) which is gre=
en
> chromic oxide, chromic sulfate, chromic chloride, chromic potassium sul=
fate,
> and chromite
> ore.
> Green chromic oxide is the one i use and i think it is the same for all=
of
> potters; the nastiest being hexavalent chromium in group #4, i do not =
think
> governement officials would let us use the latter.
>
> So what applies is the toxicology of trivalent compounds.
>
> Routes of Absorption : Chromic salts are minimally absorbed following
> inhalation.Trivalent chromium salts are generally poorly absorbed throu=
gh
> intact skin, once the dermal barrier is broken, however, absorption may
> occur. Trivalent chromium salts are absorbed following ingestion, but o=
nly
> 1-25% of the dose ingested is absorbed.
>
> Toxicity :
> There is little evidence of significant toxicity from chromic salts,
> probably because of poor penetration of skin and mucous membranes.Derma=
titis
> from chromic salts has been reported.
>
> The lungs of some workers exposed to chromite dust have been shown to b=
e the
> seat of
> pneumoconiotic changes consisting of slight thickening of interstitial
> tissue and alveolar septa, with histological fibrosis and hyalinisation.
> A refractory plant using chromite ore to make chromite brick had no exc=
ess
> of lung cancer deaths over a 14-year period.
> Inhalation of trivalent chromium salts can cause occupational asthma.
>
> The IARC(International Agency for Research on Cancer, Lyon ,France) has
> determined that there is inadequate evidence in humans and animals for=
the
> carcinogenicity of metallic chromium and trivalent chromium compounds(I=
II).
>
> Trivalent compounds, do not appear to cause other effects associated w=
ith
> the hexavalent chromium compounds, such as chrome ulcers (hands and
> forearms), irritative dermatitis, nasal septal perforation, lung cancer=
,
> etc.
>
> Hexavalent chromium compounds :
>
> They have been implicated as responsible for such effects as ulcerated
> nasal mucosae, perforated nasal septa, rhinitis, nosebleed, perforated
> eardrums,
> pulmonary edema, asthma, kidney damage, erosion and discoloration of th=
e
> teeth, primary irritant dermatitis, sensitization dermatitis and skin
> ulceration.
>
> Certain hexavalent chromium compounds have been demonstrated to be
> carcinogenic on the basis of epidemiological investigations of workers
> and experimental studies with animals.
> In general, these tend to be of low solubility in water and, thus, are
> subdivided into two subgroups:
>
> A-Water-soluble hexavalent chromium compounds
>
> B-Water-insoluble hexavalent chromium compounds
>
> Later,
>
> Edouard Bastarache M.D.(Occupational & Environmental Medicine)
> Author of =AB Substitutions for raw ceramic materials =BB
> edouardb@sorel-tracy.qc.ca
> http://www.sorel-tracy.qc.ca/~edouardb/
>
> References :
>
> 1-Chemical Hazards of the Workplace, Proctor & Hughes.
> 2-Dangerous Properties of Industrial Materials, Sax & Lewis.
> 3-Hazardous Materials Toxicology, Sullivan & Krieger.
>
> _______________________________________________________________________=
_______
> 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@pcl=
ink.com.
Edouard Bastarache on sun 11 feb 01
" Chrome is a known carcinogen -
RR"
Hello all,
What is used by potters is "green chromium oxide"(trivalent)
Chromium for Potters
Chromium can have a valence of 2, 3, and 6. Chromium compounds vary grea=
tly
in their toxic and carcinogenic effects.For this reason ACGIH divides
chromium and its inorganic compounds in a number of groupings.
Group #3 is =AB Trivalent chromium compounds =BB
(Cr3+)(chromic compounds) :including chromic oxide (Cr2o3) which is green
chromic oxide, chromic sulfate, chromic chloride, chromic potassium sulfa=
te,
and chromite
ore.
Green chromic oxide is the one i use and i think it is the same for all o=
f
potters; the nastiest being hexavalent chromium in group #4, i do not th=
ink
governement officials would let us use the latter.
So what applies is the toxicology of trivalent compounds.
Routes of Absorption : Chromic salts are minimally absorbed following
inhalation.Trivalent chromium salts are generally poorly absorbed through
intact skin, once the dermal barrier is broken, however, absorption may
occur. Trivalent chromium salts are absorbed following ingestion, but onl=
y
1-25% of the dose ingested is absorbed.
Toxicity :
There is little evidence of significant toxicity from chromic salts,
probably because of poor penetration of skin and mucous membranes.Dermati=
tis
from chromic salts has been reported.
The lungs of some workers exposed to chromite dust have been shown to be =
the
seat of
pneumoconiotic changes consisting of slight thickening of interstitial
tissue and alveolar septa, with histological fibrosis and hyalinisation.
A refractory plant using chromite ore to make chromite brick had no exces=
s
of lung cancer deaths over a 14-year period.
Inhalation of trivalent chromium salts can cause occupational asthma.
The IARC(International Agency for Research on Cancer, Lyon ,France) has
determined that there is inadequate evidence in humans and animals for t=
he
carcinogenicity of metallic chromium and trivalent chromium compounds(III=
).
Trivalent compounds, do not appear to cause other effects associated wit=
h
the hexavalent chromium compounds, such as chrome ulcers (hands and
forearms), irritative dermatitis, nasal septal perforation, lung cancer,
etc.
Hexavalent chromium compounds :
They have been implicated as responsible for such effects as ulcerated
nasal mucosae, perforated nasal septa, rhinitis, nosebleed, perforated
eardrums,
pulmonary edema, asthma, kidney damage, erosion and discoloration of the
teeth, primary irritant dermatitis, sensitization dermatitis and skin
ulceration.
Certain hexavalent chromium compounds have been demonstrated to be
carcinogenic on the basis of epidemiological investigations of workers
and experimental studies with animals.
In general, these tend to be of low solubility in water and, thus, are
subdivided into two subgroups:
A-Water-soluble hexavalent chromium compounds
B-Water-insoluble hexavalent chromium compounds
Later,
Edouard Bastarache M.D.(Occupational & Environmental Medicine)
Author of =AB Substitutions for raw ceramic materials =BB
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
References :
1-Chemical Hazards of the Workplace, Proctor & Hughes.
2-Dangerous Properties of Industrial Materials, Sax & Lewis.
3-Hazardous Materials Toxicology, Sullivan & Krieger.
H.M. Buchanan on wed 14 feb 01
>
> There is a way to get around chrome tin flashing with a tin opasified
glaze
> - leave the tin out and replace it with double the amount of a zirconium
> silicate like Superpax,zircopax or ultrox. They will not flash pink in the
> presence of chrome.
>
> RR
>
Sorry Ron, my white glaze with zircopax may be the exception that proves
the rule but even the neochrome wire stilts blush the bottoms of this glaze.
Judi Buchanan
Ron Roy on wed 14 feb 01
Hi Hanna,
I would expect any glaze with any type of chrome - from stain or other
chrome compounds to release chrome into the atmosphere.
We did an experiment a few years ago on iron chromite. The MSDS's say this
compound is stable to the point of complete safety and there was another
company using it to make a black clay. I was concerned because a friend was
using that body.
We put a pinch of iron chromite beside a tin glaze and fired it to cone 04
and the glaze did have some red after the firing.
I must come to the conclusion that Evan is right - it is the heat we use
that liberates chrome in clays and glazes no mater what the source.
Not all chrome coloured glazes have only a little - the hunter green glazes
have upwards of 3% if I remember correctly.
There is a way to see if any stains or compounds that have chrome in them
are releasing it. Simply add 5% tin to any white or clear glaze and fire it
in the same kiln - if it flashes pink or red then chrome is present in the
atmosphere.
Chrome has now been upgraded (downgraded) from an animal carcinogen to a
human carcinogen.
Make sure your kilns are properly ventilated no mater what you are firing -
why gamble if you don't have to.
There is a way to get around chrome tin flashing with a tin opasified glaze
- leave the tin out and replace it with double the amount of a zirconium
silicate like Superpax,zircopax or ultrox. They will not flash pink in the
presence of chrome.
RR
> have a question regarding the problem of chrome - tin contamination of
>the kiln. I
>am in the frinzy of testing all those fascinating chrome-tin glazes that
>were posted
>on the Clayart recently. Some are in the kiln right now and if anything
>reasonable
>comes out - I will share the information . From the testing I have done so far
>though I can see that it can be tricky , and I may be forced into using purple
>stains rather than the original Chromium and Tin. Will the stains
>("pre-fired", I
>understand), cause the same problem of contamination of other
>tin-containing glazes?
>
>Thank you in advance
>Hanna Lewandowski
>Auburn, Ontario
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
Edouard Bastarache on wed 14 feb 01
Hello all,
not all chromium compounds are carcinogenic.
Please read the following:
"The Canadian Centre for Occupational Health and Safety states that no
adequate human or animal information on the carcinogenicity of chromium i=
s
available.
The International Agency for Research on Cancer (IARC) judges the evidenc=
e
for considering chromium VI (hexavalent) a cause of cancer at sites other
than the lungs to be insufficient. The IARC classification of carcinogeni=
c
risk is group 3 (not classifiable)"
Reference:
The Occupational aand Environmental Medicine Report, Harold E. Hoffman,
november 200
"Chrome has now been upgraded (downgraded) from an animal carcinogen to =
a
human carcinogen.
RR"
Later,
Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
| |
|
