Earl Brunner on sat 5 jan 02
I was sort of suspecting that, I figured the glaze disclaimers have to
be as bad as the clay ones. Now, how to get back to the topic with her
and have some dialogue.......
Earl Brunner
mailto:bruec@anv.net
http://coyote.accessnv.com/bruec
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG] On
Behalf Of John Hesselberth
Sent: Saturday, January 05, 2002 6:41 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Safety of "commercial" glazes
on 1/5/02 4:45 PM, Earl Brunner at bruec@ANV.NET wrote:
> She blew it off
> with the statement that since the commercial glaze company said that
it
> was safe it must be. I think that she is assuming a lot. Or am I
being
> unnecessarily cautious? Since this lady teaches High School Ceramics
> I'm a little concerned. Any comments? I know that without knowing
the
> glaze or the company that any discussion has to be limited. What are
> the liability issues with using commercial glazes? Do we just assume
> that if they say it is safe that it is?
Hi Earl,
In my limited probing of commercial glazes I find that companies have
highly
variable standards for what they call "food safe". For example Spectrum
leach tests and submits their results to a toxicologist at Duke
University
for an opinion. They are the most careful I have found. Next in line
is
probably Opulence who has their glaze formulations approved by a well
known
glaze consultant--no not ours--there are another one or two that are
pretty
well known who are not Clayart members.
At the other end of the spectrum I have found commercial glazes labeled
food
safe that are so unstable I use them for my lemon juice demonstration.
You
can suck the color right out of them in less than an hour with a juicy
slice
of lemon. Now I suppose that still may be food safe depending on what
is
actually in the glaze, but these are certainly not durable glazes that
are
suitable for functional work--one of the worst was obviously colored
with
cobalt.
So I think you have to ask some tough questions of the manufacturers.
Ask
what level of testing they do. Whether or not they use barium or lead or
cadmium. Whether they are willing to make public their test results. If
you
don't get satisfactory answers, don't buy. By the way, Spectrum told me
they would tell you their test results if you were interested. I've
never
tested that, but the conversations I had with the owner and his son left
me
with the feeling they are a very professional and honorable company.
Opulence was the only one I saw who had lemon slices on some of their
own
glazes the morning after I gave my talk at NCECA last March. That's
confidence in your product!
Regards,
John
And, believe me, they disclaim liability for getting up in the morning.
Their disclaimer statements attempt to put the liability straight on the
user.
Earl Brunner on sat 5 jan 02
We were having a guild board meeting the other day and one of the
officers brought in a couple of pieces that she had used commercial
glazes on. I think they were cone 6 glazes. One looked exactly like a
copper blue glaze. Since most copper blue glazes that I know of use
barium carbonate, I questioned the safety of the glaze. She blew it off
with the statement that since the commercial glaze company said that it
was safe it must be. I think that she is assuming a lot. Or am I being
unnecessarily cautious? Since this lady teaches High School Ceramics
I'm a little concerned. Any comments? I know that without knowing the
glaze or the company that any discussion has to be limited. What are
the liability issues with using commercial glazes? Do we just assume
that if they say it is safe that it is?
Earl Brunner
mailto:bruec@anv.net
http://coyote.accessnv.com/bruec
John Hesselberth on sat 5 jan 02
on 1/5/02 4:45 PM, Earl Brunner at bruec@ANV.NET wrote:
> She blew it off
> with the statement that since the commercial glaze company said that it
> was safe it must be. I think that she is assuming a lot. Or am I being
> unnecessarily cautious? Since this lady teaches High School Ceramics
> I'm a little concerned. Any comments? I know that without knowing the
> glaze or the company that any discussion has to be limited. What are
> the liability issues with using commercial glazes? Do we just assume
> that if they say it is safe that it is?
Hi Earl,
In my limited probing of commercial glazes I find that companies have highly
variable standards for what they call "food safe". For example Spectrum
leach tests and submits their results to a toxicologist at Duke University
for an opinion. They are the most careful I have found. Next in line is
probably Opulence who has their glaze formulations approved by a well known
glaze consultant--no not ours--there are another one or two that are pretty
well known who are not Clayart members.
At the other end of the spectrum I have found commercial glazes labeled food
safe that are so unstable I use them for my lemon juice demonstration. You
can suck the color right out of them in less than an hour with a juicy slice
of lemon. Now I suppose that still may be food safe depending on what is
actually in the glaze, but these are certainly not durable glazes that are
suitable for functional work--one of the worst was obviously colored with
cobalt.
So I think you have to ask some tough questions of the manufacturers. Ask
what level of testing they do. Whether or not they use barium or lead or
cadmium. Whether they are willing to make public their test results. If you
don't get satisfactory answers, don't buy. By the way, Spectrum told me
they would tell you their test results if you were interested. I've never
tested that, but the conversations I had with the owner and his son left me
with the feeling they are a very professional and honorable company.
Opulence was the only one I saw who had lemon slices on some of their own
glazes the morning after I gave my talk at NCECA last March. That's
confidence in your product!
Regards,
John
And, believe me, they disclaim liability for getting up in the morning.
Their disclaimer statements attempt to put the liability straight on the
user.
Web sites: http://www.masteringglazes.com and 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.
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