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#21 Kohaku

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Posted 19 November 2013 - 11:34 AM

 

I'd think that the issues you'd encounter with a Japanese bowl (porosity, thermal transference) would be similar in a western-style raku vessel... assuming, of course, that there was nothing toxic in the glaze.


I've related this story before about a "food safe" non-toxic labeled product from one major manufacturer that I was wanting to use.  I called to talk to their tech support folks to get an answer about any lead being in the product, since I make food wares and the FDA laws require that I know about that potential fact..  I got told by the people I first got sent to ... nope... none in there.  But from talking to them and asking questions, I became well aware that I knew well more about technical ceramics than they did.  These were their "tech support staff" that 99% of potters calling them would get.  I kept asking for someone further up the technical "food chain".  After a few layers and people who clearly could not answer a real techniocal enquiry, I finally asked them if they had a ceramic engineer type person on their staff.  They said they did.  I asked to talk to him.  In about 1 minute or less I had my answer.  Yup... lead in there.  Those products are still sold by that company as "food safe".

 

 

Incredibly disturbing.

 

It also jibes with my experience trying to track down similar information at another company. I was shuttled through about five layers of reps and technicians, and they finally referred me to an 'external expert' (basically another potter who used the glazes). I walked away no better informed than when I started.

 

It would boggle my mind that a company develop a cadmium based glaze (or lead) even in a frit, and call their product 'food-safe'... But that story of yours makes it clear that all assumptions are unwise here. I guess I'd better- at minimum- send this information to the customer and get his acknowledgement that he understands.


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#22 Cass

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Posted 19 November 2013 - 01:34 PM

been selling raku tea bowls for 20 years, always non-toxic, etc...i see them first for the form, not the function.  i give each buyer the full spiel on decorative vs. use, how the luster will be lost, and basically tell them not to use it.  i also have a card that goes with each piece that re-explains the whole thing.  giving all the facts i lose no sleep over it, grown-ups can make their own choice, and i know some have probably been used.  i use them myself /

 

 



#23 oldlady

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Posted 19 November 2013 - 04:47 PM

funny thing, john.  i said some of this earlier this year and was rak(u)ed over the coals for weeks by people who did not want to hear it.  you say it and it must be true.


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#24 Kohaku

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Posted 19 November 2013 - 05:30 PM

funny thing, john.  i said some of this earlier this year and was rak(u)ed over the coals for weeks by people who did not want to hear it.  you say it and it must be true.

 

What? The varlets! Show me these rogues...

 

<momentary, uneasy shifting of feet?

 

I wasn't one of them, was I?


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#25 Babs

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Posted 20 November 2013 - 03:09 AM

If you were to write with a sharpie on the bottom of pot that one of the glazes used contains cadmium or lead, would your customer still want them as drinking vessels? Would the same person buy food products containing these known toxins? The 'label' should go with the pot. We have rid ourselves of lead rainwater pipes, need to be responsible.



#26 JBaymore

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Posted 20 November 2013 - 10:54 AM

Legally the exact way that lead and cadmium bearing "not food safe" wares are required to be identified is stated in the US by the FDA laws. It requires fired on labeling and even specifies the fonts and size. This is because the pieces can change hands multiple times in their life, and things like verbal instructions, hang tags, and the like go "bye-bye". And unfired writing and stickers fade with time.

 

best,

 

.................john


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#27 Kohaku

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Posted 20 November 2013 - 12:11 PM

Legally the exact way that lead and cadmium bearing "not food safe" wares are required to be identified is stated in the US by the FDA laws. It requires fired on labeling and even specifies the fonts and size. This is because the pieces can change hands multiple times in their life, and things like verbal instructions, hang tags, and the like go "bye-bye". And unfired writing and stickers fade with time.

 

best,

 

.................john

 

John- my understanding is that a glaze can contain lead or cadmium and still be labeled 'food safe' as long as it's been leach tested. Of course, that leach testing assumes specific firing conditions.

 

I'm curious, though, as to what the legal responsibility of the potter would be if they used a 'food safe' glaze that contained lead or cadmium... and their firing process resulted in higher rates of leaching than seen with the original tests. Would they be 'covered' by the manufacturers claim... or would they bear culpability for not testing the function of the glaze under their personal firing conditions?

 

(Let me emphasize, I'm NOT considering marketing a raku dinnerware line... but I'm intrigued by the legal complexities here...)


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#28 JBaymore

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Posted 21 November 2013 - 11:15 AM

I'm curious, though, as to what the legal responsibility of the potter would be if they used a 'food safe' glaze that contained lead or cadmium... and their firing process resulted in higher rates of leaching than seen with the original tests. Would they be 'covered' by the manufacturers claim... or would they bear culpability for not testing the function of the glaze under their personal firing conditions?

 

I addressed this exact issue a bit in another thread recently... that lead to a "blow up" with one forum member....... who apparently felt I was "discouraging" people. Can't remember where it was..... I'll look around and put a link here soon. Short answer..... YOU are responsible.

 

best,

 

................john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

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#29 JBaymore

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Posted 21 November 2013 - 11:21 AM

Found it. Here you go: http://community.cer...glazes/?p=45892

 

best,

 

................john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#30 Kohaku

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Posted 21 November 2013 - 04:22 PM

Found it. Here you go: http://community.cer...glazes/?p=45892

 

best,

 

................john

 

Very clear- thanks.


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