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Food Safe Cone 6 (5) Ox Glazes Please

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#41 JBaymore



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Posted 06 March 2014 - 11:26 AM

can some give me their opinion and or facts on  glazes with lithium.


if the chemicals are "glassed"  and aren't leaching  then shouldn't this be safe?


It is pretty simple in that black and white case you gave there, Lou.  If the glaze doesn't leach lithium (or anything else), then there is no problem at all.  The "grey area" part of the equation is answering that question........"Is the glaze leaching anything toxic into foodstuff?"


The absolute ONLY way to know that for sure is to have random (and regular) samples ascetic acid lab tested to see what is "coming out" of the glaze.  In the USA, other than for lead and cadmium, there are no other "pottery laws" that apply to the leaching of anything out of glazes.  So for everything else, the best potential "guidelines" we have are the US FDA drinking water standards for various compounds.  SInce thiose guidelines are meant for drinking water conmsumption, they are based on large quantites of daily consumption.  So they would be VERY conservative standards to use.  But they can help point you in the right direction.


Then you come to the issue of manufacturing controls.  How accurate are your processes (glaze raw materials pre-use testing, glaze mixing, glaze application, kiln firings as to firing cycles, even-ness of chamber, and so on)?  The more accurate these manufacturing controlls are (like in industry), the less often you will have to do lab testing to be sure.  This is because with good controls, that helps assure that the samples tested actually DO apply to the general production runs.


And of course you should be having documentation of all of this stuff you are doing on file "just in case".


That above being said, there are product liability laws that still do apply to potters.......... which would be tested in an individual court case if a person feels that your product has caused them harm.  If you manufacture a product, and that product injures someone in some way, and they can prove that fact in a legal setting, you are legally liable for damages. (Generally a civil situation.)  If there are things in your professional practice that relate to the safety of your product which you should have been aware about (and it can be proven that you should have been), and you can be proven to have deliberately choosen to ignore that information, then you can also be held responsible for willful negligence above the normal liability issues....... which opens up some other nasty legal headaches and potentiall punitive damage claims (usually really BIG $ above the other damages).


Now....... how often this kind of thing actually happens is pretty much reflected in the product liability insurance available for potters.  You can pick up about $2 million in coverage for such issues (and also show and premises liability) for less than $1000 a year.  In the insurance world, cheap.  THAT says that this is not a huge legal issue for potters.


We also then come down to the "morality" portion of the question.  A potter has to ask themselves if they are willing to "gamble" with the health and well being of the people who have purchased (or been given) their products.  And how much they are willing to gamble.  There are no "morality police" (at least in this country).....only one's own conscience. 


That's the best I can give you.





John Baymore
Adjunct Professor of Ceramics; New Hampshire Insitute of Art

Former Guest Professor, Wuxi Institute of Arts and Science, Yixing, China

Former President and Past President; Potters Council



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