Jump to content


Photo

Food Safe Glaze Database

food safe glaze

  • Please log in to reply
3 replies to this topic

#1 hershey8

hershey8

    Advanced Member

  • Members
  • PipPipPip
  • 52 posts
  • LocationMineral Bluff, Ga

Posted 26 October 2013 - 02:37 PM

Is there a food safe glaze database somewhere on the internet? I seem to only find bits and pieces, here and there.  Is my search needless? By following certain rules and leaving out known toxic glaze ingredients, wouldn't most glazes then, be food safe?  Are there general recipes that we can add colorants to that are considered safe, even if they have minute amounts of toxic ingredients in them.  It seems like some  home brew glazes would be "safe" even without lab testing. Any thoughts on this appreciated.   ja



#2 atanzey

atanzey

    -

  • Members
  • PipPipPip
  • 147 posts
  • LocationSouth-Central Pennsylvania

Posted 26 October 2013 - 05:16 PM

I think you're going to hear most everyone say that it's not quite that simple.  Glazes mixed by different people, and fired on different clays with different firing schedules may have different results.  Then when you want to vary the color in a base glaze, the colorent oxides have varying toxicities and have varying effects on the glaze stability.

 

That said, if you aquire the book 'Mastering Cone 6 Glazes' by Hesselberth & Roy, they have several base glazes that have been rigorously tested, and they consider very stable.  They do an excellent job explaining the complexity and justifying their conclusion.

 

If you do enough research, you'll get a good sense of what combinations and glaze types are more stabile, but the only way to be completely sure is to have laboratory tests performed.  The above referenced book also recommends a laboratory which performs the tests, assuming it's still accurate.

 

Alice



#3 hershey8

hershey8

    Advanced Member

  • Members
  • PipPipPip
  • 52 posts
  • LocationMineral Bluff, Ga

Posted 26 October 2013 - 08:33 PM

I think you're going to hear most everyone say that it's not quite that simple.  Glazes mixed by different people, and fired on different clays with different firing schedules may have different results.  Then when you want to vary the color in a base glaze, the colorent oxides have varying toxicities and have varying effects on the glaze stability.

 

That said, if you aquire the book 'Mastering Cone 6 Glazes' by Hesselberth & Roy, they have several base glazes that have been rigorously tested, and they consider very stable.  They do an excellent job explaining the complexity and justifying their conclusion.

 

If you do enough research, you'll get a good sense of what combinations and glaze types are more stabile, but the only way to be completely sure is to have laboratory tests performed.  The above referenced book also recommends a laboratory which performs the tests, assuming it's still accurate.

 

Alice

Thanks Alice, I'll look around and get that book! It sounds like it would be worth having.  I appreciate your response. ja



#4 JBaymore

JBaymore

    Moderator

  • Moderators
  • 2,806 posts
  • LocationWilton, NH USA

Posted 27 October 2013 - 01:51 PM

Alice has it pretty much right. It is a very complicated subject.

 

To start with, there is no legal definition of "food safe glaze".

 

And legal responsibility (at least in the USA) for a product lies with the person producing it. Unless the manufacturer of even a commerial glaze specificaly mentions that it indemnifies the end user, THEY are not directly responsible in any way for any harm caused by the use of their product on YOUR wares. If you ever got into trouble..... you'd have to defend yourself. And then take legal action against THEM to recover your losses.

 

Luckily this is not a HUGE issue. Hence you can get a $2 million product liablity insurance policy as a potter for about $500 a year.

 

Best,

 

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


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

http://www.JohnBaymore.com




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users