Waterfall Brown Is Not Food Safe!

[Deb Evans]

I keep telling some home schooled potters that waterfall brown from Mastering ^ 6 Glazes as stated in the book - IS NOT FOOD SAFE. They persist in using it in interiors of fuctional ware. They did ask local clay supplier if it was food safe and he assured them it was. UGGGGGG! How do I get through to these people? Need some suggestions - these folks are the kind of people that cry when you critize their ware, firing methods, etc...

 

 

[Pam S]

Have you shown them the book? You know from the horses mouth so to speak. If the developer of the glaze states it's not food safe, I'd certainly take that to the bank.

[Brandee Ross]

Deb, I also understood Waterfall Brown to be food safe based on the following from Mastering Cone 6 Glazes (page 106, fifth printing):

 

"Again, this is a specialty glaze that is quite stable in its own right, but the base glaze does not meet our copper leaching criteria. It does, however, pass our more rigorous dishwasher test so it should be a good glaze to use on dinnerware."

 

To me, that implies that the base glaze components may not be suitable when used with other colorants. Furthermore, the authors detail in their introduction that when they refer to glazes as "durable" or "stable" that the recipe contains materials that could cause concern if significant amounts leach, but that their tests have shown the glazes to be on the stable end of the spectrum (and sometimes leaching less than commercially available "food safe" labeled glazes).

 

Can you please explain why it is not food safe? I am not trying to be combative, merely curious as this is a glaze I sometimes use in conjunction with others in my arsenal.