Food Safe?

cherylka · Post by **cherylka** » Sun Dec 07, 2003 3:06 pm

I have been using my Skutt ceramic kiln to fire my glass. I also fire ceramics in it.

I just heard from a ceramic artist who has started fusing that the glass emits gasses that make ceramics fired in the same kiln no longer food safe.

Does anyone know if this is true? Is there any documentation about it?

Thanks.
c

Kitty · Post by **Kitty** » Sun Dec 07, 2003 3:29 pm

i think it could be the other way around, with glazes contributing elements which could bind onto the glass. dont know anything about glass gassing toxic stuff that binds onto ceramics.

Tom White · Post by **Tom White** » Sun Dec 07, 2003 4:49 pm

I would have to see some serious scientific evidence to substantiate this claim before I could give it credence. Food safety in fired ceramics centers around lead and other heavy metal release from fired ceramic glaze as defined by very specific ASTM standardized tests. I cannot imagine glass in the kiln at fusing temperatures emitting enough of these materials to contaminate the kiln interior to the point that they could affect later ceramic glaze firings at higher temperatures. Perhaps Mary Kay from Bulleseye or Patti from Spectrum could provide definitive information on this subject.

Best wishes,
Tom in Texas

Tony Serviente · Post by **Tony Serviente** » Sun Dec 07, 2003 10:47 pm

I'm with Tom. Never heard of this, and we aren't anywhere near the point where glass vaporizes in kilns. Yes, it can get runny, but it isn't boiling.

rosanna gusler · Post by **rosanna gusler** » Mon Dec 08, 2003 7:21 am

bogus. i would like to know where she got that misinformation. rosanna

Kevin Midgley · Post by **Kevin Midgley** » Mon Dec 08, 2003 11:45 am

The rumour about kilns contaminating work arose probably out of the story that was heard maybe five years ago. A pottery studio in the US had their pottery tested for lead etc. and they failed. They were using lead free materials in their work so the lead etc was obviously coming from the old kilns that they were using which had previously been used for firing lead etc. glazes etc.
For that reason, people should be cautious about using old kilns that they nothing of the history of their usage.
I use a separate kiln for doing enamel/colour work and use it only for items that are not for food usage such as panels.
Some people might debate the dangers I speak of, but I would not like my glass to be the pottery studio mentioned above, and doing a product recall sometime in the future when testing becomes parts per gazillion.
Kevin