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[Enamel Bits] Toxicity of enamels


#1

Some jewellery enamels contain toxic oxides and lead. After they
have been fired in the kiln are they still toxic?

Richard Whitehouse
http://home.clara.net/rw/
UK

Email: @Richard_Whitehouse1


#2

I have always been told that once fired to a smooth surface they
are entirely non toxic. Like asbestos or lead based paint, the
problematic chemical contained within enamels is only dangerous
when the enamel is a powder and can become airborne or the lead
is free to be absorbed by touch.

Karen

@karenworks1


#3
Some jewellery enamels contain toxic oxides and lead. After they
have been fired in the kiln are they still toxic? 

G’day Richard, Since fired enamels are a form of glass, I
would say you’d have to work hard at it - like eating them with
acid - before you’d get poisoned. Cheers,

       / \
     /  /
   /  /
 /  /__| \      @John_Burgess2
(______ )       

At sunny Nelson NZ (in late winter)


#4

I understood that the problem of toxic elements, particularly
lead, in fired enamels was that with the use of anything acidic,
like orange juice, the lead could leach out into the juice.
This is the same problem that sometimes occured with pottery
jugs before glazes went lead-free. Thompson Enamels always
advised that enameled pieces shouldn’t be used for food or
drink. I don’t know if this still applies with the lead-free
series.

Donna Wilson in WY


#5
   I have always been told that once fired to a smooth surface
they are entirely non toxic.  Like asbestos or lead based
paint, the problematic chemical contained within enamels is
only dangerous when the enamel is a powder and can become
airborne or the lead is free to be absorbed by touch. 

Mostly that’s true. The exception would be enamelware that’s
designed for food use, or other environments where there may be
exposure to acidic environments. These (such as fruit juice,
etc.) can leach the lead content back out of the glass (enamel).
Same is true of lead based colors in ceramic glazes. It’s
prehaps helpful to remember that while lead lowers the fusing
temp of the enamel, as well as increasing the refractive index of
the glass, thus making the enamel more “brilliant” and glassy, it
ALSO lowers the hardness and durability of that enamel. Recall
how fine leaded crystal will etch some when washed with harsher
dishwasher detergents, while ordinary glass will not do so as
easily…

Hope this helps.

Peter Rowe