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understanding glaze and heat dynamics petition for ron roy

updated fri 8 apr 05

 

sincultura13 on mon 4 apr 05


"I am tempted to say - you can avoid all that by not using know toxic
materials in your liner glaze. The trouble with that advice is the
lack of real thought that most potters have about what is toxic and
what is not."

RR"


EXACTLY!!! I have received wonderful advice on glaze safety here and
elsewhere but I'm still worried about what to use since everybody
seems to have a slightly different understanding what is or not
toxic=85 Could you please, please point me to a website with the
complete list of materials you think are safe for liner glazes that
aren't going to be tested for leaching in a lab?

Sincultura






--- In clayart@yahoogroups.com, Ron Roy wrote:
> We should keep in mind that all glazes leach - it is a matter of
how much
> and under what conditions.
>
> The lemon test only shows up very unstable glazes - if you want to
know if
> your glazes are stable have them lab tested and apply the
standards you
> think are appropriate and/or that are imposed by law.
>
> I am tempted to say - you can avoid all that by not using know
toxic
> materials in your liner glaze. The trouble with that advice is the
lack of
> real thought that most potters have about what is toxic and what
is not.
>
> RR
>
>
> >Once you start doing this you can use the lemon or
> >lime test method Ron and Jon has explained to see if
> >leaching occurs. Bases need to be checked for a myriad
> >of things to ensure a good start and any addition of
> >color needs to be re-calculated for performance.
> >There's lots of dynamics at play between the weights
> >of specific colorants added to various bases. What you
> >done was allot of work but you learn valuable
> >experience from those efforts. Keep doing it and
> >learning!
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
>
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Ron Roy on wed 6 apr 05


Hi Sincultura

Your best reference will be Monona's book - you can read about the know
toxicity of just about all the materials we use and decide for yourself
which to avoid in liner glazes.

The Artists Complete Health and Safety Guide by Monona Rossol
ISBN 1-58115-204-3

There are lots of absolutely safe materials for us to use - and many that
just require some basic knowledge to incorporate properly in our ware.

Keep in mind that lead and cadmium are regulated everywhere and testing for
those would not be cost effective for studio potters.

In Austria Zinc, Antimony and Barium are regulated.
In Finland Chrome and Nickel are regulated.
In Hungary all other metals are regulated but at a relatively high level.
In Korea Arsenic is regulated.
In New Zealand Arsenic and Antimony are regulated.
In Slovenia Chrome, Barium, Selenium and Antimony are regulated.

I recommend that if you do use toxic materials in a liner glaze that you
have the glaze tested from time to time to see just how much of a
particular poison can leach into food.

RR


>EXACTLY!!! I have received wonderful advice on glaze safety here and
>elsewhere but I'm still worried about what to use since everybody
>seems to have a slightly different understanding what is or not
>toxic=85 Could you please, please point me to a website with the
>complete list of materials you think are safe for liner glazes that
>aren't going to be tested for leaching in a lab?
>
>Sincultura

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
=46ax: 613-475-3513=20

sincultura13 on thu 7 apr 05


Ron Roy wrote:

"Your best reference will be Monona's book - you can read about the know
toxicity of just about all the materials we use and decide for yourself
which to avoid in liner glazes.

The Artists Complete Health and Safety Guide by Monona Rossol
ISBN 1-58115-204-3"

Thanks. If I can't find a copy at the library, I'll hit the web for a
second hand copy...

BTW, Lee Love sent me a link to an article on leaching which has a
partial of safe materials... The site also has links for low, mid and
high fire glaze bases. Very informative for newbies like me.

here's the link:

http://ceramic-materials.com/cermat/education/12.html



Sincultura