Reg Wearley on thu 3 aug 00
Thanks Ron,
Since we do nonfunctional pottery I feel that
we may have a little more latitude in our glaze
formulation than do most others. Many times it
is hard to know just where to draw the line-I
know of potters who are still using lead glazes
on their nonfunctionals and I guess I am alright
with that. No doubt you have an opinion here-
where do you draw the line on 'toxicity', if
you draw a line at all? --Reg
--- Ron Roy wrote:
> Hi Reg,
>
> You are right - Ron says don't use it where it
> can come in contact with
> food - it's short of silica and the copper is
> going to make it worse. I'll
> bet I can make it change colour with some
> foods.
>
> Even if you sub in Strontium - it may still
> change colour under some
> circumstances.
>
> Just so you all know - RR
>
> Cone 6 Barium Blue
>
> >Another glaze that we do use a lot is an
> >Amy's Blue. It is a washed denium blue and
> >is a great semi-matt. It does have a lot of
> >Barium however, so Ron Roy would suggest you
> >work with Strontium Carb instead. We do non-
> >functionals and haven't tried the Sr yet.
> >Amy's Blue:
> >Barium Carb------18.4
> >Dolomite---------11.1
> >Whiting----------4.7
> >Nephsy Synite----28.6
> >EPK--------------7.4
> >Flint------------21.5
> >Tin Oxide--------2.8
> >Zinc Oxide-------2.8
> >Copper Carb------1
> >Add Cobalt Carb--0.35
> >
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough
> Ontario, Canada
> M1G 3N8
> Evenings 416-439-2621
> Fax 416-438-7849
>
>
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Ron Roy on sat 5 aug 00
OK Reg,
I can only speak for myself here - there is much we don't know, there are a
lot more toxins around than there ever has been. I also see many glazes
with toxins in them which don't need em. There are reasons for this - most
potters are out to lunch when it comes to understanding glazes and there
seems to be no end of rationalization to try and get around learning. I'm
trying to not be critical here - people are what they are. I do feel it is
important to see the problems for what they are and do something about it.
As long as your work cannot in anyway, be used to hold or store food then
there should be no danger.
At a workshop once some one asked me if the glaze they put on a set of
bowls - for her husband - was safe. The glaze was not safe - poor
durability and lots of Barium. I suggested we let the new puppy in the
studio drink from one of those bowls - well you can imagine the outcry.
My line is - don't use them if you don't have to. If you do use them try to
put them in as stable a glaze as possible and have them tested if they are
for food. If they are being used for non containers - make sure you
understand what they can do to you, your follow workers, pets and family.
Some of these toxins are insidious and lead is right up there. It fumes
during firings and gets everywhere.
Know your poison - have your blood levels checked - and don't assume there
is no danger.
And - don't pass on glazes with toxins in them without a warning - make
sure potters can at least make an intelligent choice.
Thanks for asking Reg - as you can see I do have strong feelings about this.
>Thanks Ron,
>Since we do nonfunctional pottery I feel that
>we may have a little more latitude in our glaze
>formulation than do most others. Many times it
>is hard to know just where to draw the line-I
>know of potters who are still using lead glazes
>on their nonfunctionals and I guess I am alright
>with that. No doubt you have an opinion here-
>where do you draw the line on 'toxicity', if
>you draw a line at all? --Reg
>--- Ron Roy wrote:
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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