SUSAN MCNELEY on tue 6 aug 96
This is my first post, but I've learned a lot from listening to all of your
discussions. Thanks. I am glazing sourdough pots with the following white
glaze and wonder if any of you know if there might be a health concern as
far as the sourdough reacting with the glaze over time? Thanks for the help.
Sue
Dolomite 2.1
Gerstley Borate 21.3
Whiting 10.6
Custer Feldspar 27.7
EPK 6.4
Flint 31.9
Zinc Oxide 3.2
Bentonite 2.1
Zircopax 5.0
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Ron Roy on wed 7 aug 96
Hi Susan,
When I use the limit formulas from Insight it's OK at cone 6 - anything
above that gets iffy.
When I use the limit formulas from Green and Cooper with B2O3 included with
the fluxes it's short of Al2O3 so you might want to try the following
revisions which will satisfy both sets. You must test first though because
when Alumina is added to glazes with Boron you can get more melting than
you expect.
Revision #1: Increase EPK to 16. The expansion/contraction is getting low
however so test for that.
Revision #2 Custer up to 40, EPK up to 12 and Silica down to 26. I don't
expect a problem with the expansion on this one.
You did not say what cone you fire to - I am assuming cone 6.
Let me know what happens please.
I don't expect there would be a problem with the original because there are
hazards incorporated - What else do you use with this glaze?
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
Ron Roy on thu 8 aug 96
Re my answer to Susan about her glaze:
Upon re-reading it I noticed an error
" I don't expect there would be a problem with the original because there are
hazards incorporated" should read - I don't expect there would be a problem
with the original because there are NO hazards incorporated - What else do
you use with this glaze?
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
SUSAN MCNELEY on fri 9 aug 96
At 09:10 AM 8/8/96 EDT, you wrote:
>----------------------------Original message----------------------------
>Re my answer to Susan about her glaze:
>
>Upon re-reading it I noticed an error
>
>" I don't expect there would be a problem with the original because there are
>hazards incorporated" should read - I don't expect there would be a problem
>with the original because there are NO hazards incorporated - What else do
>you use with this glaze?
>
>
>Ron Roy
>Toronto, Canada
>Evenings, call 416 439 2621
>Fax, 416 438 7849
Ron, I use this glaze on all my functional pottery pieces. Using it with
sourdough concerns me because of the residual smell of sourdough left in the
container after it has been in there for several months. That's why I
wonder if the sourdough is reacting with the glaze. I do fire to cone 6.
Thanks for the suggestions for the two revisions. I will try them. Thanks
--Sue
--
Registered ICC User
check out http://www.usefulware.com/~jfoltz
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