Martha Muzychka on tue 16 apr 96
Hello,
I am interested in knowing what the safety consideration are for lithium
carbonate in glazes. I have read a lot about barium carbonate in glazes,
and how they shouldn't be used for items you want to be food safe. Do the
same considerations apply with lithcarb? Are lower amounts (less than 10
per cent) better than higher amounts (greater than 10 per cent)?
Also my studio partner is looking for a bright white glaze (opaque)
suitable for Cone 6. We have tried a few from the glaze base but they are
more creamy ivory than white. We tried the DK11 Revised recipe but it
looked a little crawly.
Finally, I deleted the digest with the information about the ORTON cones.
Could some one send me the information about what to ask for. We are still
having some problems with glazes not firing properly with the new cones.
I would like to retest with an old cone formula and again with the new
cone to see what's going on. In the last glaze firing, a previously
stable glaze has begun to pinhole and there's been no change in the clay
batch we've been using.
Thanks for your help. I will try and post the results of my glaze tests
as soon as I can -- lots of really interesting effects.
Martha Muzychka
Jo Ann Stevens on wed 17 apr 96
Martha
Here are 2 glazes you might want to try. I tested both of them with 10%
superpax and they turned out too white for me.
----------------------------------------------------------------------------
-----------
MIDNIGHT BLUE cones5-6-7-8 Cooper, pg. 105 opague
Feldspar 44
Whiting 17
Ball clay 8
China Clay 9
Flint 22
Cobalt 5% for rich midnight blue
Superpax 10% for bright white--very good colour response with on glaze
stains.
----------------------------------------------------------------------------
-----------
FRIT 25 5 -6-7 Conrad, pg. 165 transparent, gloss clear
Potash feldspar 34.9
Frit #25 25.3 used frit 3269
Flint 25.3
Whiting 5.8
Gerstley borate 5.1
Kentucky ball 3.6
apply thin,
I added 5% more flint---see text for colour options.
Superpax 10%--really bright white--good colour response with stains except pinks
Hope these are of use to you.
Jo Ann Stevens, St. Catharines, Ontario. Canada.
>----------------------------Original message----------------------------
>Hello,
>I am interested in knowing what the safety consideration are for lithium
>carbonate in glazes. I have read a lot about barium carbonate in glazes,
>and how they shouldn't be used for items you want to be food safe. Do the
>same considerations apply with lithcarb? Are lower amounts (less than 10
>per cent) better than higher amounts (greater than 10 per cent)?
>
>Also my studio partner is looking for a bright white glaze (opaque)
>suitable for Cone 6. We have tried a few from the glaze base but they are
>more creamy ivory than white. We tried the DK11 Revised recipe but it
>looked a little crawly.
>
>Finally, I deleted the digest with the information about the ORTON cones.
>Could some one send me the information about what to ask for. We are still
>having some problems with glazes not firing properly with the new cones.
>I would like to retest with an old cone formula and again with the new
>cone to see what's going on. In the last glaze firing, a previously
>stable glaze has begun to pinhole and there's been no change in the clay
>batch we've been using.
>
>Thanks for your help. I will try and post the results of my glaze tests
>as soon as I can -- lots of really interesting effects.
>
>Martha Muzychka
>
>
**************************************************
* *
* Too much of a good thing *
* can be wonderful! *
* *
**************************************************
jstevens@niagara.com
| |
|
