Cindy Strnad on thu 25 oct 01
I've been using a glaze from Lana Wilson's book,
"Ceramics: Shape and Surface", which I like more
the more I use it. This glaze, on my brown
stoneware clay, comes out a deep, variegated
white. Reminds me of onyx only deeper. With a slow
cool, I get wee crystals that seem to float on the
surface. The dry part didn't happen for me; this
surface flows like a solidified river. It's not
glossy, but I sure wouldn't call it dry. This
glaze is as alive as any glaze I've ever used, yet
it doesn't have a problem with running off the
pots.
It's high on alumina and low on silica and it does
contain a small amount of lithium--so you know. I
could not scratch it with a nail. Have not tried
the vinegar test. Since it doesn't have a lot of
color and isn't very shiny, I'm not sure what that
will tell me, but I'll give it a shot. The only
potentially harmful ingredient would be lithium
and little of that would be available for
leaching. If I drink my tea from it and start to
feel all mellowed out, I'll let you know.
Anyway, here's the recipe. As you can see, the
expansion is quite high, but I didn't get any
detectable crazing. Maybe that's the lithium;
maybe it's because I applied it quite thinly.
Dry Sculptural Matte ^6
Lynn Render
====================================
DOLOMITE............ 20.00 18.60%
SPODUMENE........... 10.00 9.30%
NEPHELINE SYENITE... 55.00 51.16%
BALL CLAY........... 15.00 13.95%
TITANIUM DIOXIDE.... 2.50 2.33%
ZINC OXIDE.......... 5.00 4.65%
========
107.50
CaO 0.26* 6.59%
Li2O 0.06* 0.79%
MgO 0.25* 4.61%
K2O 0.07* 2.92%
Na2O 0.22* 6.19%
ZnO 0.14* 5.21%
TiO2 0.08 2.84%
Al2O3 0.46 21.19%
SiO2 1.82 49.49%
Fe2O3 0.00 0.18%
Cost/kg 0.78
Si:Al 3.96
SiB:Al 3.96
Expan 8.50
I ground up the zinc with a mortar and pestle, but
of course I still had to sieve the glaze. No
biggie--I sieve all my glazes. I used 80 mesh.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
| |
|
