Sam Cuttell on sun 9 mar 97
The following are glazes I have taken from Clayart and
fired to ^10 ox on Plainsman H550 clay (old batch).
I fired at 50% over night, up to 75% in the morning for
4 hours, then high till ^10 was almost touching. No
soak. Kiln kept closed tight for 16 hours - then
unloaded (I think that covers everything). Oh, and
^11 in sitter.
Please note that comments are _my_ observations of the
tests and as such, are very subjective.
Many thanks to those that submitted these glazes to the
group at large!!
35 Custer Spart
White satin opaque glaze. Nice texture. Crazed like mad.
Nagamoto Teat (redux)
52 G-200 (it just said feldspar, so I picked one!)
21 Barium Carb (I subbed 15.75 Strontium)
8 Zinc Oxide
3 Copper Carb
Ran off pot where thick. Open crystalline areas (read non-functional
surface). Matte black breaking to pale green where thin.
^6-7 Red/Pink ox or red
Now maybe I should have noted the 6-7 part before firing (duh)
21 Gerstley Borate
16 Neph Sy
5 Tin oxide
.15 Chrome ox
Of course, it ran (thumping forehead with heel of hand). BUT!! got
pink/red where it pooled!!! Can one of the glaze gurus please reformulate
for ^10 for me? I would be most appreciative!!!!!
Peacock Blue 9-10
45.45 Neph Sy
.5 Cobalt Carb (I have silicate)
4 Milled Illmenite
Ran right off the test tile! To me, looks like a rutile redux
blue (which I adore!). Breaks tan. Gloss. No overlap marks.
However, the tile is *still* singing to me 12 hours after
Iron Blue Water 9-10
17 Ball Clay
.5 Cobalt Carb (sil)
2 Iron Chromate (ite?)
Gloss. No runs. Deep olive green. Overlaps are very forgiving.
No depth to the glaze.
Despite being in hottest part of the kiln, looks underfired. Lots
of pitting. Off-white. *Almost* completely matte. Way too dry
for functional IMHO.
28.1 Gerstley Borate
Exactly as described - lovely oatmeal. No glaze movement. Cream/tan
with specks. Satin gloss. Does not show overlaps. Can't wait to
make up a big batch of this glaze!!
I of Toad (green textured matte)
40 F-4 Spar
1 Cobalt ox
1 Chrome ox
1 Granular rutile
"Sang" to me as I unloaded - and for several hours afterwards.
Deep turquoise green satin. Very opaque. No texture - but some
pitting. Might be useful for sculpture.
Waxy Turquoise Green ox or redux 10
11.88 Gerstley Borate
.5 Chrome ox
.5 cobalt ox
(Applied a bit on the thick side). No running. Exactly as described -
satin finish. Intense opaque colour. Ugly green where thin. This
glaze sings for hours!!
E. Henderson Teal Blue Green Turquoise
39.05 Pot Spar
5.79 Gerstley Borate
2.36 Mag. Carb
1.13 Zinc ox
.5 Cobalt ox
.5 Chrome ox
Similar to "Floating Blue". Blue-turquoise mottled gloss. Quite
beautiful. Overlaps don't show. No runs. Great opaque coverage.
Nice depth to glaze. Will do a small bucket and try marketing
some pieces with this glaze!
3.3 Chrome ox
1.1 Cobalt ox
"Must be fire hot!"
Green-teal medium gloss. Better where thicker. Very
intense colour - but no depth.
So folks, there you have it. Hope these comments are helpful.
Right now, my wrists need a break!!!
sam - alias the cat lady
Melbourne, Ontario, CANADA
Look for me at NCECA - I should be easy to spot. I wear long,
and, oh yeah; I have purple hair.
June Perry on mon 10 mar 97
Thanks for posting you glaze test results. I used the Temple White for years
in cone 10 reduction. It worked best for me Cone 10 around 3 to 5 O'clock. It
crazed on porcelain and I got delayed crazing on my stoneware body at the
time "Rod's Bod".
At the temperature I fired it was a nice looking satin matt.
You may want to try making another batch and subbing dolomite for the whiting
and using a very fine mesh silica or amorphous silica. By loweringthe calcium
and upping the magnesium and changing the silica you can slightly alter the
co-efficient of expansion and maybe ease the crazing a bit. Sometimes adding
2% lithium carbonate helps a bit as well.
Cobalt1994@aol.com on tue 11 mar 97
Another possible source of crazing in Temple White is applying it too thick.
I decided to thicken my glaze coat recently and experienced crazing for the
first time. I've gone back to glazing thinner.
Jennifer in Vermont
Thistle Hill Pottery