Monday, October 11, 2010

KILN OPENING FOR HIGHFIRE GAS REDUCTION 10.11.2010

Lee College Ceramics, Baytown Texas
Prof. Jen Herzberg


DJ Brewer writes:
We had the best firing ever this time -- just awesome reduction.  The colors were spectacular -- we even good some good carbon trapping going on.  Phil's ash glazes were super.  I got an AWESOME piece with Hank Murrow's shino recipe that uses low melt spodumene and Helmer kaolin.  I'll add shots until they are all up.  Right now I'm putting up the ones of the Kiln Opening, front shelves and back shelves




Jen called me as soon as I arrived for the kiln opening to ask me about what glaze I used on a bowl that came out beautifully.

I told her it was Hank Murrow's shino. It flashed and blushed and carbon trapped -- it was amazing coloration from just one glaze






Amazing! I'm going to mix up some more of it.  I think I used the smooth shino recipe, but I'm going to mix up some of both of the recipes below for the next highfire.

Two of the ingredients are hard to find -- lowmelt spodumene and Helmer Kaolin.
You can get low melt spodumene (also called montebrasite ) from http://www.igctechnologies.com/
You can get Helmer kaolin from Wendt Pottery
http://www.wendtpottery.com/helmer2.htm

You can also use McNamee kaolin, but I did not get any of that.

Here is the recipe that Hank Murrow emailed me a long while back

Cryolite........................................ 0.6 %
Nepheline Syenite........................ 55.4
Low-Melt Spodumene................. 18.0
McNamee Kaolin........................ 26.0
100.0 %
Add: Veegum T.......................... 1.0 %
0.159 K2O 1.593 Al2O3 5.246 SiO2
0.534 Na2O 0.006 Fe2O3 0.023 TiO2
0.041 CaO 0.067 P2O5 0 . 0 0 0
MnO2
0.010 MgO 0.101 F
0.256 Li2O
White where thick; red where thin.
Best with early reduction firing with a long
concluding period of oxidation, or a soak
in oxidation during cooling. Yields a very
soft and fat surface with crawling. Crawls
more strongly if fired soon after glazing.
Note the low (3.3:1) silica to alumina
ratio. Cryolite seems to deepen the color.
Perhaps while outgassing, the fluorine content
carries iron from the clay to the glaze
surface. Low-melt spodumene contributes
phosphorus, which (as in Shaner’s Red)
also helps the fire color. McNamee kaolin
is a Georgia clay having a lovely blush of
color in the wood fire, probably because
of its iron/titanium content, which is also
beneficial in Shinos; Helmer kaolin can
be substituted.


Hank’s Smooth Shino Glaze
(Cone 10, reduction then oxidation)
Cryolite........................................ 0.8 %
Custer Feldspar............................ 32.2
Nepheline Syenite........................ 35.0
Low-Melt Spodumene................. 18.0
McNamee Kaolin........................ 13.0
Silica............................................ 1.0
100.0 %
Add: Veegum T.......................... 1.0 %
0.287 K2O 1.292 Al2O3 5.484 SiO2
0.428 Na2O 0.005 Fe2O3 0.011 TiO2
0.034 CaO 0.064 P2O5 0 . 0 0 0
MnO2
0.006 MgO 0.129 F
0.245 Li2O
A white satin where thick; red where thin.
Best with early reduction and a long,
concluding period of oxidation, or an
oxidation soak during cooling. Produces
iridescence with oxides.

I sent Hank the images and he said that he thought it was the Smooth shino recipe -- that's what I recall also.  He said he'd never seen it carbon trap -- but it did on a tiny teabowl I made in the spring.  I'll have to get a photo of that up also.

Phil's Woodash Menagerie!

Phil's got it down. He made glaze of 50 percent wood ash with cobalt in the blueish ones and copper in the green ones and the brown ones had no colorant added. The glazes don't dribble down on the kiln shelves any more.  He sprays 2 coats on the base, four on the middle, and 6 on the top.

Phil de man!


More goodies on the table


Pleased potters parlay over pieces.



Nice Teadust and bright copper reds


Lizard Brush Holder



Newborn Baby Cyclops covered in Monster Snot and drool


I'll post more later.....

It's been a long day.

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