Steven D. Lee on tue 1 apr 03
Early on a Sunday afternoon I decided that there was no longer
anything holding me back from attempting Raku. I had the kiln shell,
made out of hardware cloth and 1" fiber with homemade ceramic buttons
and nicrome wire keeping the fiber in place.
I had made three pieces out of raku clay from Armadillo Clay and
Supply in Austin TX. I had inheirited a bucket of clear crackle
glaze, the contents of which I still have to identify. But being a
rebel I put the equivalent of .8% copper oxide and .6% of cobalt
carbonate in it. Who knew what it would do?
I started the base with standard cinder blocks and quickly found that
I had to use almost 60 lbs of sand to level out the blocks on the
ground. (There has got to be a less time consuming way of
leveling!!!) Next came the K-23 bricks, starting from the inside to
out, I made three levels (each 2.5") with a 5" opening for the burner
in a 31.5" square. No matter how carefully I placed the brick it
always seemed that there were spaces left when I finished an entire
row. Oh, well. This isn't brain surgery!!
I then connected up my varible pressure regulator and MR100 Venturi
Burner with an orifice for 8psi propane to my 12.5 gallon propane
tank and sprayed the hose and connectors with water to make sure
there were no leaks.
I carved a place out of a couple bricks to nestle the venturi burner.
When I was done it wasn't a thing of beauty, but it would be a joy
for at least a couple hours.
I set my one 16" roudn kiln shelf on top of three bricks, the front
one acting as a flame splitter, and set my first piece in the
center. I opened up the primary air shutter all the way and made
sure the two spyholes and the top vent were open on the fiber shell
and set the burner going.
15-minutes later: I turned the burner from 1/8 open to 1/6 open
At this point I must say that I was having my doubts. I
couldn't see the flame since it was so bright outside but I could
feel the heat. I looked in and there was no indication at all that
the chamber was getting hot. Could I have done something wrong?
15-minutes later: I turned the burner from 1/6 to 1/4 and moved it
within 1" of the burner opening. Covered one spyhole.
Well, it was orange in color where the invisible flame was
striking the flame splitter brick but other than that no difference
in the kiln chamber. I did feel the heat coming from the vent and
the one open spyhole but the pottery piece inside looked the same. I
was starting to feel the first hints of apprehension.
15-minutes later: The burner was turned on 1/2. What a roar!!!! I
knew that this was producing about 90000 but/hr now and I had about
9cu. ft to heat. I guess I just have to be patient!!!
5 minutes later: Almost before I knew it the chamber became toasty
orange and the vase inside began turning an ugly kind of spotted grey.
5 minutes later: The first hint of glossyness to the surface of the
vase within. A wash of relief!!!!
5 minutes later: The gosh darned whole thing was shiny, like some
molten metal!!! Yippiii!!!!!
Turned off the burner, opened the trash can with 2" of shredded paper
inside, got the tongs, said a quick prayer and prepared to jump in my
pond if something caught fire!!!!
I lifted the fiber shell and immediately the vase turned from orange
to green as a wash of superheated air hit me in the face. I quickly
grasped the vase in my tongs and dumped in unceremoniously in the
trash can and put another 2" of shredded paper on top and closed the
lid. I took the next piece, a large plate, and put it on the kiln
shelf and put the fiber shell back on, which had by now burned a nice
circle in the green grass I put it on. (I thought that the metal
plate I brought out for this purpose looked a little green!!)
I won't go into the other two firings now, but after about 30 minutes
I removed the trash can lid and lifted my piece out and dunked it in
water. After all the soot and carbon got washed off it turned out
the ugly green I had saw when I put it in the can was replaced with a
nice golden metalic surface with hints of red copper, the inside
looking like the shell of a clam or oyster. Nice!!!!!!
With everything that could have gone wrong I still got three pieces
that looked great!!!!!!!!!!!! I am glas that that one day God did
not choose to exercise God's sense of humor!!!! They were glorious
(of course this was an emotional biased account of their quality!!)
I can't wait to do it again!!!!!!
If you would like to see the results go to :
http://www.sdpottery.com/Ceramic_Misc/New_Arrivals.htm
***************************************************
Steven D. Lee
SD Pottery - The Little Texas Potter
http:\\www.sdpottery.com
millenial_age@yahoo.com
14341 FM 112
Thrall, TX 76578
512-898-5195
***************************************************
| |
|
