Bruce Girrell on tue 25 nov 03
At long, long last, Lynne and I are once again in the firing business after
most of a year off to build a kiln shed and a new kiln. It's an 18 cu ft
Stak-O-Brix, based on the MFT, but built as an updraft and with a front door
that can be popped open quickly for raku usage. Nine inches IFB all around
except the door, which is three inches of refractory ceramic fiber. Two
Ransome B3 venturi burners firing from the bottom rear toward the front
along the side walls.
First firing, a bisque to ^08. Ten cone packs. Six had 08 down flat with 07
straight up. Seventh had 08 at 2:30. One, by the flame trough, had 06 down
flat. One by the center of the back wall, first shelf, had 010 down and a
second by the center of the back wall, second shelf, did not reach 010.
Overall, not bad for the first try. We'll see what we can do about that cold
spot.
The Ransomes are great burners. Much quieter than the MR100 burner with a
nicely formed, long flame and much better turndown ratio. The Ransome
piggyback pilots handle the preheat and the initial temperature ramp before
the big boys kick in.
Second firing was a horsehair raku fire. We had some adjusting to do to get
used to the new size. Our old kiln was about 7 cu ft with a front door of 22
1/2 x 22 1/2 inches. This one has twice as much area on the door so when it
is opened you really get a good face full of heat. The bigger size gives the
kiln much more inertia, too. Although it takes longer to bring a load up to
temperature, it was more stable once it hit the proper temperature. At first
we were pulling when the pots were too cool. Once we let the temperature
come up the pots behaved much better during the decoration. Lost one pot for
no apparent reason. Can't complain.
Handling hot pots and decorating inside an enclosure was a first for us.
Still some improvements to be made in the work flow but, again, not bad for
the first round. The kiln shed is built with two large (8' wide) doors, one
that is a slider and one that swings open. The doors will allow us to work
in the open when weather permits, but inside when it is windy and/or cold.
As far as the construction of the shed goes, don't look for me to be
extolling the virtues of steel framing any time in the near future.
Everything about it is more difficult and time consuming than wood frame
construction. Its only redeeming feature is that it is completely fireproof.
Anyway, we're happy to be making pots again. We'll try to get the
temperature leveled out a little, then go for ^10.
Bruce "burn, baby, burn" Girrell
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