Richard Gralnik on wed 8 sep 99
Yes, you read right. Amazing but true. After 4 years of planning,
welding, pouring,
plumbing, framing, bricklaying and tweaking, GralniKiln (Serial No. 1)
fired its first
load to bisque yesterday.
Well, actually yesterday and today. The firing started at 7AM yesterday
and ended
at 7AM today. No, I didn't have problems getting to temperature. Exactly the
opposite. Get a cup of your favorite hot brew in your favorite mug and
"Let me tell
you a tale."
You may recall my concerned post last week about my thermocouples getting
cold and prematurely shutting down the gas. Well, thanks to some advice from ]
an HVAC specialist who's brother is an old friend who lives conveniently
across
the street solved that problem. I fabricated brackets to hold the
thermocouple/pilot
assembly VERTICAL instead of my original horizontal and clamped them to my
manifold. I also replace the solid sheet metal windbreaks around the bottom of
the kiln with perforated metal ones. I painted everything with black
hi-temp BBQ
paint before setting everything up. I didn't *know* if it would work, but Pat
Allison of Allison HVAC, Gardena, California (310) 679-4643 for all your
heating,
ventillation and air conditioning needs knows his stuff, so confidence was
high.
I set the kiln Saturday night with what I thought would easily be a full
load of pots.
Wrong. As loosely packed as the kiln was, I still had a shelf and a half
of space
left. As a result, rather than candling overnight Saturday, I got on my
wheel and
threw a bunch of test tiles and some taller pots to fill up a reasonable
load. I
dried these overnight in our oven (after my wife went to bed of course) and
loaded
them in the kiln early Sunday morning.
I lit the pilot on one side of the kiln and connected my nifty digital
thermometer to
my industrial strength K thermocouple. The thermocouple glowed red hot, the
pilots lit just fine, and the temperature quickly climbed from the early
morning 63
to 130. I cracked the door and watched the temp stabilize at about 135 and
left
the kiln to candle that way for the next 10 hours while I painted my kids
playhouse
and "lawned the grass" as my 3 year old puts it.
At 5:30PM I closed the kiln door, lit the pilot on the other side of the
kiln and
started the labor that would culminate at 7AM the next morning. I must
tell you
my wife got tired of me announcing another centimeter of dialation for each 200
degF of climb long before I stopped finding the humor in it.
Those of you who have followed the saga know my precision engineered 18 cu ft
kiln has 6 MR750's being fed from a 1 1/2" diameter gas line. The burners are
positioned 3 to a side under the floor a la Geil, with the associated
arch-high
chimney. I also used a Nils Lou double-venturi flue. With all that
heatpower, I
ended up turning off the middle burner on each side, and reached 1335 degF
before *any* pressure registered on the WCP gauge. Cone 06 went down with
1718 degF showing on the digital thermometer.
An aside on those digital babies. Ok, they give A-retentive potters like me
something to watch and worry over for hours on end, figuring out the temp
climb rate after every increase in gas. But for a firing first-timer
flying solo at
night his first time out it probably saved this load of pots from turning into
ceramic shrapnel.
Some highlights from my log -
The temperature climb rate wove erratically but relatively steadily higher and
higher although there were fits and starts each time I added gas. The temp
jumped as soon as I opened the gas valve at all. I tried to maintain a
150degF/hr but bounced around it like a new bobsled driver trying to stay in
the middle of the chute but scraping the sides of the track all the way down.
I reached 1335degF with NO pressure showing on the WCP gauge. At that
point I opened the gas to 1/2" and the temperature jumped and ran. I finally
noticed the that top peep showed a much brighter color than the bottom peep
and I got very nervous about an uneven firing. Thanks to Tracy Dotson for
his help out of this jam. "Ok, it's 4:50AM. The kiln is climbing like a
rocket
and the top is hotter than the bottom. Who can I call for advice? No one in
this time zone."
At 1467degF the burners suddenly made a "FoomP" sound and got quiet.
Too quiet. I looked under the kiln expecting to see a series of extinguished
burners. Instead I saw 4 blue streams of flame being inhaled by the kiln
where moments before the flames had been yellow, nervous, and kind of
loud.
I opened the damper to 7" to try to get the lower half of the kiln to heat up
(orange bottom peep, bright orange to yellow top peep) and lowered the
gas to buy some time. No luck. The heat never evened out. The top
Cone 07 started to bend at about 6:30 and by 6:55 Cone 06 was down and
I shut off the kiln. The bottom cones never moved.
24 hours, a lot of nervousness, a lot of adrenaline and a feeling that after
all the emails, phone calls, questions, research and construction I can
finally start to think of myself as a potter. I'll learn more when I open
the kiln and again when I glaze fire for the first time, but I fired my first
load.
Richard
exhausted but proud
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