Robin Wolf on sun 21 jan 07
Well, I have the first portion of my dual fuel kiln conversion done =96 =
WOO
HOO!
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I started with a decent Cress B27H (7cu ft). I had to replace at least =
one
element, so decided to bite the bullet and go all the way for a =
conversion
while I was at it. So far, I have about 6 hours in it, but that =
includes
welding the stand to the =BD=94 steel sheet that the kiln sits on, and =
adding a
set of locking casters and handles to help in moving the kiln by myself.
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Talked to Feriz at ITC - Read for hours on Clayart =96 Read the =93Art =
of
Firing=94 again - Ordered all new elements from Euclid =96=96 Ordered =
all 4 ITC
products from Big Ceramics Store =96 Ordered a pyrometer from Axner =96 =
and then
thought about selling a kidney to help fund this! I kept thinking about =
Mel
saying don=92t be cheap. I do have a tendency to be a bit snug, so this =
was a
pretty big investment for me!
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After taking all of the old elements out, I reassessed the condition of =
my
kiln, and it slid down a bit - enough of a slide to convince me to take =
the
entire kiln apart and rebuild it. I vacuumed the kiln very well with =
the
shop vac after I took out the old elements. BEFORE I removed the =
elements,
I marked each wire and the corresponding port that they would tie to. I =
did
replace the porcelain insulators =96 only 4 of the insulators on the =
kiln were
still intact, the rest were either broken or split. Cress still had a
limited number of them, and treated me very well when I called and =
ordered
them.
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The new elements were dipped in the ITC Metal Coating =96I did this in =
the
guest room shower. I moved the shower rod to be closer to the center of =
the
shower, hoping that I would make less of a mess. I dipped the elements =
in
thinned ITC (it was about the consistency of half & half), hung them =
from
the shower rod, and gave them a good shake to get rid of the excess. =
They
hung there overnight to get good and dry. Each element was touched up =
with
a sponge brush before they were put in the kiln.
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I unstacked the 2 rings of the kiln, and started with the bottom layer. =
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Loosened up the outside skin, labeled each brick as to its position so I
knew how to replace them.=20
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Suggestion - keep a package of sturdy rubber bands at hand to hold any
cracked bricks together. =20
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I patched the floor using ITC 200 in the places where removing the kiln =
wash
left some craters. When the patches were pretty dry, I poured thinned =
ITC
100 on it, and spread a thin coat evenly across the entire floor of the =
kiln
with a soft whisk broom. I coated the burner port with the ITC 200 to =
help
protect it from the flame.
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I washed each brick individually with a Scotch Brite scrubber on the =
sides,
and a baby bottle brush for the grooves. =20
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An old Tupperware bread keeper worked perfect to put the thinned ITC 100 =
in
for dipping the individual bricks. I had a small hand blender that I
whizzed the ITC with EACH TIME before I dipped a brick. The ITC settled =
out
very quickly, so it had to be stirred very well right up until you dip =
the
brick in it. Dipping the brick face down makes sure that you get the =
best
of the ITC on the working side of the brick. I patched the broken spots =
on
the bricks after they were dipped, and then replaced the bricks in their
original place in the kiln. =20
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I replaced the bottom skin and tightened it up. To help tighten up the
skin, I used a pair of vice-grips to help bring the skin together so =
that
the bolts did not strip out. Then the elements went back in =96 pinning =
the
corners after each element was in. =20
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When I removed the skin from the upper portion of the kiln, the metal =
plates
that helped support the lid hinges were rusty masses of nothing solid. =
The
screws that held the hinges on had degenerated to rusty spikes the size =
of a
pencil lead. This was one of the main reasons that I decided to strip =
out
all of the bricks and dip them instead of just spraying them. I had to =
at
least loosen up the skin to get the hinge problem taken care of, so just =
as
well go all the way!
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To reinforce the hinge attachment area, I had a friend cut me a strap of =
10
gauge stainless steel that was about 2 inches longer than the distance =
that
I needed to cover, and the same width as the hinge strap. We drilled =
holes
in the reinforcing strap to match the mounting holes on the hinge =
straps.
The new piece of stainless was placed between the kiln skin and the =
bricks
with the original hinge on the outside of the kiln skin. Stainless =
steel
carriage bolts were used to attach everything. The head of the carriage
bolt goes toward the bricks, with the nuts on the outside of the kiln. =
Just
in case, the reinforcing strap and the head of the carriage bolt were =
coated
with ITC metal coating.
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The upper portion of the kiln is 4 layers tall, and it did concern me =
about
just stacking the bricks back up before the skin was replaced. To =
stabilize
the bricks after stacking I used bungee cords to wrap around each layer =
to
help hold it steady until the skin could be replaced.=20
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Once the skin was back on, I replaced the elements, polished and trimmed =
the
ends on all of them, and wired every thing back up.=20
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MAKE NOTE - I replaced all of the screws with stainless steel screws, =
bolts
and nuts. They should be more resistant to the elements that the kiln =
has
around it. Stainless Steel is more expensive, but I think that the =
added
life and safety issues (hinges/handles) are well worth it.=20
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I washed the inside of the lid, patched the few little spots in it, =
coated
the flue hole with the ITC 200, then coated the lid face with a thin =
coat
of ITC 100.
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At this point, I have a small ceramic heater inside the kiln, just =
gently
drying it overnight before I plug it in tomorrow morning to do the =
initial
firing.
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I still have the second coating of ITC 100 to spray on, refire, and the =
ITC
Top Coat and the final firing. I plan to have this ready to fire by =
next
weekend - hopefully!
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Thanks to Nils, Mel and Feriz - I=92ll keep you posted with the progress =
and
results of my dual fuel kiln. If you see anything that I have screwed =
up on
this little project so far =96 please, please, please, let me know!
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Robin Wolf
Kingfisher, OK 73750
robinwolf@pldi.net
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