Snail Scott on mon 11 feb 02
A while back, I posted my plans for shortening
my kiln. Well, as we know, no battle plan survives
contact with the enemy, but here's an update:
I burned out my bottom element last week, so since
I'd be dismantling the whole thing to reach that
ring, I decided to go for it. My plan: to get a
30" aluminum stopsign from the scrapyard downtown,
and use the 1" fiberboard that I just scored for
free(!) to make two layers to cover it. I figured
the sign would be rustproof, lightweight and rigid
(and already the right shape, more or less). I would
rest it on about 6 bricks laid flat in a radial
(star) pattern to support the sign and still allow
airflow underneath.
I unstacked the kiln, and discovered
that when the spot-welds on the floor jacket gave
out a little while ago, it allowed the floor to
lose just about all structural integrity. I'd planned
to get new hose-clamps (one broke, the other one
lost its welds), but thought it could wait for
one more firing. WRONG! The kiln stand sits well
inside the 'footprint' of the kiln, and when my
kitten jumped up on one side, the whole floor
collapsed into a dozen pieces and a zillion crumbs.
I didn't make it to the salvage yard in time to
get a stopsign, and I figured the fiberboard really
wasn't rigid enough without it, at least since the
floor collapsed. So, I pulled the lid off my old
'beater' kiln, (a Skutt 231).
Since my kilnyard concrete floor isn't quite flat,
I decided that the radial arangement of bricks
would be hard to level. So, I dug out an old kiln
stand that had the legs bolted on instead of welded.
I unbolted the legs and put a flat brick under each
corner. (I'd like to put the stand directly on the
ground, but I'm not sure how hot it would get under
there with no airflow at all, even with a 2" airgap.)
I put the old lid on top of that, then put the floor
fragments on top of it like a jigsaw puzzle. I put
the old steel jacket strap around it and cinched it
tight with several wraps of baling wire. (Probably
useless if the floor needed its structural integrity,
but the lid underneath should serve for that.) After
I replaced the bad element and restacked the kiln,
I ended up with a double-insulated floor, and it's
still several inches shorter than it was - a huge
improvement when loading the bottom level! Eventually,
I'll get that stopsign and fiberboard, and when I
scrap the stand altogether I should gain (or rather,
lose) another couple of inches in height. In the
meantime, I'll have the current load fired by my
tuesday deadline!
Looking back, I wonder if the floor problem was
exacerbated by the kiln stand originally. I'd had
floor cracks for a while, which I chalked up to
damage in transit, riding thousands of miles in the
back of a U-Haul. The floor seemed to be getting
less and less level lately, but I just shimmed up
the posts with a little kiln putty and kept firing.
Then the steel band popped off...
(You think popping noises are disturbing during a
firing, try clanging sounds!)
I see several contributing factors which might have
been mitigated by a different kiln stand than the one
the manufacturer provided.
1. The walls are outside the area supported by the
stand, so any pressure on them would rest on the
unsupported perimeter of the kiln. As a short person,
I always had to stand on a crate to reach the bottom,
and often figured it was safer to just lean on the
edge. I can't count the number of times my feet have
left the ground while loading, putting my whole
weight on the kiln wall. It never seemed to hurt the
wall, but I never stopped to think about the floor.
2. The posts holding up the shelves also rest outside
the supported area of the floor. Not as far out as
the walls, true, but with 100# of clay resting on
them, I wonder if that's enough. In the future, I will
check the location of the stand corners and try to
put the posts above them.
I begin to wonder if those stresses led to the
failure of the hose clamps first, rather than an
initial failure of the clamps allowing the other
factors to do their damage. If I ever get a new
kiln, the first thing I'll do is shorten the stand,
not just for my own convenience, but maybe to save
the kiln.
-Snail
(owner of the world's ugliest kiln, now, but at
least it's shorter!)
MOLINA, RAFAEL on mon 11 feb 02
-----Original Message-----
From: Snail Scott [mailto:snail@MINDSPRING.COM]
Sent: Monday, February 11, 2002 4:33 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: adventures in kiln shortening
A while back, I posted my plans for shortening
my kiln. Well, as we know, no battle plan survives
contact with the enemy, but here's an update:
I burned out my bottom element last week, so since
I'd be dismantling the whole thing to reach that
ring, I decided to go for it. My plan: to get a
30" aluminum stopsign from the scrapyard downtown,
and use the 1" fiberboard that I just scored for
free(!) to make two layers to cover it. I figured
the sign would be rustproof, lightweight and rigid
(and already the right shape, more or less). I would
rest it on about 6 bricks laid flat in a radial
(star) pattern to support the sign and still allow
airflow underneath.
I unstacked the kiln, and discovered
that when the spot-welds on the floor jacket gave
out a little while ago, it allowed the floor to
lose just about all structural integrity. I'd planned
to get new hose-clamps (one broke, the other one
lost its welds), but thought it could wait for
one more firing. WRONG! The kiln stand sits well
inside the 'footprint' of the kiln, and when my
kitten jumped up on one side, the whole floor
collapsed into a dozen pieces and a zillion crumbs.
I didn't make it to the salvage yard in time to
get a stopsign, and I figured the fiberboard really
wasn't rigid enough without it, at least since the
floor collapsed. So, I pulled the lid off my old
'beater' kiln, (a Skutt 231).
Since my kilnyard concrete floor isn't quite flat,
I decided that the radial arangement of bricks
would be hard to level. So, I dug out an old kiln
stand that had the legs bolted on instead of welded.
I unbolted the legs and put a flat brick under each
corner. (I'd like to put the stand directly on the
ground, but I'm not sure how hot it would get under
there with no airflow at all, even with a 2" airgap.)
I put the old lid on top of that, then put the floor
fragments on top of it like a jigsaw puzzle. I put
the old steel jacket strap around it and cinched it
tight with several wraps of baling wire. (Probably
useless if the floor needed its structural integrity,
but the lid underneath should serve for that.) After
I replaced the bad element and restacked the kiln,
I ended up with a double-insulated floor, and it's
still several inches shorter than it was - a huge
improvement when loading the bottom level! Eventually,
I'll get that stopsign and fiberboard, and when I
scrap the stand altogether I should gain (or rather,
lose) another couple of inches in height. In the
meantime, I'll have the current load fired by my
tuesday deadline!
Looking back, I wonder if the floor problem was
exacerbated by the kiln stand originally. I'd had
floor cracks for a while, which I chalked up to
damage in transit, riding thousands of miles in the
back of a U-Haul. The floor seemed to be getting
less and less level lately, but I just shimmed up
the posts with a little kiln putty and kept firing.
Then the steel band popped off...
(You think popping noises are disturbing during a
firing, try clanging sounds!)
I see several contributing factors which might have
been mitigated by a different kiln stand than the one
the manufacturer provided.
1. The walls are outside the area supported by the
stand, so any pressure on them would rest on the
unsupported perimeter of the kiln. As a short person,
I always had to stand on a crate to reach the bottom,
and often figured it was safer to just lean on the
edge. I can't count the number of times my feet have
left the ground while loading, putting my whole
weight on the kiln wall. It never seemed to hurt the
wall, but I never stopped to think about the floor.
2. The posts holding up the shelves also rest outside
the supported area of the floor. Not as far out as
the walls, true, but with 100# of clay resting on
them, I wonder if that's enough. In the future, I will
check the location of the stand corners and try to
put the posts above them.
I begin to wonder if those stresses led to the
failure of the hose clamps first, rather than an
initial failure of the clamps allowing the other
factors to do their damage. If I ever get a new
kiln, the first thing I'll do is shorten the stand,
not just for my own convenience, but maybe to save
the kiln.
-Snail
(owner of the world's ugliest kiln, now, but at
least it's shorter!)
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