Lesley Alexander on mon 9 aug 99
I have an updraft gas kiln with an old kiln shelf used as a vent. It
slides back and forth along iron bars welded to the frame. Those bars have
been bubbling and flaking. This could result in specks on the pots as they
fire, and also the shelf doesn't slide smoothly so I have to bang it, more
specks. Anybody else have this problem? I could buy more iron bars, is
there anything better? What about porcelain balls to roll on, held in a
porcelain track (but that would have to set on iron bars anyway, I
suppose). Is there any material that won't bubble and flake, that could be
welded to the frame?
I did try aluminum bars, alumina is refractory, right? Mistake!
Fortunately I only lost a couple of not important bisque pieces, decorated
with slag of aluminum and whatever it was mixed with.... One for the dumb
try department.
What does everybody else do? Lesley in Santa Barbara
Dale A. Neese on tue 10 aug 99
I have made myself stand on a ladder and sweep the rails with a broom just
before loading the kiln and then use a shop vac to clean as much iron
particles away. I usually vac out the burners and the kiln floor at the same
time. A little preventive maintenance. Until the hood over my updraft was
removed and the metal roof raised, I was getting iron contamination down the
flue. I once covered the pots stacked under the flue with an old blank kiln
washed shelf. Now to protect the new metal shed roof from the flames, I have
fiber attached to expanded metal hanging three feet above the flue and three
feet under the roof.
Dale Tex
Fredrick Paget on tue 10 aug 99
Lesley,
There are metal alloys that can take it in the chimney of a kiln. I have a
damper in my small gas lustre kiln made of Hastelloy X.It looks fine and no
corrosion after about 10 firings (once to cone 10 but usually lower).
I had a piece of it in my junk pile for years - somebody gave me it when
he was making a boat and was using part of a sheet of it on the bottom of
the boat in salt water as a grounding electrode of sorts.
It is the kind of metal that they make afterburners for jet fighters out
of. The name and alloy were stencilled on it but I didn't know what it was
until I looked it up on the internet.:
http://www.hpalloy.com/DataSheets/hastx.htm
. It is a nickel chromium molybdenum iron cobalt alloy. It will take 2150
deg.F. for thousands of hours. If you could get a couple of angle irons
made of it it would solve your problem.It is weldable using MIG or TIG
welders.
I have no idea what it would cost but it probably is expensive.
Regards, Fred Paget
>
>Date: Mon, 9 Aug 1999 10:29:32 EDT
>From: Lesley Alexander
>Subject: Updraft kiln, sliding shelf vent
>
>----------------------------Original message----------------------------
> I have an updraft gas kiln with an old kiln shelf used as a vent. It
>slides back and forth along iron bars welded to the frame. Those bars have
>been bubbling and flaking. This could result in specks on the pots as they
>fire, and also the shelf doesn't slide smoothly so I have to bang it, more
>specks. Anybody else have this problem? I could buy more iron bars, is
>there anything better? What about porcelain balls to roll on, held in a
>porcelain track (but that would have to set on iron bars anyway, I
>suppose). Is there any material that won't bubble and flake, that could be
>welded to the frame?
> I did try aluminum bars, alumina is refractory, right? Mistake!
>Fortunately I only lost a couple of not important bisque pieces, decorated
>with slag of aluminum and whatever it was mixed with.... One for the dumb
>try department.
> What does everybody else do?
>Lesley Alexander
>in Santa Barbara
>From Fred Paget, Marin County, California, USA
Mike Gordon on tue 10 aug 99
Hi Lesley,
I had the same problem with the kiln the high school I teach at
purchased from a kiln co. in Novato, Ca. The soultion is tear the old
metal out or have someone do it for you. Cement some hard brick as
guides for the damper and hard brick for the shelf to slide on. Mine
works effortlessly, in fact I've almost ripped it off by using the old
method of jerking and banging. Just keep the surface clean up top. Mike
Jeff Ferguson on wed 11 aug 99
I replaced my track with a shelf on a hinge. The shelf is lifted by a small
boat trailer winch. It is easy to controll how much it is open by each click
of the winch and I am away from the heat and no trash in the kiln. I
struggled with that prblem and this works great.
Amy Ramsey on thu 12 aug 99
Lesley,
At the pottery where I work, we load an empty shelf at the top, just a few
inches (6 mebbe?) under the vent. Ours is an Olsen 24cu updraft, and the
"flue" operates as yours does, and sometimes the kiln shelf gets pulled back
and wedges itself, so it has to get "bumped" back into line. The bare top
shelf catches all the brickabrack that manages to make it down into the
kiln. Hope this helps. Best to you.
Amy Ramsey
in Bend, where we, too, have to unplug EVERYTHING and hide from the thunder
and lightening.....only 3 or 4 houses have burned to the ground so far from
the lightening.....
-----Original Message-----
From: Lesley Alexander [mailto:celadon@silcom.com]
Sent: Monday, August 09, 1999 7:30 AM
Subject: Updraft kiln, sliding shelf vent
----------------------------Original message----------------------------
I have an updraft gas kiln with an old kiln shelf used as a vent. It
slides back and forth along iron bars welded to the frame. Those bars have
been bubbling and flaking. This could result in specks on the pots as they
fire, and also the shelf doesn't slide smoothly so I have to bang it, more
specks. Anybody else have this problem? I could buy more iron bars, is
there anything better? What about porcelain balls to roll on, held in a
porcelain track (but that would have to set on iron bars anyway, I
suppose). Is there any material that won't bubble and flake, that could be
welded to the frame?
I did try aluminum bars, alumina is refractory, right? Mistake!
Fortunately I only lost a couple of not important bisque pieces, decorated
with slag of aluminum and whatever it was mixed with.... One for the dumb
try department.
What does everybody else do? Lesley in Santa Barbara
| |
|
