vince pitelka on fri 5 apr 02
> Maggie is structurally sound, but there are cracks in the brick walls, a
> number of them mostly in the rear wall and sides. The bricks of the arch
and
> door are crack free. Cracks seem to vary between hairline thickness (no
> prob) and 1/8" at the thickest. You cannot see more than 1/2 a brick's
> thickness 'into' these fissures, so it appears at most that there would be
> some efficiency loss due to these defects, rather than a safety or
> structural hazard.
Mark -
It is worth it to take the time to fill the cracks. Don't mess with "gunned
on" coatings unless you want to give the kiln a coat of ITC. It is sprayed
on in a very thin layer. Just get a small supply of high-duty refractory
patching compound, like APGreen Greenpatch 421. It is still being sold by
Harbison-Walker, and most good refractory suppliers have it in stock. Wet
the adjacent surfaces very thoroughly with a sponge or spritz bottle, and
then work the Greenpatch into the cracks with a sturdy spatula. It adheres
extremely well, and will last as long as the brick.
If the burners and safety systems on the kiln are working fine, then don't
mess with them. When it does become necessary to upgrade them, get rid of
those ridiculous porcelain burner tips inside the firebox. Back off the
burner mounts, replace the burner tubes, and mount normal threaded
flame-retention nozzles on the tubes, with the tips about 1/2" outside the
burner port. That is a much superior system.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Jim V Brooks on fri 5 apr 02
I repaired an Alpine by removing the old brick and inserting new.. i got a
gallon container of high fire brick cement from Acme Brick Company...it was
an easy job.. However, if the cracks are not too large, most of them may
close when the kiln is fired up and the bricks expand from the heat. Jim in
Denton...
Mark Potter on fri 5 apr 02
To all you kiln experts out there - if you have experience with Alpines,
please lend me your hard won advice -
I acquired recently (thanks to Clayart and Christina Burns at Ottawa
University) an old Alpine 24 cubic foot updraft kiln, (her name is Maggie)
in need of TLC. Maggie and I bounced east over Interstate 70 earlier this
week. We're in love.
Maggie is structurally sound, but there are cracks in the brick walls, a
number of them mostly in the rear wall and sides. The bricks of the arch and
door are crack free. Cracks seem to vary between hairline thickness (no
prob) and 1/8" at the thickest. You cannot see more than 1/2 a brick's
thickness 'into' these fissures, so it appears at most that there would be
some efficiency loss due to these defects, rather than a safety or
structural hazard.
I remember seeing in CM, something about restoring an old Alpine, or
Minnesota flat-top, perhaps applying that gunned on refractory coating.
Perhaps it was Mel's kiln that got the treatment - anyway I can't find the
article. Seems it was a coating "ITC" is that right?, that would adhere to
anything, and was robust in tolerating expansion/contraction, even salting.
My questions are thus:
1) Cracks in kilns are inevitable, this I understand - but I'd like not to
waste my fuel dollar unnecessarily. Is it worth trying to fill these, or
cover them over with that gunned on stuff?
2) The cracks seem to have resulted from a expansion contraction cycle
design/incompatibility between the laid brick core of the kiln, and the
steel frame surrounding it. Do such cracks close up during firing?
3) The kiln is fitted with the standard equipment from the 1970's, two
thermocouples, fire-eyes, etc. Most of it appears in good working order, but
from a safety perspective should any of this stuff be decommissioned and
replaced with anything newer? The forced air burners are in good condition
except the burner nozzles need replacement. Any suggestions about where to
go for replacement parts/upgrading? Alpine/Clayart themselves?
I got Maggie on the heels of building a downdraft (larger), but I love the
firings these Alpines can give, a quick cycling up and down for certain
glazes is wonderful. I'm happy to work on her a while before firing her up -
if you have suggestions of how to go I'm all ears.
Regards,
Mark Potter
New Haven, CT
Paul Herman on fri 5 apr 02
Mark,
I used ITC on an old cracked soft brick kiln and it buckled up next to
the cracks and fell off, taking some brick with it, so beware. I'm
really glad I didn't put any on the arch like I was advised to do.
Best wishes,
Hardway Herman
----------
>From: Mark Potter
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Alpine Refurbishment
>Date: Fri, Apr 5, 2002, 12:18 PM
>
> My questions are thus:
>
> 1) Cracks in kilns are inevitable, this I understand - but I'd like not to
> waste my fuel dollar unnecessarily. Is it worth trying to fill these, or
> cover them over with that gunned on stuff?
Michael C Hill on sat 6 apr 02
The best trick I know to fix cracks in kilns is to take strips of
ceramic fiber, soak them in kiln wash and shove it into the cracks using
a screw driver or putty knife untill the flush with the kiln wall. After
it dries, clean any mess off the walls so it wont spall off onto the
pots. If the crack is at the top of the kiln over pots, I would probally
leave it alone.
Michael
ASHPOTS@AOL.COM on sat 6 apr 02
I also have a old Alpine 24,,,,,i got high pressure burners from Marc Ward
and the kiln fires nice... Slow cooling,,, which is fine for my ash glazes..
I sprayed with ITC years ago...
Mark
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