Paul on sun 30 nov 03
Hello,
the seal on one side of my car kiln as a few leaks in it, and i found out
that the one part of the kiln where i can not get copper reds is right near
the biggest leak, so there must be a correlation. I think the leak started
because i had to do some maintenance on the car it's self after the firest
firing, and things got moved around just enough to cause the leak.
The only simple idea i can think of is to try to plaster some Greenpatch on
the seal -- i need to build some areas up about 1/4" to fill gaps. But i
would think this will eventually spall off. Does anyone have any other ideas
on how to fill the cracks in the seal between the car and the kiln? thanks,
Paul B
Falmouth,Ky
Hank Murrow on sun 30 nov 03
Dear paul;
I would build up the Greenpatch maybe on both mating surfaces, slap a
piece of plastic wrap on each patch and close the kiln, letting the
mating surfaces close together. Let harden somewhat and open the car to
trim off excess that may be squeezed out.
Hank in Eugene
On Nov 30, 2003, at 9:45 AM, Paul wrote:
> Hello,
> the seal on one side of my car kiln as a few leaks in it, and i found
> out
> that the one part of the kiln where i can not get copper reds is right
> near
> the biggest leak, so there must be a correlation. I think the leak
> started
> because i had to do some maintenance on the car it's self after the
> firest
> firing, and things got moved around just enough to cause the leak.
> The only simple idea i can think of is to try to plaster some
> Greenpatch on
> the seal -- i need to build some areas up about 1/4" to fill gaps. But
> i
> would think this will eventually spall off. Does anyone have any other
> ideas
> on how to fill the cracks in the seal between the car and the kiln?
Vince Pitelka on sun 30 nov 03
> the seal on one side of my car kiln as a few leaks in it, and i found out
> that the one part of the kiln where i can not get copper reds is right
near
> the biggest leak, so there must be a correlation. I think the leak started
> because i had to do some maintenance on the car it's self after the firest
> firing, and things got moved around just enough to cause the leak.
> The only simple idea i can think of is to try to plaster some Greenpatch
on
> the seal -- i need to build some areas up about 1/4" to fill gaps. But i
> would think this will eventually spall off. Does anyone have any other
ideas
> on how to fill the cracks in the seal between the car and the kiln?
thanks,
Paul -
It is a shame that this happened, and it can only be because the car seal
was not done properly to begin with. Is it a stepped taper fit? That is
the only kind of car seal that really works for a downdraft kiln. I have
seen downdraft car kilns with a taper seal in professional use for decades
without needing any maintenance to the car seal.
If it is not a taper fit, I do not know what to suggest because you cannot
eliminate the gap without causing the car to drag during opening and
closing, which will only cause the gap to return.
You can get away with a little clearance on the car fit on an updraft kiln,
thus all the shuttle kilns with doors at both ends and two cars, or the
envelope kilns with two ware platforms. But on a downdraft kiln you cannot
have any clearance at all on the car fit, and a stepped taper fit is the
only design that works in this regard and still allows you to move the car
in and out with no friction.
You may already know this, but for clarity, this kind of car fit has a
three-layer brick floor, totaling 7.5" thick. The steel car deck is about
1/4" lower than the top of the U-shaped concrete block base that the kiln
rests on. The bricks on the inner edge of the "socket" that the car will
fit into are laid up against a board "strait-edge" that defines a 1" taper
from front to back - 1/2" on each side. On the firebox floor, at either
edge inside the kiln, the bricks are laid up against the board so that each
course overhands the one beneath by 1/2". So you have a taper fit, plus a
stepped fit, both working together.
To further clarify, you lay the inside course of the first layer of bricks
against a board "strait-edge front to back with the requisite taper, then
for the next layer of floor bricks you move the board 1/2" toward the center
of the kiln, and lay the second layer, then move it another 1/2" towards the
center of the kiln for the third layer.
When the kiln body is completed, drape strips of wax paper over the edge of
the firebox floor front to back the length of the firebox so that they hang
down into the car socket. Roll the car frame into place, lay the bricks
directly up against the wax paper with no clearance at all, fill in with cut
softbricks shims wherever necessary to get a tight floor. Each layer of car
floor bricks will be stepped back 1/2" from the previous layer on each side.
Because the car deck is 1/4" lower than the concrete block base under the
firebox floor, there will be no contact between the horizontal surfaces of
the overhangs. The only contact will be where the taper of the car seats
against the taper of the kiln. And the instant you start to pull the car,
the surfaces move apart, and there will be no contact at all and no
friction. The wax paper guarantees that.
It is really so simple to build a car kiln with a proper seal on the car. I
do not know what kind of car seal you used, so I do not know why you are
having this trouble now, but it is a shame, on such a new kiln.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
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