Anne Wellings on sat 23 sep 06
I need some answers for a friend who is replacing all the elements in her
electric kiln and wants to deal with some damaged bricks at the same
time. The first problem is that she is trying to re-cement chunks of soft
brick that have broken away, and is using Sairset to do so, but is having
trouble getting it to work. It does not seem to allow the pieces to stick
together, and she has tried thinning it with water, and will try wetting
the brick first. Any ideas on this or better products to use?
The other problem is that where an element burned out, there is a dark
discolored area in the brick that has become very hard. She wonders
whether this area, when it comes in contact with the new element, is
likely to cause it to burn out. I found a post in the archives that
mentioned a similar-sounding discolored area and said it should be
chipped out with a screwdriver and that it could burn out the new
element. But my friend said there is another similar, though maybe
smaller, spot in the kiln that has not burned out an element thus far. If
this spot sounds like a big problem for the future of the new element,
then she's thinking she may have to replace the brick.
Any thoughts on this situation are appreciated.
Anne
Steve Mills on mon 25 sep 06
Dear Anne,
Wetting the brick prior to applying cement will help, though there are
brick cements that do not require the pre-wetting.
Sairset is not one of those, so the brick sucks out the moisture and
defeats the process.
Places where elements have burned out and left a dark patch need to be
scraped back to plain brick, as the dark patch contains element residue
and could cause another burn-out.
Better safe than sorry!
Best.
Steve
Bath
UK
In message , Anne Wellings writes
>I need some answers for a friend who is replacing all the elements in her
>electric kiln and wants to deal with some damaged bricks at the same
>time. The first problem is that she is trying to re-cement chunks of soft
>brick that have broken away, and is using Sairset to do so, but is having
>trouble getting it to work. It does not seem to allow the pieces to stick
>together, and she has tried thinning it with water, and will try wetting
>the brick first. Any ideas on this or better products to use?
>
>The other problem is that where an element burned out, there is a dark
>discolored area in the brick that has become very hard. She wonders
>whether this area, when it comes in contact with the new element, is
>likely to cause it to burn out. I found a post in the archives that
>mentioned a similar-sounding discolored area and said it should be
>chipped out with a screwdriver and that it could burn out the new
>element. But my friend said there is another similar, though maybe
>smaller, spot in the kiln that has not burned out an element thus far. If
>this spot sounds like a big problem for the future of the new element,
>then she's thinking she may have to replace the brick.
>
>Any thoughts on this situation are appreciated.
>
>Anne
--
Steve Mills
Bath
UK
Arnold Howard on mon 25 sep 06
From: "Anne Wellings"
To:
>I need some answers for a friend who is replacing all the
>elements in her
> electric kiln and wants to deal with some damaged bricks
> at the same
> time. The first problem is that she is trying to re-cement
> chunks of soft
> brick that have broken away, and is using Sairset to do
> so, but is having
> trouble getting it to work. >
> The other problem is that where an element burned out,
> there is a dark
> discolored area in the brick that has become very hard.
Anne, broken bricks can usually be left unrepaired without
affecting the firing results.
A few weeks ago someone showed me photos of a very old
Paragon kiln someone had given him. He was concerned about
the brick damage and had compiled a list of replacement
bricks that he wanted to order. He wondered if the kiln was
even worth repairing.
I looked at the pictures and told him that the kiln was in
pristine condition. I saw only a few broken element grooves,
which is minor.
Here are several brick repair ideas to try:
1) You can hold a broken brick groove in place with two
element staples, which are U-shaped pieces of element wire.
Angle the staples slightly downward and inward toward each
other so that gravity helps hold the groove in place.
2) If you have lost the element groove, you can hold the
element in place with a couple of element staples.
3) An element groove is difficult to repair with cement,
because the brick surface to be cemented is so narrow. It is
easier, however, if you sand the broken surfaces so that
they are flat instead of jagged. You will need to make a new
element groove that will mate with the main brick. The gap
in the brick seam should be no wider than 1/16". Otherwise
the brick will probably break later.
If you want to see the ideal brick seam, examine a brick lid
or bottom. They are made by craftsmen who work with bricks
all day long. The seams are usually only 1/32" - 1/16" wide.
Thicker seams tend to break due to the difference of
expansion between the brick and cement.
As Steve Bath suggested, you should always dig out the
discolored spots in an element groove. Use a screwdriver and
dental mirror. If you can't get a screwdriver into the
groove, use a curved dental tool. Before installing the new
elements, vacuum the grooves.
The number one reason a new element burns out is loose
element connectors. So be sure to read the instructions that
come with replacement elements. That should include
information on tightening the connectors.
Elements are easy to replace. Many years ago I tested the
new Paragon SnF-82, a kiln that had our first "tuned
elements." I fired the kiln, studied witness cones, and
after each firing replaced all the elements. (We changed the
ohms of the elements each time.) With a little practice, I
could replace the elements in about 45 minutes, and without
damaging the bricks. If I can do it, you and your friend
certainly can too.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
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