Terrance Gallentine on sat 7 aug 04
I have been looking for a good way to mount kanthal elements to the ceiling
of my kilns for tile and glass work. I was told that the coiled elements
could be run through quartz tubing suspended from the ceiling of the kiln.
I want the kiln to be able to be able to fire midfire glazes, so the temps
that we are talking about would be around 2100F. Has anyone out there had
any experience with this type of thing and if so does anyone have any
suggestions for a supplier of the quartz tube?
Thanks,
Terry
Fredrick Paget on sun 8 aug 04
>I have been looking for a good way to mount kanthal elements to the ceiling
>of my kilns for tile and glass work. I was told that the coiled elements
>could be run through quartz tubing suspended from the ceiling of the kiln.
>I want the kiln to be able to be able to fire midfire glazes, so the temps
>that we are talking about would be around 2100F. Has anyone out there had
>any experience with this type of thing and if so does anyone have any
>suggestions for a supplier of the quartz tube?
>Terry__
Many years ago we had a quartz tube manufacturing unit at GTE
Sylvania Lighting Products (now Siemens Sylvania). It was on the
third floor of the building and the extruded tube came down out of
the bottom of the furnace, cooling, until it got to the ground floor,
where it was cut off into convenient lengths. That building was torn
down in the eighties and I think the new place is further north in
New Hampshire.
There was always scrap tubing that had inclusions or bubbles that
were not good for making lamps but would serve your purpose. The
tubing is used in the manufacture of high intensity discharge lights
of the mercury and metal halide type. General Electric and others
also make them. Maybe they would supply you.
We also make pure alumina tubing in short lengths for sodium vapor lamps.
I have seen a few kilns that used tubing and if I remember correctly
the tubing was inside the coils.
A higher grade quartz tubing should be available from laboratory
supply sources for a stiff price.
Fred
--
From Fred Paget, Marin County, California, USA
fredrick@well.com
Roger Graham on sun 8 aug 04
For Terrance, asking about use of quartz tube to suspend kanthal elements in
the ceiling of a kiln. Yes indeed, the method works very well. But don't
even consider trying to mount the coiled elements INSIDE a large-diameter
tube, it's easier to mount them by slipping the coiled element over the
OUTSIDE of narrower tubing.
Obtaining the necessary fused silica tube is no problem if your local waste
disposal "trash dump" has a recycling facility, where you can pick up
discarded electric room heaters. Here (Australia) these items are called
"radiators", and contain one or sometimes two lengths of silica tube,
diameter usually 9mm or 10mm. The tubing encloses the nichrome heating
element, for support and safety in normal use. When or if the nichrome coil
fails, the whole device is usually discarded but the silica tube is still as
good as new. Over a time I've salvaged about 20 of these from our local
recycling depot for a dollar or two each, to be cannibalized for element
supports.
Email me off list if you wish, and I can send photographs and other info for
a glass-forming kiln with elements suspended in the roof, using this method.
Briefly, each length of silica tube is supported at the ends in a
bisque-fired mounting bracket especially made for the purpose, using a mix
of 50:50 stoneware clay and fireclay. The mounting brackets can double up as
fibre blanket anchors, if that's the way you plan it.
Roger Graham, near Gerringong, Australia
http://members.optusnet.com.au/~rogergraham
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