Fredrick Paget on thu 11 apr 02
Tig-
Those globar kilns were made by the old defunct Alpine Kiln Co. I have seen
a picture of one in Sanders book "Glazes for Special Effects" and I hear
that there is one at the University of SanFrancisco that is not in working
condition.
Those Globar rods are silicon carbide rods and the kilns would go to about
cone 17 and can stand reduction firing with introduced fuels.
Since the resistance of the rods is very low it was necesary to feed in a
very high current at a low voltage to get the power needed. Also the
voltage had to be adjustable. The rods resistance changes a good deal as
they heat up and also as they age. This was done with a very large and
expensive tap changing transformer with its asociated tap changing switch.
Kilns using Globar rods with a spiral cut tube type of rod have a higher
resistance and can be run off line voltage but the resistance changes still
occur so they need a sophisticated electronic controller.
Contemporary Kilns in Novato, California will make you one custom built to
order. I hope you can afford it.
Fred
>Back when I had more of my hair and less of my waist, at the University of
>Florida, we used a Globar kiln for firing bisque. I remember it was
>front-loading, and of substantial size. The heating elements were rods
>about 1/2" in diameter, as I recall.
>
>Does anyone know if this type of kiln is still manufactured? Still as a
>"Globar?"
,,,,
>Thanks for any help,
>
>Tig
From Fred Paget, Marin County, California, USA
Dupre Mr Marcy M on thu 11 apr 02
Many, many years ago, at a campus far away...
Back when I had more of my hair and less of my waist, at the University of
Florida, we used a Globar kiln for firing bisque. I remember it was
front-loading, and of substantial size. The heating elements were rods
about 1/2" in diameter, as I recall.
Does anyone know if this type of kiln is still manufactured? Still as a
"Globar?"
I'd like to find one for my home studio.
Thanks for any help,
Tig
Play Dirty!
Hank Murrow on thu 11 apr 02
>Tig wrote;
>Many, many years ago, at a campus far away...
>
>Back when I had more of my hair and less of my waist, at the University of
>Florida, we used a Globar kiln for firing bisque. I remember it was
>front-loading, and of substantial size. The heating elements were rods
>about 1/2" in diameter, as I recall.
>
>Does anyone know if this type of kiln is still manufactured? Still as a
>"Globar?"
>
>I'd like to find one for my home studio.
Dear Tig;
"Globar" is a tradename for the elements themselves, which
come in many configurations, and are made of Silican-carbide, which
conducts electricity well enough.
Several Manufacturers still make such kilns, and they are
pricey, if more or less bulletproof. Suggest you do a search on
Google for Globar, and Globar kilns.
Best, Hank
vince pitelka on thu 11 apr 02
> Does anyone know if this type of kiln is still manufactured? Still as a
> "Globar?"
> I'd like to find one for my home studio.
Tig -
I wish that Globar kilns WERE affordable. Globar was the brand name of the
silicon-carbide element rods, and they also made kilns featuring their
element rods. The rods are fairly permanent, and unaffected by reduction,
but they are VERY expensive, and they require a very large power supply to
operate. They draw a lot of amperage.
Best wishes -
- 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/
Tom Buck on fri 12 apr 02
Bruce,
Why do globars put out big heat? because solid Silcon Carbide has
a low resistance to electron flow ("ohms"). As a guess, I'd expect a 10 mm
diametre bar, 750 mm long, to have a resistance under 10 ohms (5 ???). if
say one bar was connected to 235 volt power, and the ohms was 10, you'd
pull 23.5 amperes, and the power output in Joules/second (Watts) would be
over 5.5 kilowatts! even industrial power at 205 volts would put 4.2 kW
(15 megajoules per hour) into the kiln. so 2 such globars would equal the
standard 7.0 cubic foot electric kiln with 5/6 elements. (10.5-11.0 kW).
why aren't there more globar kilns? because, I suspect, the
installation is tricky, not easily done by me or you. and the special
gadgetry to ramp the output makes the kiln quite expensive.
good pots. Peace. Tom B.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
Bruce Girrell on fri 12 apr 02
vince pitelka wrote:
> [Globar kilns] require a very large power supply to
> operate. They draw a lot of amperage.
I don't understand this statement. Why would a Globar kiln draw any more
power than any other electric kiln that fires to the same temperature? Is
silicon carbide somehow less efficient at converting electrical energy to
heat than nichrome wire? It seems to me that the primary efficiency of an
electric kiln would be determined by its insulation, not its elements.
Bruce "enquiring minds want to know" Girrell
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