James R. Goodhue on fri 12 apr 96
Just a comment about using graphite as reduction. One time I was asked to look
at some electric kilns at a major oil company's large research facility here in
S. Calif. They did some weird stuff in their electric kilns, had them all
hooked up to computers with monitoring programs etc. and had old style cam
controllers. This was about 12 years or so ago. They made test batches of
graphite from coke, some type of coal ore or something, and experimented with
various materials. The electric kiln I looked at had black soot inside and
whatever they had fired in it had attacked the heating elements and melted them
into the firebrick. All elements throughout the kiln were melted into the
brick like this. Just parts of each element were affected. Big areas of K-23
softbrick were eaten away and black with carbon in the eaten away areas. The
parts of elements left had to be removed, the damaged areas of black carbonized
soft brick had to be dug out and scraped away with a screwdriver. Then bulk
ceramic fiber was stuffed into the damaged brick areas and new elements
installed so the kiln could stay in service. I had never seen anything like
it, that black carbon material eating up the elements and brick. I haven't
seen anything like it since. They said they weren't firing above about 2000 F.
They also had an interesting induction furnace that they fired the graphite
samples in to about 2600 degrees centigrade. If the graphite firing came out
good then they knew the vein of coke ore was good quality for making more
graphite. This tube kiln, I was told works like a microwave oven to heat. At
2600 C it was white white hot and when you opened the peephole this beam of
light would shoot across the room like a really strong spotlight on the wall.
It was fun for me with my artist/potter background to see this high tech
industrial stuff at the time.
Just a comment that messing with the graphite in electric kiln reduction
could cause some unwanted repairs. Use an old electric kiln you like to fix.
Fire the next firing in oxidation to clean things out after each experiment.
What others have said about being careful and leery of toxic fumes from plastic
materials, etc. seems like good advice. Good to be aware of potential hazards
when experimenting. One time when I was a little younger and more naive about
hazards of materials, not really thinking through the potential hazards, I had
mixed some shavings from surfboard foam with some clay, just a small pot made
from it. The fumes from that little piece exiting my kiln were so bad I lost a
day's work as I bailed out of the shop and had to leave it airing out all day.
I laugh now and recollect, how stupid was I in the interest of experimentation
and learning... that surfboard foam is toxic stuff by itself... and to mix it
in clay and fire it... not really too bright... did learn something though ...
it stinks ... a lot...Oh Well!
Jim
Jim Goodhue, San Clemente, Calif. Email: jgoodhu@cello.gina.calstate.edu
Jim Goodhue, San Clemente, Calif. Email: jgoodhu@cello.gina.calstate.edu
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