Dennis Gerasimov on mon 30 nov 09
Hi,
I have an old kiln (Sno Industries P-22), which is specified to cone 6
in the manual. The brick is of the 2300 degrees kind, I believe. It
reaches cone 6 fairly fast (approx. 200 degrees F per hour rise during
the last 90 minutes), and I feel it can go higher. I understand that
going to cone 10 is probably out of the question, but could I go to cone
8? I realize it will shorten the life of the brick, and I am prepared to
sacrifice it if I can get a couple hundred cone 8 firings out of it.
If I extrapolate the curve from cone 6, it should be around 2260 degrees
when it reaches cone 8. Will the brick hold?
Also, anyone knows what the brick failure looks like? Is it going to
start melting or crumbling after such harsh firings?
Sort of in the same vein, can anyone recommend a US supplier of
stainless steel sheets to make an outer shell for a new kiln?
Thank you!
Dennis
Arnold Howard on mon 30 nov 09
From: "Dennis Gerasimov"
> If I extrapolate the curve from cone 6, it should be
> around 2260 degrees
> when it reaches cone 8. Will the brick hold?
> Also, anyone knows what the brick failure looks like? Is
> it going to
> start melting or crumbling after such harsh firings?
--------------
Usually a kiln is rated to the temperature that it can
reasonably reach with the available amperage. Even if your
kiln can reach cone 8, however, there may be a safety reason
that the kiln was rated only to cone 6. That's why I don't
advise going higher than the kiln's rated temperature.
The bricks will develop vertical cracks when they have been
overfired--maybe two cracks per brick. I've seen that here,
because we sometimes intentionally overfire a kiln for
safety testing. That type of brick damage shouldn't happen
at cone 8, though.
If you ever consider buying a kiln that has vertical cracks
in the firebricks, you know that it has been overfired.
We sell stainless steel kiln jackets.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
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