I would say, carve some grooves in the side walls for heater wire, *maybe*
use it edge-wise instead, that is, 4.5" walls - *great* insulation that way,
but will use up a lot quickly.. (would be good if you have a long heat to
do... heh maybe anneal some white cast iron? Mmm, malleable iron!).
Otherwise, electricity is cheap.

If you know the thermal conductivity of the stuff, you can estimate power
consumption required for a certain temperature. Would suck to load it full
of wire and realize you can only get to 1400°F from 240V! (Psst... find a
240:480V transformer of good power rating

Only other thing I would suggest is to put more wire in the corners, and put
it on the largest walls if possible. Any wall that isn't contributing heat
is sucking it down, and corners, being surrounded by cooling wall on three
sides, will suck it down a lot.

Tim

--
"That's for the courts to decide." - Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

"Roy" wrote in message
...
Anyone have any plans or ideas on making a home made heat treat oven
of say 10 x 12 x 15 inches or so in size? Electrical operated and
running off 220 preferably, definately no propane powered furnace is
wanted.

I looked in the drop box fro such a project but have not seen any,.
but then again I may have missed one that is in there. Anyhow anyone
with any info on making a heat treat oven thats out there, I certainly
would appreciate some insight.

I have 2.5 x 4.5 x 9 inch insulated fire brick that I plan to use for
th liner / insulation and fit these inside a bent sheet steel box
hopefully. Not looking to make a huyge oven just something to heat
treat a few small items from time to time.

Any info appreciated.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.