Don Foreman wrote:
but I figure that 4400 watts (185 amps x 24 volts) will heat up a .5"
x 1" x 10" copper bar to near melting in about 64 seconds if there is
no heat loss. The blanket won't eliminate heat loss, but it may
reduce it enough to make it almost like welding unblanketed steel. I
used 10", figuring 5" of shielded region on either side of an exposed
1/2" to 1" wide weld zone about the same as 1" of bare steel since
copper is 5X as conductive and assuming metal beyond that distance to
not be much of a factor.
Most of your comment I generally agree with. But, I think you will need
to blanket much more of the part, out to several FEET on each side.
The thermal conductivity of copper is amazing, and a heat sink several
feet away can prevent you from heating a part to the temperature you
need. I have some experience with soldering and brazing large copper
parts, and it is always amazing how much heat comes out the far end of
the part!

Jon