On Tue, 15 Jul 2008 10:14:52 -0700, rashid111 wrote:

Assuming one has a fairly straight approx 4.5" OD x 10" long round motor
with smooth surface, what would be a good way to get some heat sink type
of deal ?

I am thinking about

A) getting say 3/8 or 1/2 alum channel, cutting it into pieces the
length of the motor and attaching the "strips" flat bottom toward the
motor around the circumference. 3-4 zip-ties holding the Us against the
motor

Rather than a lot of separate channels, perhaps get some heatsinks
like ebay # 220255259730. (I have some heatsinks about twice that
big, from junked motor controllers.) Bend it to be a reasonably close
fit to the diameter, or cut a shallow 2.25"-radius channel in some
3"x1" aluminum bar and mount the heatsink on the flat side. If you
made two assemblies you could bolt them together with 7" bolts across the
motor. Make the motor casing as smooth as you can and use a minimal
amount of heatsink grease between the motor and heatsink assembly.

If you go with your first plan, use large stainless steel ring
clamps (like for round ducts) rather than zip-ties to hold your
channels against the motor.

Ebay # 170237692452 will cut wide heatsink channel to size, but is
somewhat more expensive than big surplus heatsinks.

B) doing something with copper or alum sticky foil, where you create as
many folds as possible in a "pleaded" fashion - infinitely messier
affair, but would it be more efficient in dissipating the heat ?

Folded fins of foil won't do much because the tiny cross-sections
won't conduct enough heat away from the motor.

If you have a good chilled water source or a small radiator, you
could wrap about 30' of 1/4" copper tubing around the motor and
circulate water or antifreeze through the line. But as noted in
other posts, cooling the outside of the motor might not be as
good as blowing air through the case.

-jiw