Hi gang,  Here is yet another couple of sources for polyurethane 
belting.  Both sources have material that is round in cross-section 
and in several diameters.  There are also V-belts and even flat belts 
available.  You can write or call for their catalogs or see them on 
the web:

  W. M. Berg, Inc.,        (a must-have catalog)
  499 Ocean Avenue
  East Rockaway, NY 11518
  Tel: 1-800-232-BERG
  http://www.wmberg.com

  Pyramid Incorporated
  PO Box 200
  522 North Ninth Avenue East
  Newton, Iowa  50208
  (515) 792-2405
  pyramid@netins.net
  http://www.pyramidbelts.com

Heat welding is easy if you use a simple alignment jig.  Experiment
first so you can get the hang of it.  Warm up both ends at the same
time next to the flame of a propane torch.  Keep at it until the
material melts and mushrooms out a bit.  Don't cook the ends too much
or you'll have dripping plastic and char.  

When the ends appear to be getting gooey, push the ends together in
your alignment jig and wait for things to cool off.  Trim the
mushroomed part of the joint flush with toe nail clippers.  You can
also make round belting out of polyurethane tubing in this way, you
don't really need the little barbed joiner thing.

If you have a distributor in your area that sells pneumatic regulators,
air cylinders and solenoid valves, they may have polyurethane tubing
for sale.  It's used a lot in that industry because the tubing doesn't
kink easily and is tough.

Dennis Mead