[BBray_T1296]

We cut the polycord to roughly 90-95% of the required length (2x distance between pulley axles, plus one full pulley circumference [or rather, 2 halves]) It really depends on how taught you want your belts, by which trial and error is the best method.

It was not the easiest method, but we fused our cords while totally loose, and once cooled, stretched and installed the pulleys by hand. On our 2012 robot, we had between 5 and 8 belts on a pvc tube acting as a very wide pulley. We stuck one end into the bearing block, and used leverage to stretch all the belts at once until we could jam the other side into its block.

I would recommend not fusing the belts while under tension, as the whole process is about as frustrating as it gets. Perhaps some reasonable method exists, but none that I am aware.

The idea of putting the pulleys in a slot is a good one, provided you can fix the pulley in their stretched position.