[RyanS]

I would recommend the 1/4" solid core McMaster-Carr Polyurethane Belting. We used it on our robot this year for the first time.

http://www.chiefdelphi.com/media/photos/33401

For all of the people that have had problems with their welded joints failing, I have a feeling that you are not melting the Polyurethane Belting enough. We tried welding with a hobby hot knife and soldering Iron with flat tipped blade, but found that it was only melting the edges of the belting. For the belts on our robot, we used the the blue flame of a candle (the orange flame will char the belt leaving ugly black marks). We then took the hot knife and smoothed the polyurethane that squeezed out of the joint (My mom calls this frosting the joint).

As others have said there is no need to buy a jig. We made our own jig by putting a 1/4" slot in a piece of 1/2" thick aluminum stock. The aluminum acts as a big heat sink too.

We bought a considerable amount of extra belting because we had heard of failures. Fortunately we have had no joints or belts break.

Ryan