Yesterday we got in our two test materials, and they work like a charm when used together. I will say that we don't intend for our conveyor to go extremely fast like some people have posted, so YMMV for this setup.
The first is a
nylon mesh, with tiny holes. With a belt that's 6" wide, this stuff simply
does not break. After putting a sample in the vise and yanking on it, and on two glued pieces, all we found was that we were getting more and more tired of trying to break the stuff. It showed no signs of fatigue, neither on the material nor on the glued join. However, it does not grip the ball like I though it would.
The second material is a
neoprene mesh. It turns out that the mesh has 'teeth' that grip the ball ridiculously well in one direction, yet it has a worse grip than the nylon in the other direction...I wonder what we can use
that for... It's downside is that it is
extremely fragile.
But combine the two with some hot glue... and BAM a ridiculously strong, flexible, lightweight belt that is cheap ($40) and easy to make (don't stretch the neoprene when bonding the two though!). We also have a small sample of the two materials expoxied together, so tomorrow we'll see how well that worked out.
/edit
I should also add that we're using
this material as a tread to drive the belt.