Heres some mock up 4 by 2 wheels made from
ABS pipe and plexi discs.

I used a 2 part urethane resin that sets
in about 6 minutes.

Axles I made out of 1/2" aluminum.

The wheels in.

Heres three of the four molds my friend
Mark showed me how to make. These are out
of silicone.

Cool, a butt load of wheels.

Priming the wheels.