I used the filler for repairing plastic bumpers to repair the cracks in the wheel on my '50. Afterwards I sprayed it with 2 pack paint. Hasn't cracked in the last 4 years or so. This is the only picture I can find that has the wheel in it.

1950 Chevrolet 3100 (occasionally working) truck:https://c2.staticflickr.com/6/5490/30684982201_6dc479d18d_c.jpg
1928 Chevrolet AB National Phaeton: https://c4.staticflickr.com/6/5573/30137792083_42886d30a4_c.jpg
1932 Austin Special Sports: https://c8.staticflickr.com/6/5793/30116567183_1520e67c4d_z.jpg