Auto body repair & detailing: 82 camaro bumpers, camaro z28, wet sand

Question
I have an 82 Camaro Z28 that i will be repainting. My question concerns the flexible bumpers used on this car. The front bumper has cracks all over it, not tears right through, but just spider web like cracking of the paint. How do i fix this, can i sand down to bare plastic (or whatever material there made of) and then spray a certain type of coating over it to prevent future cracking. What if the cracks go right into the plastic? I did a 79 Firebird a few years back with the same problem, and i primed and painted with the same primer as the rest of the body, not a flexible primer or anything special, and it started to crack again within a year or two.  Any help would be appreciated, as I do not want to buy a new bumper. Thanx

Answer
Wet sand the bumpers down to the original material. Duromix makes a filler for you problem. you will find it at your local autopaint supply store. Yuo apply it like a filler and sand it off. works real well. Fillow directions on the tube.


            Hope this helps


          Brian