After a lot of research and discussion, my brother and I decided to try out a new paint job on his old Explorer. I had read where some guys had used 3M spray on rubberized, paintable undercoating as a primer to make the paint stick to the plastics. He finally decided to go with a desert tan top coat, so I pulled and prepped the small front cover, over the oil tank, to do a test run on.
I cleaned the panel with starter fluid and a clean rag to remove any oil residue, then applied the spray undercoating and let it dry for a few hours. I then used a clean rag to remove any over spray and applied a good coat of desert tan spray paint. It turned out really nice, the rubberized undercoating dries into a textured, yet smooth pliable surface, that the paint sticks to good. After letting the panel dry all day, I was able to bend and flex the panel with out any cracking or flaking.
Here is a pic of the panel; I'll post pic of the final paint job in a few weeks. We have a complete set of front end parts on the way and don't want to get grease all over a new paint job, so painting the rest of the atv is on hold until after the front end is rebuilt.