smooth bumper cap

High Build prime..sand....high build prime...sand= Smooth bumper caps. Thats how every single piece of painted plastic all my trucks has recieved
 
get out an orbital and sand yours smooth. get rid of the texture with 80, or 100 grit. That will knock out the texture quick.
then 220, 320, 400, etc as high as you want. Ive prepped all my stuff and had it sprayed. It came out tits, and my painter said he had to rough some of it up, and I only took it to 500 wet.

Save your money, and get out the sand paper for a few minutes!