This story, we will go over the steps to smooth and prep plastic for painting. This information will not only be useful on bumpers, but you will also be able to use it for your dashboard, console, and just about anything that is constructed of the semi-rigid plastic used throughout your truck. If you have noticed, most of the premium trucks the factory pumps out have a smooth color-matched lower front valance. The factory knows as well as most of us custom folks that a color-matched valance looks much better than dark-gray plastic.
If you have tried to paint plastic before, you know it can be a bitch if you don't have the proper materials. You will need a high-build primer, since unlike metal or fiberglass, plastic is very hard to sand smooth. You will also need an adhesion promoter and a flex agent, so your paint will take a good bond and not be so brittle it flakes off when touched.
We followed along as Marcel Venable from Venable Koncepts smoothed out the lower valance on Jared Fullmer's '00 Chevy truck that we put on our cover in the Aug. '05 issue. This job was the last little modification on his truck before the shoot, and the paint was barely dry when Marcel started color-sanding and rubbing the part. If you have ever wondered how hard it is to smooth a plastic piece, read on and you can decide if this is something you want to tackle yourself or just pony up the coin and have a pro do it.