The paint won’t adhere properly if there’s any dirt or waxy buildup on the surface of your car. [2] X Expert Source Chad ZaniAuto Detailing Expert Expert Interview. 2 October 2019.
Make sure to alternate directions as you sand, moving back and forth as well as up and down, in order to achieve a smooth, flawless finish.
To protect yourself from harmful fumes, make sure to wear protective gear such as a face mask and gloves while painting. If you’re using a spray can make sure to spray a bit of paint away from the bumper several times to clear out the nozzle. [7] X Research source
Each time you go over the bumper with the clear coat, overlap the previous pass by 50% for the best coverage. [11] X Research source
These connection points may be near the trunk latch, tail lights, or wheel wells, as well as hidden beneath bumper fascia.
The plastic types PP (polypropylene), PPO (polyphenylene oxide), and TPE (thermoplastic elastomer) will smear easily when ground or machine-sanded. Plastic types PUR (polyurethane plastic rigid) and TPUR (thermoplastic polyurethane elastomer) will turn to powder when they’re ground or sanded down. The brand doesn’t necessarily matter, but you should stick with the same brand throughout the entire repair process for the best results.
