How to Wet Sand Primer

The process of painting a car involves many different details, and the more detail-oriented you get with the job, the better the paint job will be. Having a solid primer coat on the vehicle is crucial to getting a smooth, flat paint job and you have to wet sand it to make sure there are no scratches in the final finish as the result of bodywork. Wet sanding can take several hours to do, and it varies based on the size of the car and the paint job.

Instructions

1

Wet down the vehicle completely using the hose. Fill up the bucket with water and place all of the sandpaper in the water to soak. Spray the black spray paint onto the vehicle to lightly dust the primer with the paint. The goal is not to change the color of the primer, but to lay down a guide coat for sanding.

2

Wrap the 320-grit sandpaper around the sanding block. Hold the block in one hand and the hose in the other, with water slowly running out of the hose. Sand down the vehicle using the sanding block, making sure to keep the surface wet at all times so as not to gum up the sandpaper. When the paper stops being effective, swap to a fresh piece of 320-grit. Sand the body until all of the black paint is off of the primer.

3

Dust the car lightly with the spray paint again, then switch to the 400-grit sandpaper. Repeat step 2 with the 400-grit paper, then with the 500- and 600-grit until all of the sanding scratches are out of the finish and the primer is flat.