Using a bed liner in a can, my two sons Lucas,16, and Isaac,11, just upgraded the bed on our 1980 Plymouth Arrow Pickup. Try finding a plastic bed liner for that! The kit they applied transformed the looks of this old truck.
As with any painting project, preparation for a roll on bed liner is the hard part.
The boys first pressure washed the bed, then went over the surface with a regular automotive spray cleaner. This is a cleaner made for paint preparation or bug remover. Acetone is the usual cleaner choice. You must use a cleaner to get the wax off. You want to clean first. Otherwise, you likely just smear around whatever grease and wax are on the surface. It doesn't get taken off with the sandpaper.
Then the boys sanded the entire surface. We used 100 grit because that's what we had, but use a coarse grit.
Next we washed the bed out. One more time over with the cleaner and then the bed's ready for the roll on bedliner paint.
Take the tailgate off if you can. Ours won't come off! So we were extra careful with masking around the gate.
Mask all edges and fasteners or fittings you don't want coated. Masking is important, but not nearly as critical as when you are spraying. Mask the drain holes and other holes where bolts are removed. This bed liner in a can stuff is hard to clear from those holes when it dries.
We did the top of the bed rails, so we had to cover the sides of the truck to prevent splashing down the sides of the bed. Most people put a regular rail cap on the bed rails so you don't need the liner material there anyway.
Applying the material is the easy part. We used a 3 inch wide paint roller with a thick nap and foam brushes. We got cheap rollers and foam brushes, so we could pitch them and avoid clean-up. Get a cheap pan liner too.
Apply the paint in all corners and on edges first with your brushes. Once that's finished, apply the coating to the vertical surfaces starting on the front . It's a roll on bed liner after all... Next start at the front of the floor and work your way back. Depending on the shape of the floor, you may need to use a brush on some on the floor. Finish with the tailgate. Now let everything dry for the recommended time and then re-coat. We let the first coat dry overnight.
For the second coat, you may need an extension pole for the roller so you can stay out of the bed.
Touch up any spots you missed and then remove the masking tape and you're ready to go. Cure time varies but allow about 3 days for the cure. Now you're ready to use your new looking bed liner, custom applied by you.