But don't try this on a new vehicle with factory paint, because the manufacturers have figured out ways to paint cars using very little paint, and then bake it on so it will last. A modern truck might only have 2.5 to 3mm of paint on it, so any polishing could thin the clearcoat layer and ruin its UV protection. But a restored classic or custom truck can usually benefit from being polished out.
A typical repaint job will be between 13 and 25mm thick. And while a 13mm-thick paint job will look a lot better after polishing, a 17-25mm paint job will not only look better but last longer if it is polished out. That's because thick paint expands and contracts at a different rate than the metal underneath when placed in the sun, and as a result it eventually cracks. You may not even notice the little cracks until rust forms underneath and opens them up.
So how do you tell if your truck's finish is thick enough to polish out? That's easy. Just pick up an inexpensive magnetic paint gauge at your local automotive paint store and test your paint. The further up you can pull the gauge before its magnet becomes unstuck, the thinner the paint is. You can read the gauge on the side of the magnetic base. Paint will usually be thickest in crevices and thinnest on tops and hoods.
Assuming you have enough paint on your old hauler, you can make a marginal gun finish look great, and you can make a good professional paint job look even better. Here's how: Start by washing your truck carefully using a good car wash solution and water. Any grit or dirt left on the finish could make scratches that are hard to get out. Next, it's a good idea to tack rag the car as an extra precaution, and perhaps even use detailer's clay and water to remove any impurities in the paint.
To start the process, fill a bucket with clean water and put a couple of drops of dishwashing detergent in to help soften the sandpaper's edges. Now place several sheets of 2,000-grit sandpaper in the water and let it set for about half an hour. Wrap a piece of the sandpaper around a sanding pad and begin sanding. Never use microfine paper with just your fingers without a pad, because you will make grooves in the paint if you do.