My friend just repainted his, and here's what he did. He used 600 grit I believe -- sanded down twice with that. Then the car was sanded down using 1000-1200 grit sandpaper, twice. Then, the dents were grinded down to the bare metal, and sanded, then filled, and sanded with 1000-1200 grit. Repeat those steps [without the grinding] until the surface imperfections are pretty much gone. Then the car was wet-sanded using 2000 grit I think once, then sprayed with primer, sanded, primer, sanded, etc.. until as close to perfection as possible is obtained. Then the car was wetsanded twice with 2500 grit until it was as smooth as a babies bottom. Then paint. That should give a near perfect exterior.

I don't know if that's the professional method, or if it's too involved, or whatever -- it made the car with the new paint look perfect. That's what matters.

 

Hmmm, I don't know if you actually read my post above, but it's best to avoid any kind of power sanding device when trying to get the car to look perfect. My friend did all the prepwork himself, and sanded the car entirely by HAND. Never use power tools as you will see the resultant through the final coats of paint. By hand sanding, you get a contouring effect that's unmatched by any sander. This will give you a flawless exterior.

What were you wanting to know about prep-work? Did I answer your question?