as a matter of fact i did that at work today. so from that particular job i dont have any longevity reports to give. a piss can is a good temporary fix. you will have to worry about that parts that are coated over the original coat of paint. that tends to be the first to flake off. if you are just repainted some sporatic patches your best bet is to sand the very rough spots with sand paper, scuff (light sanding to remove the "slickness" of good paint/clearcoat so the new paint can bond) the painted areas and go from there. the best and most reliabe set i have ever done was for a spare, in which i took it to a car dealership, paid a random technician 10 bucks to sandblast it, and then piss canned it. i still have that rim, and although it has some scrathes on it, it scratches up just like an OEM rim