On my last paint job I used automotive paint from Sherman Williams. The primer is amazing. Its their epoxy based primer intended to be used on heavy duty vehicles like dump trucks. I havent had a scratch yet that has penetrated the primer. The paint on the other hand has chipped and scratched fairly easily. I believe this has to do with commercial frames being baked. I also was in a time/weather/temperature crunch and rushed the clear coat. I only applied 4 light coats. 10 coats (or fewer heavier coats) might make it more durable. That said, the finish was excellent.