I used two coats of Rustoleum gloss black on my frame unprimed and touched it up in a few places where I made some changes such as welding in an added crossmember. Generally speaking the Rustoleum blends well with more than one coat BUT (!) it is pretty sensitive to temperature. For good results I recommend only using it at 70 F or above. In the summer when the garage was in the 90 F range the paint blended in great with extra coats and spot touchup, BUT in the Fall when the temperature went below 60 F it was a mess with major crinkling. It needs to be hot enough to drive off the solvent fast. Now I wish I had used a primer first but I won't know how it holds up on the road until I get the car running. I was over confident after the first coat on the frame, it looked good and dried fast so I put on another coat and that worked great in the Summer heat. Later when I added the crossmember in the cooler Fall I had a crinkling mess that I sanded down twice and painted three times until I just left it hidden beneath the body floor.

Don Shillady
Retired Scientist.teen rodder