My understanding is that most aerosol spray paints don't adhere well to bare metal and will chip off very easily. I sprayed a frame once and took moderate time on the prep and waited several days for curing but still found the paint chipped very easily. I discovered later it was best to simply rough up the existing paint and then clean it with acetone, or similar solvent, and then paint to give the spray paint something better to adhere to. I've never even heard of a clear primer, so I'd be interested to hear how it works, but I suppose it might be difficult to see how badly it was chipping until you started seeing corrosion on the steel tubes.

Anyway, sounds like you have some more googling to do. This has been discussed ad-nauseum on the internet. I looked a bit and found a decent thread about painting a bare frame on our very own beloved BF.net: http://www.bikeforums.net/archive/in.../t-144045.html