Rattle can paint is not as good as spray paint, however, you can get the same paint the prof use in a custom spray boom. Eastwood even setup there cans with hardener.

Prep is the most important step.

1. Clean surface area with soap & water
2. Clean surface with degreaser
3. Clean surface with surface prep cleaner
4. Then start sanding/body work
5. Surface prep exposed steel with metal prep and etch
6. Clean surface with surface prep cleaner
7. Prime surface
8. Topcoat /wo sanding (if within same day)

If you skip this process don't surprised to see the paint
wash away within a few years.

I can send you photos of what your a quick paint job will look like with poor preparation.

Have a look at Eastwood product: http://www.eastwood.com/paints/2k-aero-spray-paints.html

I have not tried it but will in the future.