Airbrushler - Yes, the can states that you can top coat over the primer.. Just doesn't say what kind of paints can be used as a top coat.

I think this stuff is intended for painting an old tractor or something that had previously been covered with a layer of surface rust. After airbrushing or sand blasting the rust off, you would then spray this stuff on, then top coat it. It is weird stuff, and it certainly does look like actual surface rust, after you apply it. It takes a long time to dry too. It has been drying for over 2.5 hours, and still has a tackiness to it. Don't ever confuse this with Red or Red Oxide Primer like I did. This is a different animal.