Wet sanding edges on painted metal

I’m (spray) painting the metal tops to some older Hori stuff (SC2 sticks, Namco’s with chipped paint/rust spots, etc.) and once I let it dry and go to wet sand the paint smooth, I have problems. Any spot that’s flat and surrounded by other flat metal I can sand smooth easily, but any edges, whether the outlying edges or around the button/joystick hole, it sands down to the primer. Am I over-sanding, do I just need to paint those areas thicker, or is there something I can do to temporarily fill in those areas so its smooth and I don’t tear down to the primer or surface? I’ll post a picture of what I’m talking about when I can.

Did you use a sanding block while building up the primer?

Tips—
#Once the primers all built up and level, it’s more difficult to cut to the metal. Make sure you’ve a sufficient amount of paint before cutting and buffing.

Most spray paints are pretty weak and spray thin when compared with automotive paints, making wet sanding more precarious.

#When you cut to bare metal, on a piece you’ve put many hours into, you can just q-tip or tooth pick the voids with a dab of paint and lightly wet sand some more. (Those edges will be covered anyway so…)

#Spray paint can take anywhere from a week to a month to fully cure and harden (Patience is a virtue).

P.S.
Are you wet sanding by hand? What grit? What brand spray paint? I recommend Duplicolor and Rustoleum Professional (tall silver can).

I use a block, usually with 1000 or 1500 grit sandpaper. I use Rustoleum metal primer, and the paint is usually in whatever color I like that can be found at Lowes.