I replaced my convertible top last winter. After I removed the old top, I noticed that the frame had quite a bit of rust in places. So I first used a nylon brush on a drill motor to knock the loose and heavy corrosion off, then hand sanded with 150 grit followed by 220 grit sandpaper.
Prior to applying any paint, I cleaned the frame with POR-15 Marine Clean, then used their Metal Prep (etch) product. A thourogh rinse with plain water followed both of these treatments.
After allowing a couple of days for the frame to thoroughly dry, I brush painted it with two coats of POR-15 SemiGloss Black topcoat, making sure not to get paint into the pivot points.
When it dried the paint was quite hard with superior adhesion.
I would do the same thing again.
Edit: I also carefully lubricated each of the hinge pivot points with a needle-tipped oil bottle prior to installing the new cloth top.
Last edited by Norseman50; 08-01-2017 at 06:26 AM.