I need to repaint a part of my radiator. I have already sanded the tarnished area with a grinder and a flapdisk but not the whole area (half of a fin) I'm getting ready to refinish, IOW most of the area still has paint but I removed it where it looked ugly (some burn marks).
Should I use an oil based primer (as I think that's best for metal) over the whole area and then just regular indoor paint?
The easiest way to prepare and paint your radiators is to: 1) scrape off any loose or flaking paint with a scraper. 2) starting with an 80 grit and working through to 120 grit sand any rust off and feather any paint edges smooth. 3) wipe the surface with a mineral spirit or paint thinner to remove any contaminates. 4) spray surface with an appropriate High heat spray paint in a can using partial overlapping strokes. Let each application dry as per instructions on label. No need for primer. And any brand will do. Some popular and quality names are Rustoleum, Krylon and Ace Brand spray paints. If there is hard to reach rust that can't be removed consider using a rust neutralizer. Spray this on any rusty areas and it will halt the rust from spreading while it turns it to a black color. It is now primed and ready for paint.
this is the best system to paint anything from plastic to stainless steel
Don't deviate or skip any steps.
1.clean thoroughly with acetone or MEK.
2.mechanically abrade with 180-240 grit (higher for smoother finish, but less lifespan, coarser for rougher finish but better adhesion) sandpaper
3.wipe again with acetone or MEK
4.rust convert any surface rust (on steel only) with 3M marhyde or corroseal rust converter
5.prime with any UMA primer like XIM400
6.paint with devthane 379 aliphatic urethane enamel.
Done!
I just did about 10 radiators in a house. I had mine sandblasted completely to remove everything, but if you're just getting rid of the rust that works too. Mine had layers and layers of paint from over the years that started chipping.
If you don't paint soon after sanding, it can start rusting again from the moisture in the atmosphere. I went to Lowe's and got Rustoleum White Gloss Protective Enamel (here) and sprayed mine, it worked like a charm. You go through a lot of paint though, but I didn't have a sprayer at the time. I recommend spraying over brushing unless you aren't too worried about getting the nooks and crannies.
