Radiator prep?

[Tr3aguy]

OK so the radiator is repaired and returned but I need to paint. I bought radiator paint but I have a little surface rust on the side bracket not on the fins. What is the best prep method to use so my paint does its job.

Do I need to strip or just convert the rust and neutralize then paint over top of that?

Any suggestions?

I could upload a photo if that would help!

 

[Darrell_Walker]

I would remove as much with a wire brush/sandpaper as you are willing to spend time on, then apply something like Naval Jelly or Oxisolv, then paint.

I've used the rust converter type paints before, and generally they work well, but I don't know how they would handle a hot area like the radiator, and it will never be easier than now (with the radiator out of the car) to do a proper job.

 

[CJD]

Do you have a sand blaster? Don't blast the brass, but if you want paint to stick...forever...nothing beats sand. The order after that is sanding with paper (if you can get to it), beads, wire brushing third, and solvents last.

The key to prep is eliminating any residual grease and oil. I would guess the radiator shop tanked it, so the oil should already be gone for you. After that, the important thing is helping the paint get a grip. Sand etches the metal the best....but often is too aggressive for many materials. There are also etching primers...for under hood parts, I often finish paint the black parts using a good etching primer. It gives a nice satin finish...or can be topped with a gloss paint.

Just my preferences...

John