Painting composites

I would like to paint some composite material made of carbon fiber and Aeropoxy (PR2032) and was wondering what is the best kind of paint to use for good adhesion. My guess would be enamel, but perhaps there are special paints specifically formulated for CF composites? Also, should the surface be sanded to provide a tooth for adhesion?

I paint mine as per a normal panel. The only things you need to make sure of is that ALL traces of release agent are totally removed. And yes, the surfaces need to be keyed for adhesion. Just as per normal though, nothing special required.

The one thing you do have to watch out for, is if you are doing a panel like a bonnet or something and it hasn’t been post-cured, then you might start getting print-through into your finish if it softens up in the sun.

What’s a sure fire way of removing a petroleum based semi perm release agent, such as frekote 770nc? Will a normal wash with a dishwashing detergent take care of it?

NC770 is THE worst to try to paint over. I always had fisheyes even after washing/preping the parts. I’m not certain but i think it may contain teflon or silicone in NC770… very bad for paint adhesion.

Well technically Frekote shouldn’t transfer, it doesn’t contaminate your part. If it does then you’ve applied too much to your mould. And no, no Teflon or silicone in Frekote, it’s polymer based.

The way I clean my parts is to first wash it with warm soap and water, and then give it a wipe with acetone or MEK.

Good to hear. I have painted quite a few parts now that I’ve used frekote as the release agent for, and I’ve never ran into any trouble with it… However I do go through the whole 9 yards for prepping: sanding, washing with a detergent, and eventually a petroleum solvent right before spraying the clear.