Painting Photoetch railing

Try some experiments. Cleaning with L thinner is fine, but try some different primers. It's the primer to metal bond that's failing. Getting paint stick to primer is usually not a problem.

Also try paint direct. That's how I usually go, but I also use enamels mostly.

Good luck and let us know the results.

Paint them with enamel. I've discovered that when it comes to painting PE parts, enamels seem to work better, for me at least. I have used acrylics to paint PE but prefer enamels. I should also state that when I paint PE I'm usually painting them with brush rather than spraying although there are occasions when I use the airbrush. I should ALSO state that I never primer the parts. I'm not saying that you shouldn't primer them just that I never do. If you haven't tried it you might also want to lightly scuff them with fine sandpaper just to give them a little tooth for the paint to grab onto. Of course, with railings, they will be easily bent and broken so scuff them gently. One more thing. Try washing them...if you haven't already...before painting. There may be chemical residue left over from the etching process or even oils from your hands...if you aren't wearing gloves...that may be hindering good paint adhesion.

You could try "etching" the railings by washing them with white vinegar and rinsing with clear water.

This will provide "tooth" for the primer to adhere to...

All the best

Ray

You need a primer meant for metal.  Many primers for plastics do not work very well.  One help is to make a solution out of household bleach and immerse PE parts for just a very short period- five minutes or less.  That makes the surface a bit rough, helps primer stick. I use Krylon gray primer, which matches the color of many ships fairly well, so I don't need much color on top of the primer.  Usually the krylon primer works well enough that I do not etch- merely clean as you have done.  Yeah, I get a few small chips but easy enough to touch those up with small brush or toothpick.

And, when spraying primer do not put it on too dry.  Although you want a thin coat to prevent webbing, you do not want the coat to be too dry, which inhibits adhesion.  Get up close, but put down a very quick spray.

I saw a reader tip in FSM that suggested soaking PE parts in tire cleaner to get the release agents off.  I generally paint via airbrush with enamels and have never had an issue.

Groot