Lexus plastic panel refinishing

[Sarastro]

I need to refinish the "roof spoiler" on my friend's Lexus. The problem is shown in the attached photo. The piece appears to be a transparent but dark plastic. It has some kind of coating, which has failed and is flaking off.

What's the best way to refinish it? In most cases, I would wet sand and buff the plastic, almost like a newly painted finish. I have done this before on fogged-up headlight covers, with success. But this surface is awfully rough, and I'm afraid that any sanding that would remove the flaking would also scratch the underlying plastic too severely, and then I couldn't sand/buff out the scratches.

I'm open to all suggestions. Thanks for any help you can provide.

 

[gonzo]

Perhaps the clear coat is peeling and pulling away from the painted surface below. Prep area being careful not to blow through paint layer and apply a couple coats of clear coat. If painting is needed, choose one for plastics and more specifically, bumper paint which is flexible. Alternatively, wrap the part.

 

[mezy]

just need to sand the whole thing back, then plastics primer adhesion promoter. before painting, there is no need to try finding a specific type of paint.
just repaint it in the correct colour, base and clear coat. all modern paints are flexible,
Just look at a bent metal panel the paint will still be intact.

 

[Sarastro]

Thanks. It looks to me like the plastic is colored black, no paint, but there is a clear coat or a lacquer that is failing. I was unsure about sanding it and clearcoating it again, but you give me some confidence to try that. I think I'll start with a small, less visible area and see how it goes. It will be hard to leave it looking worse, I think.

The car also had a damaged bumper, which I fixed. My pal had obtained an estimate for the bumper, and the guy at the body shop said he'd fix the plastic panel at no additional charge. So, it can't be a huge job.