Want shiny paint on Polypropylene plastic

[Bean]

I am planning on repainting my motorcycle's plastics gloss black. They are polypropylene plastic. I want the shiniest finish I can get with a rattle can. I know the best way is to use adhesion promoter. I have the following questions though about the different options:
1. Do I need another primer over the adhesion promoter?
2. Will a filler primer work well to fill in blemishes over plastic on top of the adhesion promoter?
3. It is an street enduro type bike with the plastic fenders, assuming I go base followed by clear, will the flex of the fender/plastics due to vibrations put the base and clear coat in jeopardy of cracking?
4. Can you paint a clear coat over the bumper paint to get it nice and shiny?
5. Last question: do I wet sand the base coat prior to spraying the clear?

Thanks ahead of time. Great site.

[Dupli-Color-Specialist]

I am planning on repainting my motorcycle's plastics gloss black. They are polypropylene plastic. I want the shiniest finish I can get with a rattle can. I know the best way is to use adhesion promoter. I have the following questions though about the different options:
1. Do I need another primer over the adhesion promoter? Not unless you need to fix blemishes as mentioned in question 2.

2. Will a filler primer work well to fill in blemishes over plastic on top of the adhesion promoter? Yes

3. It is an street enduro type bike with the plastic fenders, assuming I go base followed by clear, will the flex of the fender/plastics due to vibrations put the base and clear coat in jeopardy of cracking? This is one thing that concerns me with your project. Yes the paint might crack and flake due to the flexing of the plastic. What I can suggest is to scuff up the existing glossy finish with a scotch brite pad. It is very difficult to get paint to bond to such a substrate.

4. Can you paint a clear coat over the bumper paint to get it nice and shiny?
Yes

5. Last question: do I wet sand the base coat prior to spraying the clear?
Only if needed. Meaning if there are any flaws in the base coat.

Thanks ahead of time. Great site.

I answered your questions within your post. Please see above in gray.

Glad you like the site.