How to paint aftermarket pannel
 

I did do a search, but could not find the answer to my question, although it's been answered many times before. How do you guys prep an aftermarket fender that has the black e-coating on it?? I'm using base/clear as my paint. and was wondering if you guys scuff the black coating, prime and sand primer, and paint?? Or what is the correct process with certain grit sandpaper?? Any help appreciated.

me, i would strip to bare metal, clean with solvent, epoxy primer, sand , base & clear.

There are different schools of thought on prepping new parts with EDP coating. Some do like described above. Some (collision) shops will barely scratch the surface and shoot paint directly over it.
Our process is closer to what Gary does. We thoroughly sand the part with 320 grit until totally dulled. Then it's cleaned with solvent, followed with a coat of epoxy primer. Because PPG DP epoxy primer has a re-coat window of several days, the next day it gets a coat of high build primer on top of the epoxy. That holds it until it's time to sand and paint.

You can scuff up the e coat with 400.... leaving all the e coat on....then wash the panel with a water based cleaner...apply a coat of sealer...wait 30-45 minutes and refinish....NO Sanding....or you can do as above ....with the epoxy and high build primer if you a looking to block it out ,to make it lazer straight...