Thanks for all the help so far!
I am using "NOW" brand # 21201 Aluminum colored spray paint. I am laying it over 3 coats of sanded automotive primer. It's warm and sunny where I live, so I dont think that temperature plays a factor. The plastics that I am working with are sintra and PVC.
Does the metallic paint need more time to cure than regular paint? I am giving it like 2 days before applying the masking compound. Then I am allowing the masking compound to cure overnight before adding the next coat of paint.
I am using Hobbico brand MasterMask liquid masking film.
I think I'll go pick up one of those erasers and try that out!!! Thanks!