ship paint

Yes. Just give the primer sufficient time to cure.

One thing with that. I find it's better to use a primer that's not close to the finish color, so use gray finish over white primer. Otherwise it's really hard to tell if you have good coverage, until you photograph it. Then you'll be disappointed...

I like white primer, except for airliners.

You might want to check out Krylon's Fusion for plastic.  It comes in white as well as grey and makes a great primer.  Dries rather quickly and does a great job covering.  Also, a lot cheaper than hobby shop primer.  I use either their grey or white Fusion brand for nearly all of my primer jobs.

Bob