Krylon gloss white (not Fusion) seems to be adhering extremely well without primer. I'm doing 1500 grit wet sand between coats. I love the way it looks after Micromesh polishing. I'm very happy with the color and the luster. It's perfect.
The parts I have sprayed over primer are not so durable. Krylon primer seems to be enabling a layer of weakness more than anything. I have test parts painted Krylon white with and without primer. It's real easy to get a fingernail in these primed parts and take a chunk of white out of it while the non-primed parts require a lot of effort to make a chip in them.
I'm planning to go ahead and get the primer off of the parts. I'm not sure yet how I'm going to do it. It's a 1997 Bandai plastic model. I guess I can't use chemicals for this job.
David Kennesaw, GA