Primer really doesn't protect against rust without good paint over it. I use ' epoxy primer ' over metal if I'm not going to topcoat it anytime soon. You will have to have a compressor and gun to apply real epoxy primer. Contrary to what labels may say, real epoxy primer doesn't come in spray cans, it would ' set up ' in the can. And, epoxys that I am familiar with contain issocyanates, which is deadly. If I get even a slight breath of it I can't spell ( shevy ) and I feel like this>