Im about to put on a sissy bar--Ok now how do I prevent rust on the screws after a while--seems like the biles I look at that have one are getting rust on the screws

 

If it is the screw heads you are talking about, either go with chrome, or clean them off with alcohol and spray them with a clear lacquer.

 

I agree that chrome is the way to go but even some of the chrome ones rust after a while. Many of them are cheap junk from "offshore" and it's hard to tell just by looking at them but they seem to rust overnight.
I've started using stainless steel when I can find it.

 

I use stainless steel screws. The heads can be buffed to a chrome like finish & they can't rust. Any marine dealership carries stainless hardware so I have no problems buying whatever screws, bolts or nuts I need.