just a note on the rustoleum rattle cans. That stuff don't play well with others. Ya gotta strip it off if you decide to paint over it later. even if you try to cover it later with more rustoleum, it tends to bubble up.

You can however, spray as many coats as you want, as long as the cure time inbetween is minimal.

I learned this the hard way, painting some snowflake wheels. Cost me at least ten hours work before I figured out what the problem was.

Now, I avoid rustoleum. Quite franky, if ya gotta use rattlecan, Krylon is a better product.

If you are really looking for a quick ( cheap ) fix to stop the rust from spreading, grab a couple cans of epoxy ( appliance ) enamel. That will work just about as good as anything.