Likely won't help. Screw will "saw thru" the dip. Then dip can help water to rust more, likely faster.
Use whatever to convert rust to anti-rust coating. Clean off big flakes only, not all of it.
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)