Surface rust can be treated with sandpaper. A good air compressor is needed if you want to use a dual action sander. I use an electric 7 inch disc sander from Harbor Freight because it quickly cuts down to the bare metal and saves time. Another method is to use the 4 and 1/2 inch polycarbide disc on an angle grinder. It is designed to strip paint and works great on rust too.
Epoxy primer will help keep rust from returning and spreading once you get rid of the rust as suggested above.
I am sure that most on here will say that sandblasting is the only way to go. It seems the best but is dangerous to your lungs unless you have the right equipment. I don't have a compressor large enough to do sandblasting.
Metal that is rotted with rust needs to be cut out and patch panels used for repair.
I think you need to post some pictures so peole here have a better idea of what kind of rust problem you are dealing with. Then you will get more responses.
Last edited by Lugnutz; 05/23/2012 1:54 AM.
