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Question:  Can I paint over rust?

Answer:  Yes you can, however there are several steps to take in order to make painting over rust easier.  

1. You should remove all of the rust that you can using a steel or nylon wire brush.
2. Clean the surface using a Tri Sodium Phosphate/water mixture.
3. Paint the surface with a liquid product called Rust Arrestor by Insl X or a product called Rust Destroyer.  Both of these products will chemically convert the rust to a paintable surface.  The rust will then not bleed back through whatever paint you end up using.
4. After the product above has dried,  you can apply one or two coats of paint to the surface.