[SSsssteamer]

There are chemicals that convert iron oxide (rust) to iron phosphate, and that stops the rust. Rust Mort, Ospho, and others do a good job at stopping rust. Of course, one has to clean the area and remove all loose rust before applying the rust converter. Once applied and the directions have been followed, one can paint over the prepared surface with regular paint. I have used them for over 50 years with great success.