How To Weld Rusty Metal. Thoroughly clean the surface to be welded grind file dress and dry. Because rust cannot be stopped from affecting metals and their welds there are some things you can do besides using a different weld technique to help prevent rust formation.
But here are some more useful techniques that people can utilize when welding sheet metal. To ease the process it is advised that you first clean your metal from any dirty contaminants such as rust dirt oil and grease as much as possible. Rusty metal can be welded although the welding process can be difficult and is not preferred by professionals.
Keep the amperage turned way down hit it briefly and try to build up the surface with globs until you can weld to your own weld.
Chop it channel it section it and you will have cut most of the rusty sections away. And maybe the epoxy would result in a more rustproof seam. The first step was to cut out the rust. The majority of the people will use one of three standard electrodes.