Steve that is a simple fix. just cut out the bad part and find a rim that is rusted and cut out a piece the same size as you cut out of the first rim and weld it in. Grind off the weld and put paint on the outside an you will never know that it was repaired. On the inside grind it smooth and put some bondo on and sand smooth and drill a new hole for the valve stem. I know of a lot of rims that have been repaired that way and are used for heavy farming and some also for tractor pulling.