Rust Repair

I hate painting more than body work since something always goes wrong. If you can't sand away the rust pits, there are some products that eat away rust (Evapo-Rust), but you usually must dip the part in them, so see if anyone has had luck covering w/ a soaked rag and plastic. Many rust-converter products that will turn it to a hard black phosphate (?) and might work in the pits. If you sand too much, the metal will get too thin, and some pits may even go thru. A classic fix is to fill w/ lead, but wonder if that works on rust pits. Regardless, you should remove interior to get at the back side to treat that. Many rust-thrus are from the inside since they barely painted the metal there, like not at all at the tops of the doors. Any metal you weld in should be sprayed with high-zinc if it can't be painted later. You can use Home Depot cans or special "weld-thru primer". The main goal is to seal so moisture can't get at the steel. Rust doesn't really spread like cancer, it is just flaky so paint can't bond well. In theory it can be sealed and stopped.