Once I remove some of the rust, I have pits in the metal. What's the best way to fix them and smooth the surface? Many (many many) years ago, bondo was the go to to fix this problem. I would hope that there is a better solution today.
No matter which method you use...You MUST get all the rust out of the pits in the metal. Or neutralize it before putting anything over the pits. If you lead em...You have to get the rust out ...Period...The tinning butter/lead wont stick to rusty metal. But, all is not lost. A skim coat of a good polyester filler like Rage gold/extreme will do just fine and is quite acceptable as a permanent repair (as long as the rust is properly removed/ prepped). If its gonna take more than a thin skim of filler to fix em. Cut the rusty metal out and weld in a patch panel. If you do it right you can simply metal finish the area and not need filler at all...Good luck!!!
Go to the por15 web site.. They have a special filler for filling pits... Also buy a fiberglass etching pen it works really well getting the rust out of the bottom of the pits....
