This is on my 92 Camaro RS 3.1L 5 speed. Three months ago I bent my front right corner so, since I had work to do on that, I decide to bite the bullet and do major, major surgery due to rust out in my toe boards and door pillars. I had a guy put it on a frame machine to do a bit of straightening and now working on cutting donor patch panels for the floor, firewall, and right battery tray. In some cases, a lap joint will be needed. For example, I ordered and received a new battery tray but those do not come with the front extension from the battery tray to under the radiator core support. That extension is attached via a lap joint. I managed to salvage the one on my old battery tray since it doesn't have much rust or pitting. So, after this long story, what is the best way to rust protect lap joints so in this example in between the battery tray and the front extension? The new battery tray is EDP coated and the extension will be sandblasted. I am inclined to paint the extension with DP90 then Omni Single Stage but use a 3/4 inch sticky dot over the weld points to not paint on those. Then I plan to come back remove the dots and spray the bare metal with weld through primer followed by welding. Does this sound like the right way to do this?

Thanks.

 

Typically, a high zinc or "weld through" primer is used.