I'm patching up the C post of my 2CV. The plate is of 0.9mm thick which is similar as the original. Later I'll weld the sill rail end on top of the repaired area, so it has to be strong. So I'm thinking about making a bigger patch and plug weld it inside, then seam weld the repair plate on top making it a double skin structure. But I'm also concerned that it could be a rust trap...The treatment I can think of is to use weld through on all surfaces of the plates. Any suggestions?
Cheers,
Chang
Cheers,
Chang