As I have just mounted a new, original type M-B mild steel exhaust system, ordered from M-B (manufacturer Gillet) I share some pictures.
The system from factory, back in the sixties, was welded in all joints. They had a jig to place the whole length system in to enable this welding job of course.
Today, one must lift the system up, spot weld, bring down, weld fully etc. many times in order to obtain a good fit. I painted with flat black heat resistant paint, spray bottle.
/hans s