Leaded Joint example...

Here you can see how early car manufacturers used lead (instead of Bondo) to fill in roof joints. Notice how sanding (file) marks are still present in the lead. More importantly, just how thick the early paint jobs had to be to cover these scratches up.

 

Image:

Konica T4

40mm f1.8

Fuji 4791 duplicating film.

POTA developer, 12 Minutes.

Done