While stripping the body for new paint ( I didn't strip to metal the first time 20 years ago) we found a couple previous repairs. Among them was a dent that was filled with bondo instead of pulling it out. The dent was in a spot where you can't get to the inside of the sheet metal and whoever did the work must not have had access to a stud gun. So for those who never saw one or saw one used here's how it works.
This is a stud gun which is sort of a 110V spot welder that attaches a stud to the body. The stud is loaded into the gun, pressed to the body, pull the trigger, and the tip of the stud glows red welding itself to the body.
There's a couple sizes of the studs but even the small ones will burn through most modern cars because the metal is much thinner than the old cars so the guns aren't used much by collision shops any more.The studs shown are the larger size which work great on old cars.
My buddy Jeff shows how the tool that pulls the studs works. He's been a body man all his life so he's got the technique down from working on cars like mine since they were new. Jeff's helping me do the car as part of a trade deal. So he's doing the exterior bodywork & paint which is really going to speed up my project since I can do the subframe, underside, and other things while he's making the car straight. We do jobs together and it works out well.