Robbie the Metal Master at Work!

His explanation of what he does is excellent, anyone who can turn a wrench could understand.
That little spot welder/puller dohicky is pretty cool, I've used one with nail sized weld on studs and a slide hammer, but the keys and bridge are perfect for the slightly thicker than tinfoil that the newer stuff is made from. I can't imagine all that single wall stuff accessible from both sides too. I always had other people around to do bondo, and used 2 colors of primer over it to detect and sand out the tiny stuff.
For awhile I had a shop with anchor points in the slab and a collection of steel bits to pull uniframes around, mostly did old Volvos and they were no fun at all, harder to straighten a frame than a lot of trucks. When I gave up that rental the landlord was happy to see all the concrete repair, little did he know most was from anchors I pulled out.