X2 on mr.48chev's dent puller comment. Harbor Fright sells a "Stud Welder" for a hundred bucks. (Some people call it a pin welder.):
https://www.harborfreight.com/stud-w...kit-61433.html
It works well but tends to pop its circuit breaker a lot. I surgically removed its circuit breaker, realizing my breaker in the wall will protect my house. I haven't had a problem with overheating the stud welder, which is what the on-board circuit breaker was meant to protect against.