liquid steel

I don't know, there are some adhesives by 3M designed for non-structural body panel installation. Clearly JB weld is not the appropriate adhesive.

You might shoot him this link so that he does it at least "kind of" right.

http://www.3m.com/product/information/Automix-Panel-Bonding-Adhesive.html

For me, I'd weld them in, and like others have said, if you can't do it right, find someone who can.

Knowing your limitations is a sign of maturity.

Regards,

Joe Dokes