Metal Bonding

[HEEP]

Alright guys, I need something that will bond two pieces of metal together in a spot that I can not weld. It is for a body mount. I have cut open a channel where GM did not put a nut for my year car. I want to make sure this mount is there and when I take the car back apart for final paint/powder, I need that nut captured in that spot. I have already made the captures, I just cant get any welder gun or torch in the area.

Of course, JB Weld has come to mind, but I am just wondering is there something better?

Thanks,
HEEP