OK so apparently I was too cryptic...
I have a pillar to replace due to rust and instead of pulling 2 outside panels and at least 2 whole windows, if I could use an structural adhesive to replace the rusted parts of the pillar, without needing to pull all those other body panels, that would be nice.
If I cut out the bad metal and lay a 1/4 piece of flat steel over the top with the adhesive, I am thinking it would be stronger than the original. Add in a few braces and maybe a few more plates in important areas, maybe with some rivets for good measure.
Throw on some POR-15 afterwards and its as sealed, if not better then it was originally.