I'm a flight simulator tech working on military simulators.We used to use a
visual system that would really fry certain parts of the circuit boards.
I'm talking enough crispy critters that at times we had to cut out a hole
about the size of a quarter or slightly larger and rebuild the board. We
used just regular 5-minute epoxy which we mixed in some circuit board
fibres we scrapped off old garbaged circuit boards. That filled in the hole
and by the next day everything would be good and dry so we would use the
minichine attachment of the Pace kit to grind/sand that area flat with the
board again. We would lay out the circuit traces with more 5-minute epoxy
and once that was dry we would use "Print Kote" conformal coating to seal
the new traces to the repaired area. If there were any solder pads that we
replaced with didn't cover those over the coating. The same for where we
had to overlap traces. We would use a very small iron to solder to those
areas or we would use hot air. It all worked great and we never had any
problems. It may seem a bit of a chore to do it this way but when you get a
10" x 10" board that is worth (supposedly) $37,000.00 then you don't mind
spending a bit of time fixing one.

Cheers,
Lawrence