I never even knew such a thing as a "PCB Trace Repair kit" existed. I've repaired and modified hundreds of PCB-based things, and I just use jumper wires.
Offcuts of component legs are great, because they're short, stiff pieces of solid copper wire. You can do a neat job with them, and there are always lots of them lying around the workbench, though not so much in this age of surface-mount components.
For longer jumper wires, you can use hookup wire and stick it to the board with hot glue. Pretty is what works, and so on.
I don't know of any epoxy that can stand the heat of a soldering iron. It must exist, though, because epoxy is what sticks the copper to the board in the first place.