Bob:
It was my understanding that there are now many ways of "plating" that are essentially deposition of like-upon-like material.
I know I've read many media articles about various in-vacuum techniques to build up materials (seems like that was one of the space station objectives long ago -- combine vacuum and zero-g to produce arbitrarily perfect layers of materials for composite skins, electronics, and high-tech metals).
Maybe I'm just wildly optimistic, but wouldn't it be nice if you could build up weak spots in materials that were detected with ultrasound examinations, rather than lowering pressurs or welding a patch on?
Tom