Comments about Evercoat Polyvinyl Alcohol:
Hard to spray over the repaired surface, because it dries into a cloggy mess. Probably a trick to it, that I don't know.
Once you get it on the repair, it dries into a film that does seem to promote curing. You can peel some of it off, afterwards, but you have to sand or scrub off the rest.
There must be an easier way...