[Arran]

It's doubtful that the stripper would take the varnish of the windings in the Variac, even if it did manage to get on them. The varnish used on wire is a very different kind from the types used on boats and furniture, it's very difficult to remove even when you want to remove it, I think it may be phenolic based. The good news is that you can still find blue hammertoned paint, although you may have to look for it, I believe that Rustoleum makes one version of it, too bad about the lettering though.
This is one of the reasons why I keep cans of stripper and solvent near or on the floor. It's strange how it would eat through the container, I've had can's of stripper sit around for years and never spring a leak. Was it a plastic or a steel container?
Regards
Arran