I recently split open a very similar design sander that had a dud switch. I was surprised to see how much sanding dust had filled the internal passages I had to use a pick to dig it out . Maybe yours is affected similar?
When does the sweating happen? I grew up in MA in Worcester county and remember the garage floor getting dripping wet from temperature changes and condensation. If that’s the case epoxy really won’t help I think
How about an entry chamber of sorts, so when you have to open the big door, all the dry air doesn’t go out the door along with temperature swings.
PS, oh yeah, forgot to mention how nice your shop is!
I have had some luck spraying a solvent like carb or brake cleaner to soften it up. Or you could put the vice on a fire or bbq to cook it good enough to the same effect.
So, I have found a Proto 1421 hammer that looks to have an offset wooden handle.
Was this a thing? The photo looks like it may have been made this way?