Ever wondered what the various electric guitar finishes are all about? For example my Strat has a classic aged Surf Green Nitro finish:
Check out this cool article from Fender which discusses the history, science and various finishes Fender use on the guitars.
Both historically and today, a lot of science is involved in finish coatings for musical instruments. The substancesthemselves and their various application methods and combinations are enormously complex. And it definitely bears remembering that these finishes are applied to products fashioned from once-living organic plant matter; namely, wood. Wood is a substance that moves and changes with climate, treatment and age, as do the finish coatings that are applied to it.