The process involves (I think) something along the lines of 20 coats of finish and coating. Those layers have to dry in between.
I was wondering about that. You can let stuff partially dry to a sticky finish between coats (a couple of hours) if you don't sand between, but I know nothing about producing a high gloss finish.
From my limited experience, I can say that I'm pretty sure super high grit sandings between each spray is critical to piano finishes. For satin, I think you still sand, just not as fine.
I don't think they need 20 coats, but maybe they do. For musical instruments I don't think they use that many, and they should have more abuse.
