Below is a video of me demonstrating a player piano that I repaired.
I also work on old Pneumatic Player Pianos. The most common repair needed on these player mechanisms is replacing of the bellows cloth. Bellows suffer not only from wear but some insects will get inside and feed on the bellows cloth creating holes. Sometimes a repair can be made to the old cloth if the hole/s are small enough but the more permanent solution is remove and replace the cloth, the rubberized gaskets and any other area the wind can escape.
Pictured here I am working on my mother-in-laws player piano. This Baldwin was manufactured back in 1910 and has been in the family since. Unfortunately the player mechanism has not worked for over 25 years. Using a small gas torch I needed to use fire to “melt” off the old cloth and animal hide glue. It is a fairly fine line between removing the glue and burning the wood bellows.