The Aeolian Grand style 17 is a vacuum operated machine, unlike the later Orchestrelles. The valves in this machine are actuated by small pneumatics rather than pouches. The material on these pneumatics was a thin white leather-like material. It was mostly destroyed, so complete replacement was in order. First the old material was sanded off.


I built the jig shown below to help covering these tiny pneumatics. It holds the two pieces of the pneumatic solidly enough to allow manipulation at the right separation, parallel to each other.

I used extra thin kangaroo leather from Columbia Organ leathers to recover the bellows. They were applied with hot hide glue.

Three sides can be glued with the pneumatic in the jig

The leather is wrapped around to complete the fourth side

The pneumatics are creased to flex inward at the ends and out at the sides. A small piece of pneumatic cloth is used to hold the pneumatic closed at the "hinge" end.