Recovering the valve pneumatics



This is my Aeolian Grand 58-note player organ. It is a Style 17 according to the sticker on the inside, the latest date I've seen anywhere on it is 1899. It is basically in decent untouched, unrestored condition, but it apparently was home to quite a menagerie of rodents at some point. There were both freeze-dried mice and squirrels inside, as well as all the chestnuts you might ever want. I've decided to have a go at restoration myself, and I have, of course, almost immediately run into problems I haven't seen in the pianos I've worked on. I'm hoping that some of you generous and knowledgeable souls will lend thought.

In this picture you can see one of my poor mouse-eaten pneumatics that opens a bass pallet valve. A leather hinge was glued to the beveled surface you can see here and then the leather came out of the slot and was glued to the outside of the square wooden block at the back. Note the tongue that engages the valve--it is glued and nailed on the outside of the leather, ie it is put on after the pneumatic is leathered. More on that later.

Here is an end view where you can see the brads driven into the end of this very narrow (3/32") piece of wood.

Here's a side view showing the moveable part of the pneumatic and the side of the tongue

Here's a view looking down on the end of the pneumatic. The hinge material and the leather on the top of the pneumatic were eaten on this one. One issue is that when the leather sides are glued on there is essentially no glue surface at the point where the bevel meets the block

So, I've started making a new set. The rodent damage is so extensive that most of the pneumatic boards are gone--you can see what was inside the box!

I'm using 3/32 aircraft plywood for the boards, which is really nice to work with-- 5 plies, no voids, the plies put together with phenolic resin glue so they shouldn't delaminate with humidity. That's one of my new ones in a rough state on the top. These pneumatics measure about 1 3/4" X 1 1/2", with an opening of 1/2".

So, here are my questions--

  1. Even with all new materials these leak like a sieve. Part of the problem is a bad piece of pneumatic leather which I'm replacing, part of it is the non-existent glue surface where the moving portion of the pneumatic meets the block at the back. I don't see any way to not have a pretty substantial "bleed hole" there either at the beginning or developing over time.

    Was this intentional? Or is it irrelevant to the operation of the organ?

    One can imagine different folding patterns that would provide a firm seal, do any of you who have worked on these do that?

    Is there some solution here that I'm not seeing?


  2. Reapplying the tongues that engage the valves looks to be a pretty problematic process. Because it is under stress when it opens the valve I suspect that the nails and the little reinforcing board are necessary to long term operation. I haven't been able to pound a brad in there, even with pre-drilling the holes because it is on the unsupported moveable arm of the pneumatic. I'm considering using this job as the excuse to get a 23ga pneumatic pinner. Is there a better/different way?

Thanks for any help, and I sure wish Richard Vance had worked on an earlier model!! What a web site, unfortunately his machine seems to be completely different from mine.