Responding to the Small Bird Box Bellows repair question:  If your
"small singing music box" is of snuff box size (approx. 2.5" x 3.5" x
1.5" height) and the pop-up variety, then the manufacturer most likely
was using a "zephyr" skin material for the bellows covering, along with
6 paper gussets attached to the inside of the material in order to
insure proper in-folding when in use.  If there are no gussets, then
even with a tiny bellows the covering will blow out improperly.

Your repairman must also check, clean and/or replace any aged or damaged
inner pallet or 'flap' valves and air channels.  Any dust or particle
remnants will surely lodge in and block the valves from seating cleanly.
Same will be true of the whistle valve chamber which I would also advise
opening, cleaning, re-assembling and re-sealing.

If the item is somewhat larger, then it is possible that a thin leather
of between .005" and .008" was used.  What I usually use for these
medium-sized bellows is what is termed pneumatic "pouch" leather by
most.  Though thin, this material is still quite porous, so original
(and modern) manufacturers treat(ed) this pouch leather both previous
to or after gussets are attached and the skin glued to the bellows.

This treatment consisted of the application of a diluted rubber cement
solution which was brushed or 'worked' into the outside (smooth)
surface of the (outstretched) skin quickly with no excess, then left to
air dry.  Usually, one application is sufficient.  Simple talc is then
applied and worked into the surface to neutralize the cements sticky
attributes.  Patterns can then be cut, gussets applied (to the inside
surface) if not already, then on to the wooden bellows framework.

In the end, your bellows need to be as tight (sans leaks) as possible,
yet supple and free floating as possible.  The spring driven clockwork
motor that drives a small bellows is not like a constant, unforgiving
electric motor that drives no matter what.  Your bellows should be as
near to effortless, free floating as possible, with only the reservoir
and its retention spring being the only counter-force.

There are great reference photo's and details descriptions of numerous
techniques for all these in the book "The Mechanical Singing-bird
Tabatiers" by Geoffrey T. Mayson (2000) ISBN-0 7090 6303 2, which
I believe can be found via:

  Nancy Fratti (Panchronia Antiquities), Canastota, NY.
  E-mail <musicbox@dreamscape.com> Tel. 315.684.9977

There are many suppliers of "Zephyr" skin and "pouch" leather, including:

  Columbia Organ Leathers, Columbia, PA.
  Tel. 800.423.7003/Fax 717.684.4428

  American Piano Supply Co., Clifton, NJ.
  Tel. 201.777.3600/Fax 201.777.0481

  Schaff Piano Supply, Lake Zurich, IL.
  Tel. 800.747.4266/Fax 847.438.4615

Best of luck and Happy Holidays!

Jere Ryder
Jere & Steve Ryder - AutaMusique, Ltd.
Summit, NJ