[ Ref. Craig Wiley in 210312 MMD ]

Craig, I didn't know a Wurlitzer band organ had a separate vacuum pump
because I've never done one, but I believe the answer to all your
questions is to experiment. Sand off the old glue until you have clean
wood. Glue a piece of scrap leather to it with freshly made hide glue
and let dry a day or two. Then try to tear it off. It should be very hard
to tear off leaving fuzz behind. If it peels off clean, you have trouble.

You talked about gluing leather to leather, perhaps you are splicing?
You will definitely need to sand the skin side very well. Experiment
again with scrap leather. Try a couple different methods to find out
what works best.

Most of the pumps I've done were pressure pumps. Some were lined with
thin leather or cotton twill with stiffeners in between the lining and
leather. I use a material from Tandy Leather called bag liner. It's for
making women's hand bags stiff. It comes in different weights.

I usually size both sides with hide glue. Then glue to either the liner
or leather if no liner was used. I seal the inside of the leather with
PVCe glue, being careful not to get it on the area that it glued to wood.

You will save yourself a lot of trouble by experimentation. I find
leather to be so much easier to work with as opposed to heavy bellows
cloth.

Randy Hayno