My question to Bernt Damm is, Does this absolutely need to be done
and what previous experience have you had ?

The crash value pouch leather is under extreme pressure all of the time
and must be able to withstand full pump pressure.  The pouch leathers
used in the regulator are usually in very good condition.  Connect a
hose to the pouches and blow as hard as you can and see if you can
split the leather under the 3 valve buttons.  If they don't blow out,
you can probably bypass this rebuild work.  If you have had previous
experience with rebuilding players and want to make sure that the
regulator is performing like new, then proceed with the work.

This procedure is described in the Vestal Press Technical Series No. 5
"Rebuilding the Duo-Art Reproducing Piano Mechanism", by Michael L.
Kitner.  I have had to split 2 regulators with very good results by
using a sharp carving knife.  This is like the one you use on
Thanksgiving for carving the turkey.  The entire edge of the blade
must rest across the length of the regulator without any gaps.

First remove the Solo and Accompaniment regulator pneumatics from
the main box by removing the screws and using the sharp knife to cut
through the old leather which is used to help in disassembly.

Now remove all other hardware from the outside of the box and lightly
sand the outside surface so you can see where the box was originally
glued.  You will find 2 seams where the wood grain doesn't match.

Don't assume that you found the proper seam to split, do some
measuring.  From the inside of the regulator, measure where you want
the split to happen and then go to the outside and measure again to
locate the proper seam.  Using a pencil, place a mark that points to
the proper seam so you don't get them mixed up.  Do NOT draw a line on
the seam.  The pencil mark will cover the seam and you will not be able
to scribe the line properly.

Use a sharp putty knife and hammer to place a small groove directly
over the seam to be split.  Do this around the entire box.  If you are
sloppy here, the wood may splinter in the wrong area and cause
problems.

At this point there may be more screws that are hiding under the old
leather which were used to align and glue the 2  regulator half's
together.  Remove these screws making sure that you find them all.
There may be 1 in the middle of the box.  If these screws are missing,
drill and countersink guide holes along the outside edge to help in
alignment and gluing later.

Recheck your scribe line at this point and make sure the box is going
to split in the proper place.

Lay your carving knife inside the groove along the entire edge of the
knife and carefully drive it into the wood about 1/32 inch.  Do this
around the entire outside of the box.  Continue driving the blade of
the knife further down inside the groove on each side.  Have patients
when doing this.  Don't rush or drive the knife in too far at a time.
You don't want the wood to splinter.  At some point you will hear the
wood releasing from the glue and the box will open.

When reassembly is done, sand the matting pieces on a thick piece of
glass.  These must mate perfectly to prevent any leaks between the
chambers.  I can not emphasize this next statement more: Only use hide
glue and pouch leather on the seam.  Glue pouch leather between the
split line so it can be rebuilt again in the next 60 years.

Note: The screws are only used for alignment and placing pressure on 
the seam while the hide glue dries.  Make sure that you use hide glue
on both sides of the leather when gluing the seam.

Pete Knobloch