Rob Buckingham talked about the nice purple cloth from Schaff Piano.
I wonder if this is the same stuff at was originally sold by American
Piano Supply Co., number 451354B?  This cloth is Nylon coated with
polyurethane and is about .005 inches thick.  It seems like a very
nice cloth.

What bothers me about using this cloth is that they recommend using
PVCE glue for proper gluing.  I have used this cloth on rebuilds which
other glues were used.  I should say that I haven't used it for
rebuilding the key pneumatics.  Only on the motor and tracker units.

This cloth seems great but I don't have any long-term track records
on its durability.  The only other thing that bothers me is using the
PVCE glue.

I have used this same cloth material on two air motors, using the
traditional hide glue, which seems to work.  I should say that it does
not adhere as well as the old cotton cloth when used with hide glue.
If you pull on the material from the side, then it has the strength,
but if you pull directly above the glued area it pulls off easily.

If the material is not stretched properly in the corners or has air
bubbles under the cloth, the glued area could fail prematurely.
I have also found that the hide glue in a bottle has a better bond than
using the hide glue crystals used in a glue pot.  I don't understand
this.

When I do a rebuild of the key pneumatics, I almost always make new
ones from new poplar wood.  I break so many of them with the removal of
the old pneumatics, and the cleaning up of the old wood takes so long,
that making all new ones from scratch makes the job go faster.  If the
rebuilders are making new key pneumatics, then does it matter whether
the cloth is glued with the PVCE or the traditional hide glue?  Of
course, you would always use hide glue to glue the key pneumatics to
the tier boards.

Any comments about this (good or bad)?

Pete Knobloch (Tempe Arizona, USA)