In any business knowing what to do is usually far more difficult then
actually doing it.  I have restored a few instruments so far and in
each case the flap valves have been traditional.  That is, leather flap
valves attached either with tacks or some kind of spring arrangement.

My current project is a Hinze piano.  The flap valves are made from
pneumatic cloth.  The bottom has 1/16" felt covered with cloth and the
top has cloth with wooden disks glued on.  You can see a picture here:
http://www.clarksmusicworks.com/MVC-122F.JPG

The "money" question is whether I should restore the flap valves
as designed, or just replace them with leather flap valves?  It is
interesting to note that this piano is only one of my pianos that still
works on it's original materials.  These flap valves are all crispy and
hard yet still functional.

Thanks ahead of time for you opinions and advice.

Dave Clark
Clark's Music Works