Hi Everyone,  I see many are talking about pneumatic cloth.  Dave Ramey
sells some very nice material for striking pneumatics and air motors:

  https://dcramey.com/Other%20Items.html 

No, it is not cotton backed but that is of little importance.  I have
been using it for quite some time now and it handles well.  He also
sells the companion glue for the material.

Try it, you will like it!

Ben Gottfried - Ben's Player Piano Service
Richfield Springs, New York
http://www.bensplayerservice.com/