Regarding the hot iron damaging the pneumatic cloth - John Tuttle
mentioned that he thought a 150 degree iron would damage the rubber on
the pneumatic cloth.  Products made of rubber are heated to 260 to 350
degrees to cure or vulcanize.  It is doubtful that an iron set below the
boiling point of the fresh hide glue would do any damage to the rubber.

Bob Lemon
Lemon's Player Piano Service
Sacramento CA