I play the musical saw although not very good.  I use a bow mostly,
but I differ on the point that it has to be dampened after each note:
it's not so at all, as you defeat the characteristic of its sound.

As soon as the next note/pitch is played the last note is gone
anyway, dampened or so.  It would be extremely difficult to make the
saw automatic: the tension and the positioning of the bow on the saw
has to be changed for each note.

How are you going to "wow" the sound of a note up an octave if it is
dampened?  Ah, Yes!  Use the sustaining pedal !

Steve Bentley
Vancouver BC