[ Ref 120410 MMDigest ]
Well, I've finally dug into that set of pumping bellows (rebuilt ten
or fifteen years ago) and I've found a few answers to my questions.
The stack of felt blocking on the main bellows was apparently an
attempt to keep the bellows from holding down the internal valve disk.
(Instead of a flap valve, these units have a spring loaded leather
faced metal disk).
Besides the torn hinge end, I found some other holes in the bellows
cloth. What apparently led to the final failure of the hinge end was
rotted hinge cloth, although the glue job may have contributed too.
I'm not certain what the glue is, but I suspect hot glue sticks.
Warming it up does let me get the cloth off, sort of! It appears to
be a surface adhesion -- a swipe with a razor edge leaves what appears
to be clean wood. So now I have the fun of sanding and scraping and
then firing up the old glue pot and putting it all back together.
All the control bellows cloth appears to be in good order and holds
a vacuum well, so I am debating if I should dig into them at all.
They were working fine before the hinges failed. Any ideas?