I am currently re-building a box pump from a Weber grand Duo-Art
(the motor-driven square pump containing four exhausters and a central
eccentric crank). It is my first one, and there are a few things
I have not seen before, and are not mentioned in the books or on
Piano-care, or in MMD Archives, so can I have some advice please.
First, regarding the flap valves, there is a narrow strip of thin felt
nailed lengthwise across the holes, on top of the fixed pouch leather.
Is it to reduce "slap" noise, or what, and should I replace it (or
leave it out)?
Second, there are wads of what looks like horsehair glued inside each
exhauster across the opening end (i.e. opposite end to the hinge) of
both the fixed and moving boards. Thus the cloth takes a gentler curve
back into the folds. Is this just to relieve the cloth, or what?
The original stuff has disintegrated somewhat and the fibres found
their way under the flaps where they lodged and increased the leakage
from the already stiffish flaps. Should I replace these wads? If so,
with what? Would 1/4-inch felt be okay?
Finally, the flaps have steel (or plated brass) strips folded over and
rivetted for the coil tension springs to attach to. What is the best
way to re-fix these strips? I have ordered some 1/16" brass rivets
which I intend to cut down; will they do the job?
The mechanics of the pump seem okay: the bearings are ball bearings,
but any other advice regarding these beasts would be appreciated
(I have the Mike Kitner booklet, and Reblitz).
Thanks in anticipation,
John Farmer, UK