compression of punchings

[Bill Spurlock, RPT]

>If I recall it was Susan Graham who suggested tieing >sets of punchings inside
discarded panty-hose legs >and washing and drying them before ironing.
>I haven't tried that myself as I would think that might >remove too much of the
resilience from the felt.

That wasn't Susan, but another well known female technician. Trouble is, washing
punchings makes them fattter and softer, not denser. When quality woven felt is
made, it is compressed with moisture and heat. If the cloth later gets wet, it
expands, undoing the original forming operation. This is sort of like washing a
nice wool sweater in hot water. The wool fibers curl up, the cloth gets thicker,
and the overall size of the fabric bunches up, leaving the bottom edge up above
your belly button. (Don't ask me how I know.)

Try this experiment: Take 30 new balance rail punchings. Thoroughly wet 20 with
hot water. Leave 10 of these to dry laying loose, and dry the other 10 between
blocks of wood compressed in a vise. When dry, stack each group of 10 up
separately. The 10 from the vise will be thinner than the original (not wetted)
ones, and the 10 that were left to dry loose will be thicker by about 15%.

I agree with Michael Wathen that the object of compressing punchings should be
just to eliminate the initial settling that will happen anyway in 6 months due
to the weight of the keys and playing, so your regulation will be more stable.
My favorite method is just to slide all the front and balance rail punchings
onto a 1/8" rod with a stop block on one end and a sliding block on the other,
and leave them clamped tightly for a couple of days. When you undo the pressure
they'll be about 15 - 20% thinner.

Bill Spurlock