Epoxy Pinblock Repair

[cpstout]

David and List:

on Thu 23 Jan 1997 18:30-56 you wrote   ..."I have a customer with an
old grand with loose tuning pins.  The pinblock has been treated with
some sort of pinblock treatment.  Would an epoxy repair of the whole
pinblock be possible after the piano has been 'doped'?"

Yes, it is entirely possible to fiberglasss resin (hereafter called
epoxy) a whole piano, grands included.  In fact I have never done a
partial pinblock in any piano although I am sure it would work.  The
trouble is that usually the whole pinblock is in about the same shape so
it is a matter of 'all or none at all'.

You asked about a grand piano that had been 'doped'.  In fact, I have
never done a piano that had NOT been treated with some kind or other of
liquid tightener.  Just be sure to get a 22 caliber rifle cleaning brush
that is stiff- bristled, use a variable speed electric drill and clean
up the t-pin holes as good as you can, vacuuming out all the 'gunk'.

The only way I would attempt to epoxy a piano is described in my first
posting under 'cpstout'.  In that message, I recommended blocking up the
usual foot or so with pin block jacks; covering that support board with
a piece of thickest felt; and then lay a piece of aluminum foil over
that.  Even then some epoxy may make a 'puddle' on the bottom side of
the pinblock.  That's the bad news, but the good news is that it chisels
off quite easily even when hardened.

Take a small dixie cup, pour in about 3/4" of fiberglass resin, add two
or three drops of hardener and stir with a hammer shand or something
like that.  You can then let the dixie cup form its own funnel and pour
in about 1/2 the hole full..  Take your oversize tuning pin (at least a
3-0 or even 4-0s) and swab the tuning pin itself with epoxy (I use
q-swabs).  Drive the pin into the block until you can feel the pin go
harder - i.e up against the 'coller' left at the bottom of the hole
where the factory stopped its pin insertion.  Note:  I found the best
results where when I did NOT attach the new wire the first operation.
Without having strings to bother with, you can then back the pins out
about two (2) turns.  This allows for all coils to be formed separately
on a 'dummy' tuning pin; inserted over the pins; attaching the beckets
and closing with a pair of pliers so the beckets can't come out when
tightening wires.

Again the bad news is that it certainly does take extra time, making all
the coils on the dummy pin.  The good news you eliminate perhaps just as
many operations as when a new pinblock is installed, not to mention that
fiberglass resin is a lot cheaper than a new section of pinblock.

My first posting brought some questions on how and why epoxy seated pins
turn "so nicely, almost as good as a new pinblock - better than overly
tight blocks found in certain new pianos". My only thought here is that
each tuning pin moulds its own threads into the hardened resin, thus
permitting a smooth feel in tuning.  So far the resin has lasted 27
years in my first piano.

I have done perhaps 8 - 10 pianos in this manner and, to the best of my
knowledge, all are in continued use.  Let me add that this is about the
ONLY way to do antique pianos, particularly verticles.  If anyone on
pianotech cares to call over the (ugh!) telephone at (602) 899-1751, I
would be glad to visit personally about this method of repair until
about April 1st when I return to my home in Holyoke, Colorado.   (970)
854-3328 is the number there.

			cpstout@concentric.net
			(a.k.a. 'Clancy' Stout)
			Nebraska Chapter
			Holyoke, Co and Chandler AZ

P.S.  Another paragraph below  oops!











Continuing with the actual steps to use, do about 6 - 8 pins; mix a new
batch of epoxy and continue.  After about 1 hour or so, back each pin
out about two turns.  This allows the finished pin to free travel w/o
'bottoming out' against the epoxied residue that fills the hole.  This
stuff is hard and pins will not penetrate it - just jump back up again
which is no fun I assure you!