CA on tuning pins

[Billbrpt]

In a message dated 5/12/98 10:53:50 AM Central Daylight Time, rscott@wwnet.net
writes:

<< Bill,
 
   I read a posting of yours in the pianotech archives of a week or
 so ago regarding tightening tuning pins.  There is an old Henry F.
 Miller grand at our church that I have been maintaining on a 
 volunteer basis for several years.  About 6 pins in the bass are
 so loose that they let go at the slightest CCW torque.  The rest 
 are also a little loose, but still serviceable.
 
   I have been considering CA glue applied wholesale to the base
 of the pins without removing them.  I was going to use thin CA.
 Your posting talks about CA applied with the pin removed, any
 it refers to medium or thick CA.  What do you think I should
 use?  Medium CA on the 6 very loose pins (removed), or thin
 CA on the entire bass section without removing the pins?
 
 Bob Scott
 Ann Arbor, Michigan
 Detroit-Windsor Chapter, PTG
  >>

You can try either method.  Using water-thin CA glue as "pinblock dope" may be
effective in treating this problem.  There are those who would never consider
doing this and say that rebuilding is the only solution.  Repinning with a
larger pin in the problem area is also another more generally recommended
remedy.

However, I believe that there is a time and place for any and all kinds of
techniques so even though pinblck replacement or repinning are generally
better solutions, I will tell you what I think some of the other alternatives
are.

I really don't recommend any of the "pinblock dopes" but that is my opinion.
There are those who use them and say that they work.  Using water-thin CA glue
or Epoxy thinned to a watery viscosity with acetone have been effective for me
many times. They are most effective if you can combine the use of the
restorative chemical with driving the tuning pin in further.

First, look to see if there is enough pin to drive it further.  Then look at
the bottom of the pinblock to see if there is room for the pin to be driven
futher there too.  If you can see the end of the pin easily, don't drive it
further because you won't be driving it into any new material.  Also try to
make sure you are not driving into a pinblock that is delaminating.  If so,
you may only damge it further.

I suggest applying the CA glue liberally into the plate bushing area and
before it has set up entirely, drive the pins.  Remember to support the
pinblock with a jack and block and to put old sandpaper between the block and
the pinblock just in case any CA glue leaks through.

You can also apply CA glue to the holes from the bottom of the pinblock if you
can get someone to help you turn the piano upside down.  I would suggest doing
this first, before driving because it will size up the hole and the wood into
which you will be driving thus making your pin tighter.  There are situations
in which this can work very well and you can get many more years of tuning
stability by doing it.  It will certainly not work in every case however.

The other approach is different entirely.  You remove the pin, apply medium or
thick CA glue in the hole and to the tip of the pin.  This insures that you
really are getting the glue into the entire gripping surface rather than just
the very top or bottom of it.  If the pinblock is fragile, repinning the whole
thing with larger pins may just cause it to delaminate in a short time
afterwards.  This is why some repinning jobs fail.  Repinning with epoxy or CA
glue however puts some restorative material into the areas where there is
deterioration.  These kinds of jobs hold up with much more certainty.

  If you are using a restorative fluid while repinning a grand, you must be
aware that some of this fluid will be driven out the bottom of the hole and
onto the block and jack you have supporting it.  Someone on the List once
suggested saving your old sandpaper for this to use as an insulating gasket.
CA glue in particular will very quickly bond to your support block and you
don't want to have to break it loose afterwards.

Many pianos which develop loose tuning pins do so because the pians were never
driven in sufficiently in the first place.  Using water-thin CA glue or Epoxy
thinned to a watery viscosity with acetone combined with driving the pins
usually makes for a very effective fix.  The pins seat in new, unused material
and the restorative fluids seep into the worn, rounded out area of the tuning
pin hole and tightly grip the pin.

With either of these chemicals, you must use eye and breathing protection.

Bill Bremmer RPT
Madison, WIsconsin