Center Pin Lubricant

[kiddell@freenet.edmonton.ab.ca]

On Wed, 12 Jul 1995, Barrie Heaton wrote:

> It seems most of you seem to prefer using wood alcohol to
> recentre your flanges.  I am fascinated I am assuming that you
> only use alcohol on relatively new bushings as the old bushings
> before 1950 would have been glued in with animal glue.  The
> solvent for animal glue is spirits.  So I would imagine the same
> problem arising with the centre pin lubricant ie., bushings
> falling out.
>
> Does the alcohol not effect the glue in new flanges as I am led
> to believe that a crossed linked pva glue is used and pva is
> water soluble over a period of time.  So in using alcohol on
> centre pines are you not creating problems for the technician in
> the future.  A colleague in Scotland tells me that a major
> American manufacturer recommends alcohol on its centres is this
> true?  if so is it a ploy by the manufacturers to shorten the
> life of the piano therefore increasing sales.  Or is it just that
> I've got hold of the wrong end of the centre pin.

Barry,

The major American piano manufacturer that I work for has two methods for
treating tight action centers.

1) a 1:8 silicone/naptha solution: 1/2 pint silicone to 1/2 gal. naptha
apply liberally to all action centers

2) methanol/water shrinking solution: 75% water 25% methanol, to be
applied to those centers that didn't respond to the first treatment.
Drying time is 4-6 hrs., using a hair-dryer speeds it up.

I have used both techniques, with some success, on new instruments. The
silicone/naptha treatment is by far the more effective, but messier
(DON'T spill any on a new finish!) Silicone also does strange things to
lacquer, and if you have silicone in an area where you spray (or even do
touch ups) it causes fish-eyes and running.

On older instruments, both treatments are less effective, and repinning
or re-bushing is the best long-term repair.

I have not had any trouble with glue loosening the bushing after these
treatments, but I haven't pulled and checked every center, either. These
techniques are for quick repair, not as long-term solutions.

(Any chance that alcohol is a single malt?)           (-8

Rob Kiddell
C.A.P.T.
Edmonton, Alberta Canada