Seating strings

[Roger Jolly]

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Theory.

I agree that it is highly improbable that the string climbs up the pin.


However the pin can rise out of the bridge, due to hydraulics. As moisture 
is absorbed by the bridge, force is applied to the bottom of the pin, 
moving it upward.  This is the same principal as rocks appearing in a 
farmers field every spring.  Movement of water , pumps these rocks to the 
surface.   The string is held against the pin with friction, and rises with 
the pin.

For a number of years I have been using West systems epoxy as a driving 
fluid for installation of bridge pins.  The pin acts as a pump and forces 
the epoxy down the capillaries of the grain structure, making the hole/pin 
impervious to these moisture fluctuations.  The number of false beats to 
appear in bridges with this treatment is way less than no treatment.  Many 
of us have repaired bridges with epoxy, putting the epoxy in hole #1 and 
watching come out #2.

If the pin has moved upwards, then this can explain why a light tap will 
seat the pin and string, and be a partial cure for several years.  The 
hydraulics with begin to do it's evil work again.
   New pianos going to a very dry climate will exhibit shrinkage of the 
bridge, and can show a lot of falseness. Seating the strings by tapping the 
bridge pins cleans up a lot of the garbage, and lasts for a number of years.

I have had several long conversations with a Professor that specializes in 
soil Hydraulics, and does a lot of consultant work for major power 
corporation's , with regards to transmission lines.   The telegraph poles 
that you see beside the highway, leaning every way but vertical. Are moved 
by the following. #1 Hydraulics. #2 wind shear. #3 load.

He felt that my theory was a high probability.

Regards Roger.

PS I will keep tapping the falsies out. 

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