[pianotech] Twist loses grip

John Delacour JD at Pianomaker.co.uk
Sat May 8 15:52:40 MDT 2010


At 08:09 -0400 8/5/10, Wiliam Ballard wrote:

>...So in this situation where I've run out of expertise, I thought 
>I'd dip into the communal well. Anyone have this happen to them? 
>Anyone know enough about the physics involve to suggest why the 
>standard benefit from twisting vanished overnight, while the twist 
>remained? IOW, should I trust 2.5 turns where 1.5 didn't work?

Twisting tubby or buzzing strings to try to revive them is always a 
gamble. The strings presumably sounded as they should when they were 
first put on and if they were properly made and nothing had happened 
to cause corrosion, they would sound as good after 100 years.

When you twist the strings you are relying on the flattening of the 
core wire at each end of the covering to hold the copper fast so that 
the twisting will tighten the whole coil of copper in between and 
(you hope) improve the contact of the covering with the core wire. 
If the flattening is inadequate, the copper will creep and lose the 
tension you have added.  The core wire will retain its twist, but the 
copper will lose the tension you added by means of the twisting. 
Besides that, there is the question of what sort of foreign matter, 
corrosion etc. may have led to the deterioration in the contact 
between core and cover.  By tightening the covering (twisting the 
core and relying on the flattening to hold the ends) you may be lucky 
and crush the oxides etc. enough to improve the tone, and more likely 
you will not, and the string will sound as bad or worse or never as 
good as it should.

You used the word "dead" to describe the strings.  That's the right 
word.  You have applied a temporary life support fix, but they are 
dead.

JD




More information about the pianotech mailing list

This PTG archive page provided courtesy of Moy Piano Service, LLC