stretching wire

[John Delacour]

At 09:05 -0500 9/4/08, Ron Nossaman wrote:

>There is no appreciable (nothing is absolute, but it's 
>inconsequential) long term stretch, or creep, of piano wire below 
>it's yield point tension and under around 600¡F. So "pre-stretching" 
>doesn't pre-stretch.

Here we go again!  I wish I'd had you here last week when I was 
making a set of strings for two pre-1840 pianos using Paulello's wire 
types 1 and 2.  You would very quickly have changed your tune and 
your eyes would have demonstrated to you what repeated appeals to 
known science seem incapable of doing.

The _permanent_ stretching of the wire when the tension is first 
applied to the machine is significant, and the added stress of 
covering the wire leads to a frightening amount of extra _permanent_ 
elongation.  At no point is the wire subjected to anything like its 
maximum safe tension.  Whereas for Ršslau wire I work with a tension 
of 80 lbs, for these wires I go down to 44 lbs.

I am told by the restorer for whom I make such strings that they 
continue to stretch considerable when put on the piano and is is 
several _months_ before the strings are stable and sounding their 
best.

One complaint sometimes levelled at the famous old Poehlmann wire, 
which had a tensile strength higher than modern Ršslau wire, was that 
it stretched and took a long time to stabilize.  I am slightly too 
young to have experienced this but I have colleagues who are not.

I will finally do some experiments this summer and confirm once and 
for all the falsehood of your assertions.

JD