When restoring 19^th century and early 20^th century pianos, getting appropriate wire for stringing has been a problem for decades.
Present-day piano wire is too stiff and its tensile strength is higher than necessary, causing a very low percentage of string load and therefore lack of tone quality.
Some Dutch and Flemish piano restorers combined forces in an attempt to find a suitable material.
Samples of original strings were sent to several wire factories.

Soon two main problems appeared:

Minimum production quantities in any wire factory are 1000 kgs per gauge.

Between 1834 and 1900 the steel industry went through a period of rapid and dramatic change.

Parallel to this the piano industry was constantly striving for a bigger tone. It would not suffice to produce just one type of wire to do all restorations. Two or three types of wire, each 1000 kgs per gauge, would obviously lead to impossible amounts.

The expertise of a metallurgist was sought. He made an inventory of the qualities needed, putting the emphasis on 1860 - 1880. The next step was to see if there was a type of wire, already in production, that would fit the description.

One type of steel emerged from this: A stainless steel consisting of:

Fe	-	approx. 73%
Cr	-	approx. 16 - 18%
Ni	-	approx. 7-9%
Mn	-	approx. 0.6 - 1,1%
C	-	approx. 0,1%

With the following qualities:

Average density 7,90

Tensile strength 8 - 18% below usual pianowire(see "Wire Data").

Elasticity-modulus 190 kN/mm2.

Very even diametre.

Extremely good tuning stability.

Material contains hardly any impurities, contributing to a very pure tone.

The wire allows low percentages of string load, so in spite of its relatively high tensile strength, stringings of very early pianos are also possible with very good results. The reason for this: A different crystalline microstructure, causing all these different qualities.

And do not forget: This wire is stainless, offering clear advantages both when stringing and in the long run.

When stringing grands there is an optical advantage, too.

Although the wire presents a lovely sound straight away after the first few tunings, the wire develops its full richness of tone quality after several months.

After many years of testing, our stainless steel piano wire has been used with great success where standard wire could not save the instrument. Many Erards, Pleyels, Broadwoods, Collard & Collards, Bechsteins, Bösendorfers, have Pure Sound strings, are being played on regularly, sound lovely and stay in tune amazingly well.

Pure Sound piano wire is virtually the best possible alternative for all straight-strung pianos and grands from 1830 onwards. Also many cross-strung late 19^th century and early 20^th century pianos have string speaking-lengths which are too short for standard piano wire.

We have solved many problems in bass stringing with 20^th century instruments, especially on the lowest monochords. When pure sound wire is used instead of usual piano wire, the lowest notes become more full and explicit.

Another very useful application is stringing change-over areas where thick wire has not enough length, therefore becomes too stiff to produce an acceptable tone. Simply replacing them with pure sound wire of the same gauge solves the problem.
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