#5: Common Problems of Piano Restoration

How can a nearly 200 years old piano be brought back to its initial appearance? Can one hope to restore even its original sound?

The aim of my purchase of this fortepiano by Daniel Dörr from c.1830, is certainly to get as close to its original state, while keeping as much as possible of its original material. In this blog post, I will present you to some common problems one faces when restoring an old piano. Many of these defects are less visible, but crucial to address to regain a stable structure and prevent further damage when the piano is restrung and played again.  

The pin block

One of the main concerns in any piano restoration is the pin block; the wooden block where the tuning pins reside. While it is not visible because of the veneer, it is hidden “behind” the keys, under the tuning pins on the photo.

After 200 years, it is almost impossible that the original tuning block still keeps all the tuning pins properly tight. Cracks in this wooden structure may easily cause the pins to lose their hold. This will cause the strings to pull themselves out of tune due to the tension exerted at its intended pitch.

A piano which cannot be tuned, or which does not stay reliably in tune, is useless as a professional instrument. To ensure a long life for the piano after the restoration, the pin block must therefore usually be exchanged. Repairing an old pin block is not seen as a reliable solution for anything but museum instruments.

A cracked soundboard

Another well-known problem with old pianos, are cracks in the soundboard. This, too, is caused by changes in the wood due to age, temperature and humidity changes and maybe even more severe damages. Even here, the Dörr has been rather lucky – but a few minor cracks are slightly visible as long streaks along the grain of the wood.

In this photo, you can see that the old, and slightly too thick strings have been removed, and the playing action (keyboard) been taken out of the piano. We can see the soundboard clearly, and vaguely recognizes some slight cracks. As these cracks will prevent the soundboard from properly carrying the sound created by the strings when playing, they must be mended! We will return to this point after the majority of the wood work is completed.

Structural weaknesses

In many cases, old pianos suffer seriously from major structural problems. Luckily for the Dörr piano, it has a healthy and sturdy construction, which is largely intact.

But one weakness at the tail end of the piano had already been mended, probably in the 1980s. However, although mended in a less visible place, the repair does not look very pretty:

Sorry about the bad photo, but can you see the extra plank with screws inside the tail end? This part will soon be removed, as it has been repaired by the cabinet maker by inserting a narrow piece of plywood into the tail of the rim (that is the white-ish streak).

Woodworm traces

We humans are not the only ones who love trees. Think of all the species that live in trees and that even eat the trees!

Unfortunately for the pianos, some little creatures keep living in dead wood – and love to munch away on pianos while their favourite tunes are being played. (Don’t you think?) The woodworms eat little tunnels in the piano, visible to the naked eye as holes and traces in the surface:

These parts of the piano legs have been sanded down and cleaned, but the woodworm traces are still visible. To make sure that no little worms or their eggs will wake up and continue with their piano meal, the entire piano will travel to Stuttgart very soon and visit a heat chamber where it will be heated to about 63 degrees C. This should kill everything that still might live or hibernate inside!

When the piano returns from the ‘anti woodworm treatment’, the wood restoration can continue. As you can see, there are large wooden threads on top of the legs, which makes it easy to attach them to the piano.

Imagine what it will look like when it’s all made pretty again…

Veneer damage

As you have probably noticed already, the surface of the Dörr piano simply looks bad. The obvious damages to the veneer, are the most visible defects of the piano. Even though it may not directly influence the sound, it is a complex job to repair and restore the piano’s visual appearance.

Luckily, I have found the right man for the job, and I will show you the beautiful work of cabinet maker Wolfgang Bischoff in the Black Forest next week!

Christina Kobb, 12 May 2023

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