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Piano Reconditioning

Quite often, the thing that gets a person to contact a piano tuner, is that one of the keys has stopped working. And isn’t it always somewhere in the middle of the keyboard! There are thousands of glue joints in a piano action, which includes the eighty-eight keys. Fluctuations in humidity, especially winter dryness, causes wood to shrink slightly and glue joints to separate. Parts would then need to be re-glued. Dryness can also cause key bushings to squeak as well as keybeds. Piano friendly lubricants are used to remedy these problems. Pedals or ‘trap work’ are also popular places to squeak.
Excessive dryness is probably most devastating on the piano’s ability to hold a tuning. When this happens, most other problems are secondary. The tuning pins are driven into a pinblock, which has multi cross-laminations of hard rock maple. The tuning pins are usually about ten one-thousandths of an inch larger than the tuning pin holes. When the piano is new, this sizing provides just the right amount of torque for the tuning pins to support the twenty tons of tension in the piano. High humidity in the summer causes the tuning pins to get tighter in the pinblock. The wood expands and causes the wood fibres to be crushed by the tuning pins. In winter, the pinblock shrinks and the tuning pins are looser. As the cycle repeats annually, eventually the tuning pins are just too loose to hold the string tension. At this point, re-stringing the piano with larger tuning pins would be required. If the piano isn’t too old, and the strings are in good condition, it’s possible to just replace the tuning pins and keep the original strings. These are still costly options and depending on the age and condition of the piano, may not be worth it.
Sometimes an older piano is a family heirloom and parting with it is not an option. One way to keep an older piano going is to add c a glue(super glue) to the pinblock. For an upright, with the aid of a piano tilter, the glue is applied beside the tuning pin. It doesn’t actually glue the pin in, but when dry, the glue will take up the extra space in the wood and the pin is tighter. This will allow the piano to hold a tuning again.

@ 2017 Cyril Hull Piano Tuner-Technician