Key Top Recovering

Before the late 1940s, glue used in piano manufacturing was all water-soluble animal glue. Animal glue is easy to work with, very strong, and as long as it remains dry, lasts. Key top material until the advent of acetates and plastics in the late 40s and into the second half of the 20th century was usually ivory. Of course animal glue was used. As perspiration and humidity cycles over many years had its effect, ivory key tops were prone to loosening and coming off. Also, ivory is quite brittle so in the presence of children, ivory key tops were easily chipped and broken.

Modern keyboards are generally covered with various grades and qualities of plastic or plastic-like materials. An older keyboard, whether originally ivory or not, can be recovered with new material and make a great improvement in the appearance and feel of the keys. Sharp caps of wood wear down over heavy use so they loose their original height. In some cases, they bury between the white keys when depressed. Replacing sharp caps with either wood or plastic is a normal operation.

After recovering a keyboard, leveling the keys and setting a touch is necessary. Key top material is removed and the keys planed which makes the thickness slightly uneven. Leveling a keyboard makes the top of each key the same height within a couple of thousandths of an inch of its neighbor. Not doing this makes a keyboard look like a visit to the orthodontist is urgent.

When recovering keys, replacing the key bed felt at the same time is a good idea.