Keytops: Ivory or Plastic?
Sometimes a traditional material becomes unavailable and must therefore be replaced by a nontraditional material. Perhaps the best example of this is the replacement by plastic of ivory keytops. Although piano makers began using plastic keytops on cheaper instruments as early as the 1930s, and even on good grands as early as the 1960s, it wasn't until the passage of legislation in 1973 and 1989 banning the use, importation, and sale of elephant ivory that plastic became the de facto material for piano keytops.
The search for an alternative material for keytops may have begun, however, as early as the late 18th century. Harding lists several patents from 1788 to 1840 for covering piano keys with materials such as glass, enamel, bone, horn, mother-of-pearl, and porcelain. "It is unnecessary to enumerate more," says Harding; ". . . glass, porcelain, or enamel was to form a cheap substitute for ivory. The beautiful ivory itself was not thought to be as good as that which was plain and unfigured." Today, some makers describe their plastic keytops as synthetic ivory, and seek to formulate plastics with some of ivory's desirable properties, such as texture and the ability to absorb moisture.
Until fairly recently, buckskin was the material of choice for certain parts of the piano's action. Both the hammershank knuckle and the backcheck in the grand action were covered in buckskin, as was the hammer butt in the vertical piano action. Some manufacturers began using nontraditional materials to cover some of these parts as early as the 1960s and '70s, and there was a learning curve, to be sure. Baldwin's Corfam hammer-butt coverings became hard and noisy after several years' use, and the company routinely replaced them under warranty with Ecsaine, another synthetic material. In the 1960s, Steinway experimented with replacing not only the covering of the grand hammershank knuckle, but the entire knuckle, with a solid piece of hammer felt. After a few years of feedback about these experimental knuckles, Steinway returned to the more conventional buckskin covering.
Very recently, however, both the New York and Hamburg Steinway factories have replaced buckskin with Ecsaine for both the knuckle and backcheck coverings. As with the use of leather as a hammer covering 150 years ago, the problem was that the properties of buckskin vary from skin to skin. It was also difficult to find buckskin soft and supple enough to prevent action noise at both points. Ecsaine, on the other hand, has all the sought-after properties of buckskin, but is completely uniform from one piece to the next.
Most piano manufacturers now incorporate nontraditional materials in their cabinet parts. Laminated wood products, in place of solid or veneered wood, have become commonplace in both structural and nonstructural cabinet parts (as well as in soundboards). Engineered wood products such as medium-density fiberboard (MDF), and plastic trim find frequent use in place of wood in nonstructural areas. At least one European manufacturer of quality grands uses a paper-based material much like cardboard in nonstructural areas of the case, and I suspect that this material is used by other companies as well.