When a piano is being regulated, rebuilt, or restored there are several details that frequently are overlooked in the process. One of the first things to be noticed when approaching a piano for the first time is the way the key tops look and feel. Often you can get an idea of the condition of the rest of the piano just from your first impression at the keyboard. The keys are the pianist's connection to the piano. The keys must have a pleasing appearance and must feel good when your fingers touch them. There must not be too much friction, or the action will be sluggish; however, the keys must not be so loose that they wobble from side to side or make unwanted noise that would detract from the music.
At Vanderhoofven Piano Service we are trained for advanced key repairs, and have equipped our shop with all the materials and tools necessary to achieve top-quality key work.
If you have a good-quality vintage piano, the chances are good that the white key tops are ivory. Ivory usually comes in two individual pieces -- a head piece and a tail piece. The fronts are usually made of plastic, even on pianos with ivory key tops. Sometimes the key top will be one complete piece of ivory, but usually there will be a faint line where the head and tail pieces are joined together.
Ivory has several characteristics which make it ideal for use in pianos. As a pianist plays, perspiration from the fingers can build up and can cause the pianist's fingers to skate and slide around on slippery plastic key tops. However, ivory is porous, and the tiny pores actually absorb the moisture and draw it down below the surface of the ivory. Ivory also has the benefit of getting less slippery when wet than when dry. The structure of ivory gives it a "tooth" when wet.
Although ivory is ideal for use in making key tops, new ivory is no longer available. Replacing a complete set of key tops with legally sold ivory can be very expensive, costing several thousand dollars. Another option is the use of bone key tops for a vintage restoration project. If a keyboard has ivory pieces missing, it can be difficult to match the color or grain pattern of the originals with used ivory. With careful attention to detail when replacing individual ivory pieces, it is possible to do an outstanding job. After careful use of ivory bleaches and by spending a lot of time buffing and polishing the keys, the replacement pieces can be almost indistinguishable from the originals.
Chipped Ivory Repair
Sometimes a piano will have a nice ivory keyboard but have chips in the edges of the ivories. Previously, the only way to repair these chips was to replace the entire ivory slip. That still leaves the problem of matching the color and grain pattern of the originals. A new repair that has recently been developed is a process of filling in the ivory chips. This procedure uses a material similar to what a dentist would use when putting a cap or crown on a damaged tooth. The two-part epoxy makes a very solid repair that can be guaranteed to last. The epoxy can be tinted to blend in with the shade of the surrounding keys for an almost invisible repair.
New Key Tops
Even with careful bleaching and polishing, if more than a few ivories are missing, the replacements often stick out like sore thumbs. When a large number of ivory pieces are chipped or missing it is usually more cost-effective to replace the key tops with plastic key tops. This is a common repair, but it does take considerable skill to do a pleasing job. The repair is much more involved than just slapping on a new set of molded key tops. In replacing a damaged ivory keyboard with plastic, it is important to take pains to prepare the wood surface of the key so that the finished set of key tops will have the same height as the original ivories. The edges of the key tops should be straight and filed or routed exactly flush with the edges of the keys. Square notches and rounded edges and corners are a few signs of a job well done.
Black Key Replacement
When having key tops repaired or replaced, don't forget to replace the sharp keys also. Worn edges or gouges from fingernails can detract from the overall effect of having a new keyboard. On quality vintage pianos, the raised black keys were often made of ebony. Less expensive pianos would have used another type of wood that was stained or dyed black. Modern high-quality pianos still have ebony for black keys, but other pianos have black keys made of plastic or acrylic. Acrylic sharps come in either a gloss or a matte finish. Ebony sharps are much more expensive than plastic ones, but for a complete restoration, ebony is usually more appropriate.
The key bushings have a great effect on the way the piano plays, yet they are often ignored because of the time and effort it takes to replace them. The key bushings are designed to prevent noise from the metal key pin hitting the wood of the key. If the key bushings are too tight, the action can be sluggish, and the key bushings need to be carefully eased. If the key bushings are worn, damaged, or missing, the keys may be noisy and feel sloppy. At Vanderhoofven Piano Service, we use five different thicknesses of premium-quality bushing cloth and seven different sizes of precision-machined brass cauls to hold the cloth in place as it is glued. When the traditional hot hide glue has set, the key bushings are ironed for a precise fit on the key pins.
On an older piano, the key buttons will often be split or damaged or will start to come unglued from the key. The position and angle of the key button is critical to ensure proper function of the key. At Vanderhoofven Piano Service, we use specialized equipment for exact placement of the key buttons.
Balance Rail Hole Repairs
The balance rail holes can be greatly affected by changes in humidity. If the piano is experiencing very humid conditions, the wood of the balance rail hole may swell up, and the key will bind on the key pin. If the conditions are very dry, the balance rail hole will become loose, and the keys will wobble around and can add a lot of noise to the action. New pianos are notorious for having tight balance rail holes. Older pianos may have keys with damaged balance rail holes, perhaps from normal wear, excessive extremes in humidity or even from overzealous easing by a piano technician. If the balance rail holes are oval shaped, causing the keys to move forward and backward excessively, this is what the piano technician calls pulley keys (also known as chucking keys). In extreme cases, the key may need to be repaired by routing out a portion of the key, inlaying a new piece of wood, and drilling a new hole in the bottom of the key. Less severe damage can be repaired by resizing the existing hole so that it is again round in shape.
Action Touch-Weight and Weighting Keys
If a piano action is perceived as being too heavy or too light, there may be several reasons for this. Changes in voicing can have a pronounced effect on the way the action feels. Sometimes there may actually be a problem with the geometry of the action, or the action may not be well regulated, or there may be excessive friction in the action centers; any of these conditions can affect the touch-weight. This short paper cannot deal with all of the items that must be taken into consideration when evaluating the touch-weight of an action. If there is a problem with the action, it should be analyzed to find the cause of the problem. The action should have the correct action parts properly installed, should have the correct amount of friction, must be correctly regulated, and should be voiced to the pianist's liking. Only after all of these steps have been taken should any attempt be made to change the weighting of the keys by adding or removing lead weights.
Perhaps you have a vintage piano that has a number of problems with the keyboard, or perhaps the keyboard has been extensively damaged. In such a case, it is possible to replace the entire set of keys and keyframe. However this is an expensive operation costing several thousand dollars and it is usually only suitable for pianos that are undergoing complete restoration.