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> What is restoration?
> Casework
> Keyboard
> Cast iron plate
> Soundboard
> Bridge
> Action
> Pinblock
> Restringning
“Repair, Reconditioning and Rebuilding”
by Larry Fine.
THREE terms are often used when discussing restoration work on pianos: repair, reconditioning, and rebuilding. There are no precise definitions of these terms, and any particular job may contain elements of more than one of them. It’s therefore vital, when having work done on your piano or when buying a piano that has been worked on, that you find out exactly what jobs have been, or will be, carried out. “This piano has been reconditioned” or “I’ll rebuild this piano” are not sufficient answers. One person’s rebuilding may be another’s reconditioning.
Generally speaking, a REPAIR job involves fixing isolated broken parts, such as a broken hammer, a missing string, or an improperly working pedal. That is, it does not necessarily involve upgrading the condition of the instrument as a whole, but attends only to specific broken parts.
RECONDITIONING always involves a general upgrading of the whole piano, but with as little actual replacement of parts as possible. For instance, the reconditioning of an old upright piano might include resurfacing the hammers (instead of replacing them) and twisting the bass strings to improve their tone (instead of replacing them), as well as cleaning the whole instrument and regulating the action. If parts are broken or missing, of course, they must also be repaired or replaced, so this particular reconditioning job might also include replacing a set of bridle straps and other relatively minor parts, if needed. Rebuilding is the most complete of the three levels of restoration.
REBUILDING involves restringing the piano and usually, replacing the pinblock in a grand piano and repairing or replacing the soundboard. In the action, rebuilding would include replacing the hammer heads, damper felts, and key bushings, and possibly replacing or completely overhauling other sets of parts as well. Refinishing the piano case may also be done as part of a rebuilding job. Ideally, rebuilding means putting the piano into “factory-new” condition. In practice, however, it may involve much less, depending on the needs and the value of the particular instrument, the amount of money available, and the scrupulousness of the rebuilder. The bottom line is the restringing. If a piano has not been restrung, it really cannot qualify as a rebuilt instrument. Indeed, many technicians would assert that a piano has been rebuilt only if the pinblock has been replaced.
Due to the varied and sometimes unwarranted use of the word rebuilding, some rebuilders have come up with a new term -- remanufacturing -- to indicate the most complete restoration job possible, with special emphasis on the fact that the soundboard has been replaced, which may not be included in a regular rebuilding job. In my opinion, this new word only confuses the issue and, in time, it too will become tarnished. There is no substitute for requesting an itemization of the work performed.
To start the piano rebuilding process, first its essential measurements are taken and the case disassembled. All the metal parts and the mechanism of the piano are removed from the case, which makes the piano strings accessible. The strings are surveyed and removed.
After removing the strings, the massive cast-iron plate is dismounted. The soundboard and pinblock become visible. After removing the soundboard and pinblock, it is possible to dismount the case completely in order to start renovation.
Renovation works involve cleaning case details (sanding, removing old lacquer or paint), gluing, fitting new veneer at all damaged areas, lacquering and/or painting the case.
Keyboard cleaning - the keyboard is completely refitted. The keyboard is re-covered with synthetic material or the ivories will be carefully refurbished, i.e. ground, bleached and polished. New bone or ivory covers can be fitted at extra charge. Alternately, a completely new keyboard with a choice of key covers (plexi material, bone, ivory or Tharan) can be assembled and installed.
Common damage to the keyboard:
1. covering materials wear out or become deformed,
2. felt details wear out.
In the first case it is necessary to restore or replace the covering material, returning the keys to their right form and beautiful appearance. In the other case, the keyboard has some functional problem, e.g. a problem with alignment: waving, uneven height, inappropriate action (too deep, too low, unevenness, lateral movement). Removing such faults is the prerequisite to putting the entire piano mechanism in working order.
Unlike a guitar or violin, the strings of a piano are under 20 tons of tension and the main function of the cast iron frame is to withstand this tension. To renovate the cast-iron plate, it is cleaned, rebuilt (cast-iron welded, if necessary) and coated with bronze or golden powder lacquer.
A part of the great tension is transferred to the soundboard which is very sensitive to changes in temperature and relative humidity. These destructive influences can cause swelling, cracking or bending of the soundboard. The best material for a soundboard is spruce, the advantages of which are its hardiness and flexibility. Spruce is distinguishable by the structure of its long straight fibres, owing to which it is likely to split. Minor cracks need not be a problem but can become a risk if they are accompanied by damage to glued joints. Restoration of the soundboard consists of removing such defects and replacing the old resonance lacquer.
The bridge is the long curved strip of wood that contains all of the small pins. The bridge holds the strings in their proper position and at the right tension. Bridges that are broken or loose or have cracks running along the pin lines are a very serious problem. Evidences of inferior bridges are weak, "muddy" or poor tone quality, inability to bring a string to a clear pitch, and, in some cases, buzzing and rattling sounds. Bridges are replaced in the most severe cases. In most situations it is only necessary to remove the bridge pins, fill the cracks with rock-solid epoxy cement, and then replace the pins. When done as a complete restoration these repairs are performed with the plate removed.
The mechanism of the piano is an admirable engineering achievement. Its most complicated component is the figure which is designed to intermediate strong touches of the player’s fingers for years, but it can do it well only as long as it is kept in good working order and in the proper relation to each other. There are thousands of moving parts in the mechanism of the piano which wear out in the course of time. The older the piano is, the more likely the mechanism is so worn out that most of it has to be replaced.
In the course of restoring the mechanism, one or more of the working processes set out below are carried out:
• replacing covering felts,
• installing coverings,
• regulating contra-mechanism,
• replacing keyboard padding,
• aligning the keyboard and putting it in working order, replacing hammers.
Restoration or replacement of the mechanism is always followed by a calibration process in the course of which an experienced piano technician makes the thousands of parts of this complicated system work in harmony with each other.
The pinblock is made of glue-laminated wood and is located under the cast-iron plate. Tuning pins – screws made of steel - are fixed in the pinblock. The piano string is attached to the upper part. Turning the pins puts strain on strings and thus changes the intonation. Since the majority of the approximately 20 tons of tension is placed on the pinblock, inevitably the entire block must be replaced after 60-70 years. In the meantime it is still possible to make do with less money and put the pinblock into a condition where the piano can be tuned and will stay in tune. Some well-known piano manufacturers use beech and bubinga wood for making pinblocks. Veneer blocks made of Canadian maple are also used.
Restringing is needed for replacing broken strings or all of them. More often, in case of a full rebuild, all of the strings are replaced as due to the brittleness of the old string material, sound quality suffers and old string wires are in continuous danger of breaking. If all the strings are replaced, the coverings and old strings have to be dismounted, surveyed, stringing paddings replaced, agraffes and brass stringing details polished, and finally new steel and bass strings installed.
