This is the material on restoration requested to be posted. Obviously every piano must be evaluated on an individual basis and this outline only reflects what I commonly expect. I didnt include other concerns and unusual problems that would of obscured this background information. The class its self went into more detail, such as spotting often overlooked problems, dealing with previous repairs and avoiding misdiagnosis. Of course these suggestions apply primarily to quality American grands. GRAND PIANO REPAIR AND RESTORATION OUTLINE John Hartman 1993 New Piano Less than one year old: Roughly reset hammer line and spring tension. Roll the jacks and touch up key level. Tighten up all the shank screws, check let off and touch up hammer spacing. Tighten screws and space repetitions. Fine set hammer line. Make sure that the trap work is functioning correctly with proper lost motion and stopping. Check string voicing and fine tune. Go over hammer voicing working primarily on or near the strike point with a sugar coater or a single needle. The object is to reduce the volume of notes that are either too loud, too harsh and/or too brilliant. Make each string in each unison have the same volume. Pianos from five to twenty years old: Remove action and clean strings as needed. Using a vacuum and compressed air clean plate, sound board and key bed. With the action on a bench remove the action frame from the keys. Remove all the keys and vacuum off the key frame. Polish the key pins as needed. Lubricate the key pins with "MacLube 1725". Replace the keys on the key frame and polish the capstans. With a brass brush clean the knuckles and support cushions. Work the brush in one direction parallel to the parts. Lube with "Dry-Lube". Repair action centers as needed. Travel and burn shanks. Reshape hammers. Starting with leveling the keys, proceed with all steps of a complete regulation and voicing. If there are problems with the dampers be prepared to repair, regulate and voice them. Twenty to forty years old: Restring piano only if pin block is sound with only a few lose pins and all the pins are 2/o. If not, replace pin block. One of the reasons for restringing is to re-establish proper down bearing. Remove plate and trim plate support dowels as needed. If you are replacing the pin block consider lowering the front bass corner to improve front bearing. Repair minor cracks in sound board. Refinish plate. Drill out original block with a "J" drill bit and restring with 4/o pins. Chip tune three times with string stretching and setting. Install new hammers and shanks. Clean and repair all original action parts including damper action and trapwork. Rebush damper guides and keys as needed. Clean, refelt and regulate dampers. Regulate, tune and voice. Over forty five years: Replace sound board and pin block. Repair and refinish case. Replate hardware as needed. Repair or replace key tops. Completely disassemble action and clean keys, key frame and action rails. Replace letoff button felt. Rebush keys and refelt key frame. Replace back check leather (or new back checks) and key end felt as needed. Refurbish or replace repetitions. Install new hammers and shanks. Clean and repair damper action.Refelt damper heads. Clean, refelt and releather trapwork. Tune, regulate and voice. Pianos built between 1855 and 1880: Don't expect these pianos to hold up to heavy use but if carefully restored they can be fine instruments. Restoring pianos from this period requires the application of more conservative techniques. Make no alteration to the action, soundboard or case to modernize. Clients that want these changes should be persuaded to own a modern piano. Do not replace action parts with new manufactured parts even if they are close in size and shape. Rather, repair existing parts extensively by making wooden patches and refelting and releathering. If some parts are not repairable, make duplicate parts from scratch. I consider it permissible to install new sound boards and pin blocks only if the replacements are exact duplicates in every way and only if repairing these parts is impractical. Restring with modern music wire and tuning pins. Tune to standard pitch if possible. Before 1855 Pianos of this vintage are of interest primarily to musicologists, collectors, and musicians specializing in performing on original instruments. Even when these pianos were new they needed constant service in order to keep them functioning. Tuning stability was practically non-existent on many makes. Keeping this in mind, these antique pianos should never be considered for regular use in the home. Still, many of these pianos are being pressed back into service for performance, recording and study. Considering that the goal of any restoration for these pianos is to bring the piano back into playable condition while maintaining it's original qualities, only the most conservative approach is permissible. Keys and other action parts are cleaned with an art gum eraser. Original action parts are repaired with materials that match as close as possible. For example, when replacing leather on hammers and other action parts, it must be the same thickness, species, and tannage. Duplicate replacement parts are permissible only in extreme cases. The soundboard is to be retained at all costs, capping the bridges and shimming if needed. In some cases the soundboard is removed for repair work. The pin block is replaced with an exact copy only if repairing and patching fail. In ether case the original tuning pins and music wire must be retained. The finish on the case is never stripped and refinished, rather repaired with appropriate materials. Originally pianos of this vintage where tuned some what lower than todays standard. In any case never tune these closer than a semitone flat from modern pitch.
This PTG archive page provided courtesy of Moy Piano Service, LLC