Piano refinishing or cabinet restoration refers to the exterior non-mechanical part of a piano. Usually, wood finishing and wood repair is addressed. A large percentage of a piano’s value, to most owners, is aesthetic beauty. The shape and size of both a grand piano and an upright (vertical) piano holds a demanding presence in the décor of any home, stage, of studio.
For hundreds of years, since the first stringed keyboard instruments were built, aesthetics dictated construction of the piano’s exterior cabinet. Of course, musical design and engineering took precedence over appearance but most makers invested tremendous effort into making their products appealing to the eye. So much so that there are many instruments made today that look far better than they sound and play.
Piano finishes are either opaque or transparent. Pianos with colored finishes such as ebony or white generally will not have exquisite exterior veneers beneath the finish, as used in wood grain finishes where the grain will be visible. It is common to find poplar, maple, birch, or other closed grain woods used. These pianos generally are kept opaque when refinished.
Wood grain finishes use the highest quality wood veneers from all around the globe. Commonly, in our shop we work on North American and European pianos which use South American and African Mahogany, Black Walnut, English Walnut, Carpathian Elm, Cherry, Oak, Rosewood, Bubinga, and other hard woods with exotic appearance.
Two factors affecting the appearance of wood is coloration (staining) and milling. Different wood can be stained for saturation, hue, brightness and other values. Additionally, the angle at which the veneer is milled will affect the splay of grain, radically changing appearance. The time period of when the instrument was built will have bearing on these factors. This is important to note when embarking on cabinet restoration.
Piano Refinishing will involve removal of old finish, duplication of wood parts such as moldings, carvings, case parts, and splicing veneers. This page will exhibit our practices of the most common details of piano cabinet restoration.
The first step in piano refinishing is breaking down the cabinet into its smallest parts. The number of individual parts that make up a piano cabinet is surprisingly large. Each piano consists of thousands of square inches of surface space, making piano refinishing an extensive task requiring a fairly large quantity of materials.
A piano refinisher benefits from having a good understanding of piano construction. Each part needs to be removed, hardware needs to be removed and cataloged, and notes need to be taken of any damaged, altered, or missing parts. Once done the parts are ready for stripping.
Pictures show old finish being removed with a chemical stripper. Picture on right shows wood after stripping. Since 99.9% of pianos ever built are constructed with lumber core material (not solid wood) the exterior veneer cannot be sanded to remove finish. Lumber core is a high grade wood product consisting of core wood (generally poplar, ash, or basswood) and two layers of veneer: one cross banded perpendicular to grain of core wood and a second on the exterior surface. This is done on both sides of core wood to make up a 5 ply panel. It is the exterior veneers that will give the piano its wood distinction such as mahogany, walnut, etc. This does not mean that the entire piano is made of this wood. Solid lumber core construction is most stable, disallowing warping and expansion movement which will crack and damage finishes. Excessive sanding of veneer will damage the veneer by sanding through it, or changing its thickness and ability to absorb stain evenly.
After stripping the case wood is in the raw. Each part is carefully inspected for dents, starches, loose veneer, and damaged veneer. All repairs are made before beginning preparation for new finish. These pictures show the rim ready for inspections and veneer damage to the cheeks.
Damage veneer is removed and new pieces are cut from paper templates used to trace shape onto sheet of new veneer.
New veneer pieces are clamped and glue onto the piano. Veneer must be clamped with adequate pressure to assure a good bond (approx. 105 pound per square inch). Since the veneer is less than 1/32” thick and pervious care must be taken to apply the correct amount of glue so glue does not penetrate the veneer. This would cause uneven absorption of dye stain.
New veneer is trimmed and sanded. Proper sanding will allow seams to blend and stain to match evenly with the original veneers.
Damage such as the edge of this lid are repaired using matching solid wood. This allows for edge profiling and heavy sanding to blend piece in. Once stained the repair should be transparent.
A penetrating dye stain is applied according to color preference selected by client. A seal coat is then applied to seal stain and fill and level pores.
Multiple sealer coats are applied and sanded between applications.
Multiple top coat layers are applied with wet sanded between applications. The top coat is a high grade catalyzed material with different sheens. Shown here is a semi-gloss that will be rubbed out to a medium- luster sheen.
Final top coat is wet sanded with ultra-fine sand paper and prepared for final rubbing.
Rubbing and polishing compounds are used to bring finish to final desired sheen.
Case parts are prepared for assembly. All screw holes are reamed out and holes are dilled for new rubber cushions. This is a step that is often neglected by inexperienced finishers or craftsmen unfamiliar with pianos. It is very important to understand the assembly of a piano case at this point and to use the correct felts, leathers, and cushions.
Each piece of hardware, including every screw head, is polished. In cases where metal is damage or plating is worn through the hardware is replated with nickel or brass.
1920’s circa refinished piano is fully assembled with new fall board decal. We make every effort to assure the final product does not look “refinished”, rather like new.
Please remember that this, and all other technical information in this site, is not a DIY tutorail. Rather it is for reference and intended to inform our clients on our standards of practice. There are many critical steps involved with refinishing a piano that are not illustrated here.