Plywood

Some Observations and a Report on the Use of Laminated Wood in Lutherie

by R.M. Mottola

Originally published in American Lutherie #73, 2003 and Big Red Book of American Lutherie Volume Seven, 2015



Considering that most stringed instruments are made in factories by large companies, and that the instruments at the low-priced end of these companies’ product lines are sold in great quantity, and that these low-priced instruments are frequently constructed of laminated wood (i.e., plywood), it is not at all unreasonable to assume that most of the instruments made are probably constructed from plywood. Further, as plywood is a physically robust material, it may be reasonable to conclude that the majority of the stringed instruments extant are made of plywood. For some reason, plywood is associated only with cheap instruments, although there are some exceptions. A cursory review of the lutherie literature reveals not too much in the way of scientific experimentation that would change that association, but it does provide a number of interesting anecdotes and observations that may indicate that plywood could be a far more useful material for high-end instruments than generally thought.

The very first issue of The Guild of American Luthiers Newsletter (Vol. 1 #1) contains a letter by R.E. Bruné describing the construction of classical guitar ribs made of rosewood/maple laminate, a construction which the author claims to increase volume. In his review of a harp kit in American Lutherie #69 (Big Red Book of American Lutherie Volume Six), John Calkin compared the tone of two dissimilar harps, one with a solid top and the other with one of plywood, and found the plywood one to sound “bolder and a bit louder.” An interesting observation can be found in the bible of flattop guitar making, Cumpiano and Natelson’s Guitarmaking: Tradition and Technology. They opine that lateral stiffness of a guitar top will greatly influence the tonal response of the instrument and state that superior lateral stiffness will allow the top to be worked thinner, thus reducing mass. Now, they’re not talking about plywood here per se. A top made of, say, three-ply spruce with the center ply oriented at 90° to the outside plies should be stiffer across the grain than a solid top of similar thickness. Kevin B. Reilly described small-bodied guitars he made using birch ply for the tops and backs in AL#61 (BRBAL6), and found these instruments to have considerable volume and sustain.