The bracing layout is in pencil, once the rosette is installed and soundhole cut
What a busy week! With 9 hours per day spent between lecture and shop time, we have our hands full with our building schedule. While we do have the benefit of jigs set up for certain tasks, such as sanding a radius into brace stock, otherwise we spend a bulk of our time learning how to carefully attach small pieces of wood together, then elegantly carving away much of the material we’ve just attached. What remains is the guitar.
The bracing of the top is a great part of the artistry of guitar making and design. You would think that the soundboards of a guitar would be made flat and strong, right? What isn’t apparent when looking at a fine guitar, is how it has been engineered to withstand the constant pressure of the strings, not to mention made to sound good when played.
Flat to the untrained eye, the top (front, usually light-colored spruce), top braces (the sculptural reinforcement glued to the underside of the top, mostly hidden from view), back, and back braces are a much more complex system than first meets the eye. Modern guitars are built “under tension”, meaning that the top and back plates (the major sources of sound from the instrument) are forced into a subtle arch during construction.
The plates are first sanded flat and fairly thin. Next, the sturdy spruce braces that are to be glued inside are given a radius usually between 15′ and 25′. When glued to the top and back, these braces induce arch into the thin plates. This creates a stronger and more resonant structure. It is also a fair amount of work.
One of the wonderful clamping tools we use in the shop is called the Go-Bar Deck. The deck consists of two plywood plates held about four feet apart; the assembly to to clamped faces upward, and flexible shafts are bowed between the part being glued and the upper plate. This allows one full access for glue cleanup, fine control over clamping pressure, and and inexpensive alternative to using deep-throat clamps. Best of all, it looks way cool.
Once the braces are attached with hot hide glue, they are profiled and scalloped prior to final voicing. This is a major contribution to the fine, nuanced sound of a hand-built guitar. For a first-timer, it is also laborious and time-consuming. The 1930’s Gibson design I’m using has 14 bracing components. Each has a purpose, and each must be precisely fitted and shaped for the best result.
Meanwhile, back I’m listening to old reggae favorites and having nightmares about my chisels not being sharp enough. In other news, I’ll be taking a trip down to visit friends in Viroqua, Wisconsin this coming weekend. While I’m down there, I’ll be participating in a wonderful radio show sunday evening. Styled after the great old-time radio barndance programs of the 1930s, the Driftless Radio Barndance is loving variety show played live in a gorgeous tobacco wharehouse-turned-bookstore in Viroqua. You can expect some fiddle music, some fine country harmonies, and plenty more. You can listen in live streaming around 7pm this Sunday February 3rd, 2013.
And what is possibly the most beautiful book store in the whole world: