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A Method for the Design of the Guitar Body Outline

A Method for the Design of the Guitar Body Outline

by R.M. Mottola

Originally published in American Lutherie #97, 2009

See also,
Parametric Models of Guitar Cutaways by R.M. Mottola
A Method For the Design Of the Guitar Body Outline Part 3: Compound Radius Curves by R.M. Mottola



One of the most tedious and time consuming aspects of designing a new guitar for me is the process of designing the body outline. The body outlines of my early instruments were the results of many hours of labor, usually over the course of many weeks. This process was so time consuming that I would often forgo it entirely, opting to reuse an existing body outline as is, or scaling up a guitar outline for use in an acoustic bass guitar. But over the years I’ve settled into a method for guitar body outline design which is far less tedious and consumes far less time than did my original efforts. This method involves the use of a standard model of the guitar outline. Use of this standard model helps to make the process of developing an outline more standard as well, and this in turn has resulted in the development of techniques which save time and frustration.

In this article I will be outlining the model and discussing some common guitar body types in the context of this model. In talking about the design method which makes use of the model, I’ll try to touch on some of the generic qualities of guitar body outlines and how they can be quantified in terms of the model. Finally, some of the tools and techniques of the method will be detailed. Please note that what I am discussing here is only the mechanical aspects of a body design. Issues of acoustics or ergonomics are not covered. Also note that this method works equally well with either pencil and paper or CAD drawing tools, although there are some differences in how these tools are used.

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Potassium Dichromate, Oxalic Acid, and Carnauba Wax

Potassium Dichromate, Oxalic Acid, and Carnauba Wax

by Jeffrey R. Elliott

Originally published in Guild of American Luthiers Data Sheet #52, and #55, 1977 and Big Red Book of American Lutherie, Volume One, 2000



Potassium dichromate. European luthiers commonly use potassium dichromate to give that nice, brown “aged” look to lighter, newer woods. It can be used by itself or mixed with aniline dyes for additional color tints. Primarily it has been used to darken the interiors of violin-family instruments, although I know of many who have used it on the exterior to darken spruce and maple. I have used it both inside and out to create a “naturally aged” looking wood on guitars.

Potassium dichromate is a chemical activated by light from the sun, sunlamp, or infrared lamp, but direct, natural, full-spectrum sunlight is best. Beware: Indirect light will not activate it, and the solution will tend to color the wood a murky green. The solution is rather weak — two tablespoons to one gallon of water. It can be applied by brushing or by wiping it on with a cloth (wear gloves). Although I have never tried it, I imagine a spray method would work as well. Whichever method is used, a light, even coat is recommended.

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Curved Panel Templates

Curved Panel Templates

by Reagan Cole

Originally published in Guild of American Luthiers Data Sheet #80, 1978



Many instrument makers prefer to build guitars, mandolins and the like with pronounced curvature to the back panel(s). The most common method of fabricating a “vaulted” back is to work from a solid plug mold which must be carved and shaped to very exacting standards to produce acceptable results. The plug mold is in fact the best answer when one is building a number of identical instruments. The drafting technique I shall describe is a workable alternative for “one-off” projects or as an aid in visualizing three dimensional forms.

Begin by making a full scale orthographic drawing of the intended form. This will show the back and side views, but it is not directly useful in determining the dimensions of thin wood (or other material) to be used in the construction.

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This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page.

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