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Finishing Lute Soundboards

Finishing Lute Soundboards

by Lawrence D. Brown

Originally published in Guild of American Luthiers Data Sheet #229, 1982 and Big Red Book of American Lutherie Volume One, 2000



There has been much discussion in early music journals recently about the materials used to finish lute soundboards. It would certainly be to our advantage if we knew exactly what was used on the soundboards of old instruments. Some people suggest that it is a moot point because no one is using exactly the same wood for soundboards that was used on old lutes. The old lute makers were almost certainly working under the same commercial pressures as any 20th-century workshop, and like us, used whatever high-quality timbers they could get ahold of. In addition, different luthiers probably used different materials and techniques to finish their soundboards.

It is well known that old lutes have very little or nothing at all on their soundboards. This would seem to be the most relevant point of all. Modern craftsmen have discovered that even one coat of varnish on a lute soundboard has a deleterious effect on the tone of the instrument.

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Finishing Lute Soundboards

by Lawrence D. Brown

Originally published in Guild of American Luthiers Data Sheet #229, 1982 and Big Red Book of American Lutherie Volume One, 2000



There has been much discussion in early music journals recently about the materials used to finish lute soundboards. It would certainly be to our advantage if we knew exactly what was used on the soundboards of old instruments. Some people suggest that it is a moot point because no one is using exactly the same wood for soundboards that was used on old lutes. The old lute makers were almost certainly working under the same commercial pressures as any 20th-century workshop, and like us, used whatever high-quality timbers they could get ahold of. In addition, different luthiers probably used different materials and techniques to finish their soundboards.

It is well known that old lutes have very little or nothing at all on their soundboards. This would seem to be the most relevant point of all. Modern craftsmen have discovered that even one coat of varnish on a lute soundboard has a deleterious effect on the tone of the instrument.

The main concern of a historical instrument maker is to produce instruments that are acoustically, mechanically, and aesthetically similar to the instruments produced by early makers. This does not, however, preclude the use of any and all modern finishing materials. Modern lute makers must also respond to commercial forces and the demands of their customers, as long as this can be done within historical parameters. Bare wood accumulates sweat and dirt at a rate that is intolerable to musicians who are used to having a protective varnish on their instruments.

Because I build a great many lutes each year, I have been able to experiment with a variety of protective coatings on lute soundboards. Although my main concern has always been acoustical, I cannot ignore cosmetic considerations since lute making is rapidly becoming a very competitive market. For this reason, I have tried and rejected egg white sealers because they turn green — especially where the soundboard comes in contact with skin. Sodium silicate (water glass) also turns green and must be tinted with an orange dye in a lacquer overcoat. Oil finishes penetrate the wood too deeply and remain soft. They also collect dirt and discolor badly.

What is needed is a finishing material that will adhere to the surface but not penetrate it very deeply, a material that will dry to a hard, durable surface resistant to mild solvents; and a material that will go on in an extremely thin layer, so as not to have an adverse effect on the tone of the instrument.

This is the most successful method that I have found so far. It requires the use of a compressor and a spray gun, lacquer sanding sealer, lacquer, and lacquer thinner. I use a touchup gun. It is smaller than a standard gun and holds about a pint of liquid. It also has a smaller spray pattern than a larger gun, which seems about right for spraying a lute-size instrument.

Mix 1 part lacquer sanding sealer with 1 part solvent. This makes an extremely thin solution that dries instantly when sprayed on the soundboard, preventing it from soaking into the wood. (If the spray gun is held too far from the soundboard, the solution will dry in the air and deposit a dusty film on the instrument.) Sand lightly with very fine paper or steel wool. This is followed by two coats of lacquer, also mixed 1/1 with solvent. This makes an extremely thin coating that seems to have no effect on the tone of the instrument, but provides a hard and reasonably durable surface. The lacquer sanding sealer not only seals the wood but makes an excellent bonding coat between the wood and the lacquer coat. The surface may be lightly smoothed with steel wool. The reduces the gloss to a uniformly dull finish.

I have tested the acoustical effects of this finishing technique by playing the instrument in the white and after being finished. I have also compared the tone of finished instruments to identical instruments that have not been finished.

It has been noted that old lute soundboards seem to be somewhat dark in color. This was probably due to the effect of ultraviolet light on the wood. Mask one-half of a newly cut and sanded soundboard with heavy paper and leave it around the shop for a month. It does not have to be in direct sunlight. Notice how dark the exposed side of the wood becomes after such a short time. I have noticed that different types of spruce seem to darken more quickly than others. I really doubt that early lute makers artificially darkened the soundboards of old lutes, since this would mean coating the wood with an additional substance when the tendency seemed to be to put as little as possible on the soundboard.

I regularly get a variety of Middle Eastern stringed instruments, including ouds, in my shop for repair. These instruments normally have bare, untreated soundboards. The older ones (20–60 years old) have turned quite dark and closely resemble the lute soundboards in old paintings. In most instances they are not just UV-light darkened but uniformly dirty. In any case, why should we be trying to build lutes that look 20–60 years old when they are brand new? I, for one, am content to wait a few years.

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Rosin Varnishes

Rosin Varnishes

by Louis DeGrazia

Originally published in Guild of American Luthiers Data Sheet #226, 1982 and Big Red Book of American Lutherie Volume One, 2000



Rosin varnishes are shunned by master violin makers because they are soft, “chippy,” and do not adhere well. Yet they are not so bad in these respects that they could not be used by an amateur or beginner on instruments with no pretension to outlast their maker. Pale rosin is a wonderful, natural, wood-derived resin that can be very easily made into a variety of beautiful and acoustically suitable varnishes both of the spirit and oil type. Its solubility in both alcohol and turpentine and its compatibility with oils and other resins make it a versatile ingredient that can help in combining normally incompatible substances to achieve special properties. Rosin varnishes have been around for centuries and in some respects they resemble those of the old Cremonese masters.

Pale rosin in powdered form can be obtained from pharmaceutical companies which use it in preparation of salves and ointments. This is the purest grade and is recommended for varnish making.

Rosin can be added to many varnishes to add body and to make them softer. Adding rosin to shellac makes a “woodcarver’s varnish” that can be prepared in just a few minutes, although it is best to let it stand overnight. This varnish brushes well, dries considerably slower than straight shellac, has good luster, and is much softer than shellac. To prepare, simply dissolve as much rosin as will go into solution in orange shellac and strain.

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Electronic Aiding of Stringed Instrument Sound

Comment on Electronic Aiding of Stringed Instrument Sound

by R.W. Burhans

Originally published in Guild of American Luthiers Data Sheet #10, 1975



Introduction

In perspective we should view modern sound reproduction as an “Electronic Art” which requires somewhat different types of skills than the “Mechanical Art” developed by the Luthier. The same type of careful attention to detail are required in both and there is no substitute for long hours at the workbench with a lot of reading of the literature published in periodicals like: Popular Electronics, Radio-Electronics, Rolling Stone, Guitar Player, Electronotes Newsletter, Journal of the Acoustical Society of America, Journal of the Audio Engineering Society, and even Scientific American. There is even a trade quarterly circulated to music shops, Musical Product News and Musical Electronics, which is a sales promotion and product announcement type with information on the myread of stuff on the current market. Still others are dB the sound studio engineers magazine, a magazine called Audio, and another DB, Down Beat.

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Bow Hair Jig

Bow Hair Jig

by Thomas Snyder

Originally published in American Lutherie #3, 1985 and Big Red Book of American Lutherie Volume One, 2000



As and apprentice luthier, I have come up with a better mousetrap for rehairing bows. The results with this method have been uniform hair tension, long-term retention, and reduction in rehairing time.

The jig was fabricated from pine and oak. I used oak on all blocks. Item 4 makes a great carving back for ferrule wedges. I average ten bows a month and this method and jig has cut my time in half and increased the quality.

On my sketch, items 2A, 2E, 2D, and 2F are the new additions to an old jig. I have made a few small changes. For the lack of a name, I will call this a “hair holder.” Item 2A swings aside to place hair over sponge rubber. The half of a 1/8" dowel holds the hair in place when the wing nuts are tightened.

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Making Lining Strips — One

Making Lining Strips — One

by Rolfe Gerhardt

Originally published as Guild of American Luthiers Data Sheet #71, 1978 and in Lutherie Woods and Steel String Guitars, 1997



I used to make lining strips one at a time, a long, tedious process. Then I visited Charlie Hoffmann in Minneapolis and was inspired to work out this gang-saw setup. The saws are 6" plywood saws, very small kerf, and are spaced on the radial arm shaft with 1/4" spacers. Three blades fit comfortably on my radial arm saw. The holder is a board with a guide strip and two hold-down springs. This holder is clamped to the radial arm saw table. I hold the strip I am sawing with my other hand.

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