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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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Intro to P.E.G.

Intro to P.E.G.

by H.E. Huttig

Originally published in Guild of American Luthiers Data Sheet #35, 1976



This is an abstract of an article written by Mr. H.L. Mitchell, retired Chief of the former Division of Wood Quality Research, Forest Products Laboratory, U.S. Dept. of Agriculture. Not all material contained may be useful to luthiers. I leave it to the individuals to choose such things as they may wish to try and to apply to instrument building.


Wood is an exceedingly complex and variable material. You will know that wood shrinks and swells with changes in atmospheric moisture. This plus problems of checking, splitting, warp, and broken glue joints are all too familiar to you. Treatment with PEG (Polyethylene glycol–1000) greatly improves the dimensional stability of wood and eliminates many of the problems.

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Glass Jars for Spray Guns

Glass Jars for Spray Guns

by Tim Olsen

Originally published in Guild of American Luthiers Data Sheet #91, 1978



Commercial spray guns, such as the DeVilbiss type MBC, typically use aluminum cans to hold the juice. Aluminum cans are lightweight and unbreakable. They are also expensive and inconvenient, in that they must be labeled; the contents can not be viewed without uncorking the cans.

By substituting glass jars for the aluminum cans, many advantages can be realized:

Jars are cheap.

Jars are clear, allowing one to observe the contents instantly, and to check for sediments, precipitates, jungjills, farfles, and other forms of grungus.

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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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