Posted on August 1, 2022May 20, 2025 by Dale Phillips Spray Gun Agitator Spray Gun Agitator by Jimmie Van Originally published in Guild of American Luthiers Data Sheet #91, 1978 A new product that I found to be most helpful when spraying a finish or other things that had to be in complete suspension to assure uniform coverage, is a agitator siphon cup assemble sold by N.A.P.A. auto part stores. This cup will work on most major brand guns. The 1 quart cup provides constant agitation from air right off of the same line that your gun works off of, no extra line is needed. You can control the mixing speeds of the agitator, and does not require an extra cleaning. The part number you need to ask for is model 70-707. This may be of big help to those of you who do a lot of finishing work. ◆
Posted on August 1, 2022May 20, 2025 by Dale Phillips 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. Become A Member to Continue Reading This Article 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. If you are already a member, login for access or contact us to setup your account.
Posted on August 1, 2022May 23, 2025 by Dale Phillips Questions: Tru-Oil Finishes Questions: Tru-Oil Finishes by Jeff Jewitt Originally published in American Lutherie #90, 2007 ■ Eric Nicholson of Northern Ireland asks: Woodworker magazine published an article on Stewart Adamson’s work regarding Tru-Oil finishes. His method involved a considerable amount of work with Micro-mesh during the process. I tried his method on my own guitars, both classical and steel string, with very satisfying results. Tru-Oil gives an attractive semigloss finish on all woods, but Adamson also goes on to say that for those that like a gloss finish, a gloss tung oil is now available only in the USA. Does anyone know of this gloss tung oil and where it is available in the States, or if it is now available in the UK? Jeff Jewett of Homestead Finishing in Cleveland Ohio responds: Tru-Oil is not pure tung oil. It’s a mixture of linseed oil, mineral spirits, and, according to the manufacturer, “modified oil.” It’s arguable that no tung oil is even used in this stuff. When finish chemists talk about “modified oil” as an ingredient they typically mean either chemical modification or heat modification. Chemically modifying a drying oil involves reacting it with chemicals and heat to form what are known as alkyds, which are used in varnish manufacture. Heat-treated oils basically jump start the drying/curing process. Pure heat-treated oils are used all the time in making finishes, but they rarely show up as “finishes.” The only pure heat-treated linseed oil I know of is Tried and True “Varnish Oil.” Pure heat-treated tung oil is sold in this country under the Sutherland Welles brand (www.sutherlandwelles.com). So I would be tempted to say that Tru-Oil is a mix of linseed oil and some sort of modified linseed or tung oil. Because it has a high oil content, it is not possible to produce a very glossy finish. High oil (also known as long oil) products tend to form microscopic wrinkles at the surface as they cure. There is one way to heat-modify pure tung oil so that it will form a glossy film. This involves careful and controlled heating of the oil to about 450°F. Very few people can cook tung oil properly nowadays, but you can buy it under the Sutherland Welles brand “Original Formula High Lustre.” I don’t know if they will ship overseas. It’s not an easy finish to do, and I’m not sure that it will match the gloss of a French polish, but at least you know it is real tung oil, along with solvent and some driers.
Posted on August 11, 2021May 21, 2025 by Dale Phillips Violin Varnish and Sealers Violin Varnish and Sealers by Graham Caldersmith Originally published as Guild of American Luthiers Data Sheet #276, 1984, and Big Red Book of American Luthierie Volume One, 2000 Probably more unsubstantiated speculation has been written about violin varnish, its effects on the instrument, and the quest for the “lost” Cremonese recipe than about any other of the subtleties of the violin and its behavior. It is true that those who have examined enough violins to appreciate the variety of varnishing systems employed by different makers in different ages cannot but admire the clear golden-brown varnish sometimes grading to a deep red that characterizes 17th–18th century Cremonese instruments. It is also true that varnish preparation and application techniques changed to more durable and convenient ones towards the end of the 18th century when faster drying oil and spirit varnishes were developed to meet the needs of the growing furniture trade, arguably at the expense of transparency and lucidity. So while bearing in mind that the early Cremonese varnishes were not unique to the violin trade, since they appear on fine furniture and wooden ornaments of the same period, we may reasonably inquire as to how important the varnishing techniques used by the Cremonese Masters were to the excellence of the violins they produced. Were the advantages of Cremonese varnishing merely passive, in that they preserved good violins into sublime maturity, or were they also active, conditioning the wood for optimal acoustical behavior? Become A Member to Continue Reading This Article 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. If you are already a member, login for access or contact us to setup your account.
Posted on August 11, 2021May 21, 2025 by Dale Phillips Tinting Lacquer Marks Inlays Tinting Lacquer Marks Inlays by Michael Dresdner Originally published as Guild of American Luthiers Data Sheet #280, 1984 and Lutherie Wood and Steel String Guitars, 1998 When I have very intricate inlays and I don’t want to scribe the fingerboard, I take all the inlays and spray their backs with a rubber-type spray adhesive like photo mount. Then I place them on the fingerboard where I want them and spray it lightly with lacquer toner in a contrasting color. For instance, if the fingerboard is rosewood, I’ll spray it with bright yellow. I then pull up the inlays leaving the bright yellow lacquer and a brown spot in the shape of each inlay. It’s a great fast trick. The whole fingerboard can be done at once without any scribing. Become A Member to Continue Reading This Article 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. If you are already a member, login for access or contact us to setup your account.
