Posted on August 15, 2023March 5, 2024 by Dale Phillips Questions: Gluing in India Questions: Gluing in India by Dale Zimmerman Originally published in American Lutherie #103, 2010 George Mathai from Kerala, India asks: My friend is a luthier based in the southern state of India, Kerala. For gluing the various parts and braces for his guitars and violins he uses Franklin Titebond glue and Behlen ground hide glue. However, in one of his custom-made flamenco guitars, a rattling sound brought the guitar back to the shop. One of the right fan braces had come off a bit and this was causing the rattling. For that guitar he had used the hide glue to glue the braces on. Kerala is well within the humid equatorial tropics and perhaps the humidity affected the gluing. What is the best glue that can be used to withstand high humidity? Dale Zimmerman from Franklin International in Columbus, Ohio responds: Hide glues such as our ready-to-use Titebond Liquid Hide Glue and most hot-pot hide glues are, and remain, quite sensitive to moisture. That affinity for moisture means that they tend to absorb water when exposed to high humidity or damp conditions, and that increase in moisture causes them to swell and weaken. Bonds that are not subject to stress may show little effect, as the glue loses that moisture and regains its strength as it returns to its original dry state. Where the bond is under stress, however, that stress is likely to cause some opening of the joint while the glue is softened. Ultimately then, the amount of change in a bond over time will be influenced by the concentration and duration of the moisture to which it is exposed and the stress, both inherent in the bond and that created as the wood involved changes in dimension in response to those changes in moisture content. That means that hide glues are generally considered a poor choice for bonds that are likely to be exposed to particularly humid conditions, especially those that are expected to be under meaningful stress. For such situations, yellow glues, which show little effect from dampness or elevated humidity are a decidedly better choice. ◆
Posted on August 4, 2023February 29, 2024 by Dale Phillips The Case for Using Natural Dyes The Case for Using Natural Dyes by Nicholas Von Robison Originally published in Guild of American Luthiers Quarterly Volume 11, #1, 1983 and Big Red Book of American Lutherie, Volume One, 2000 Luthiers do not need to color their raw materials as much as other woodworkers. We use fine woods that can stand on their own merit without any help from the dye pot. But now and then we do find a need for dyes: for example, for rosettes, bindings, taking grey streaks from ebony, enhancing the color cast of wood, and tinting finishes. In 1856 young William Henry Perkin was trying to synthesize quinine but instead wound up with a black tarry mess. This was mauveine, the first of the coal-tar derived dyes. By 1900 the aniline dyes (coal-tar derived) had virtually replaced all other dye materials. Up to this point, dyeing was done with naturally occurring materials and was more of an art than a science. With aniline dyes results were predictable, repeatable, stable, nonfading, and a heck of a lot simpler. There was bound to be a reaction, of course. The art of natural dyeing is returning to the amateur weavers and textile artists; I doubt if woodworkers will be far behind. 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 April 22, 2023March 5, 2024 by Dale Phillips Questions: Martin Finish Questions: Martin finish by Walter Carter Originally published in American Lutherie #104, 2010 Kerry Char from Portland, Oregon asks: Exactly what kind of finish were Gibson and Martin using before they switched to nitrocellulose lacquer? How was it applied, and when was the switch. I’m thinking that it was oil varnish similar to violin varnish, because it is resistant to acetone. But if that’s the case, how did Gibson do some of their sunbursts? I know that the earlier ones were rubbed, but later ones from the ’20s and ’30s look sprayed. Walter Carter from Nashville, Tennessee replies: Neither Gibson nor Martin made an across-the-line change from varnish to lacquer. Richard Johnston and Dick Boak note in their recent book, Martin Guitars: A Technical Reference, that Martin finishes were French polish (shellac) until 1918, when they began experimenting with different combinations of varnish and lacquer. Martin first used nitrocellulose lacquer in 1926, and by 1929 it was the standard finish on most Martin guitars. For Gibsons, Stephen Gilchrist offers this information: 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 April 22, 2023March 5, 2024 by Dale Phillips Questions: Nut Width Questions: Nut Width by Bob Pittman Originally published in American Lutherie #102, 2010 Rand Nooteboom from Haiku, Hawaii asks: Nut width varies from one instrument to the next and so does placement of the outside strings. What is the most reliable method of evenly spacing the remaining strings? Not just marking placement, but also accurately cutting the slots. Bob Pittman from Brookline, Massachusetts responds: For marking the spacing, I use the Stew Mac string spacing ruler (www.stewmac.com/shop/Tools/Measuring_tools/String_Spacing_Rule.html) and a .7MM pencil. The pencil is very fine and fits in the spacing ruler slots. The ruler does proportional spacing and I’ve never had a single customer complaint. I start with a nut cut square on all sides and sanded to 400 grit. I cut it to width and fit it into the nut slot. The outside strings are marked, then the nut is put in my nut vise, a Parrot vise with panels cut to 45° on the top edges so I can get at the nut. I mark the remaining slots with the string-spacing ruler and the pencil. With a 3" machinist’s square, I butt the edge up to the back of the nut next to a string mark. I use an X-acto saw and mark the top of the nut on top of the string line. (I think a Japanese-style saw would be perfect for this since it cuts on the back stroke, but I haven’t gotten around to buying one small enough.) I make sure the saw is perpendicular to the nut and flush against the square. With very light pressure, the slots are cut about 1mm deep. I put the nut back in the guitar, and nut files are used to finish off the slots. After that, I remove the nut, shape it on my sander, polish it with Micro-mesh up to 12,000, put it back on the guitar, and the guitar is ready to string up. ◆
Posted on April 22, 2023March 5, 2024 by Dale Phillips It Worked for Me: Low Cost Emergency Lathe It Worked for Me: Low Cost Emergency Lathe by Gerhart Schmeltekopf Originally published in American Lutherie #29, 1992 and Big Red Book of American Lutherie Volume Three, 2004 Most luthiers probably don’t have wood lathes, so I submit this low-cost, emergency lathe setup for the times you might want to make a music stand, washtub bass, or baseball bat for the local luthiers’ picnic. I bought commercial turnings to make a student harpsichord stand. They were “sanded and ready to finish,” so I knew that they would need to be sanded before finishing. They are too long for my lathe, so I rigged this temporary reciprocating or “pole” lathe to spin them and sand them. 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.
