From the Summer 2017 issue of Classical Guitar | BY BLAIR JACKSON

People do not usually associate classical- and flamenco-guitar lutherie with the sun-kissed islands of Hawaii, 8,000 miles from the birthplace of the Spanish guitar. Koa wood ukuleles, yes. Finely crafted concert instruments ready to tackle Tárrega or Paco? Not so much. But for nearly two decades, John A. Decker Jr. has been handcrafting instruments under the guitarmasterworks name out of his home shop in Wailuku, Maui, selling mostly to Hawaii residents who play classical and/or flamenco, but also occasionally shipping his custom guitars far beyond the Pacific.

What makes Decker’s story even more intriguing is that this master wood-carver made his name developing RainSong acoustic guitars, famous for their durable, carbon-fiber (i.e. non-wood) construction. “I retired from day-to-day operations with RainSong in 1998,” he says by phone from Maui, “and now I make classical wooden guitars as a sort of low-level occupation. I don’t make many—just a few a year, out of the usual exotic woods. But it’s ironic that I own a company that makes, give or take, a thousand guitars each year—almost all steel-string; we might make half a dozen or a dozen a year for nylon-strings—and they have no wood in them whatsoever.” His own classical models do, however, have carbon-fiber rods to reinforce the neck: “Particularly if one is using Spanish cedar for necks, which is traditional for classical guitars, over time the necks tend to ‘sag’ under string tension, and the carbon-fiber helps to prevent this. Otherwise, except a layer of Nomex in the [double-top] soundboard, everything else is wood.”

John a Decker Jr guitar process

Decker’s three-piece top leaves only the exterior layer of spruce contacting the sides, which he claims makes the “soundboard/sideconnection as flexible as possible.”

Decker’s background was not in music. As he put it in the biographical sketch on his website (, “I was trained as an aeronautical engineer [at M.I.T.] and a physicist [PhD from Cambridge U.], and spent most of my career as a technical manager, primarily in the semiconductor and aerospace industries.” Those experiences have greatly informed his guitar-making through the years—interviewing Decker about guitars would have been much easier if I’d taken physics and chemistry in high school. But I didn’t, so some of what he said frankly sailed over my head.

He first went to Hawaii for a project in 1971, “and I didn’t like it,” he said. “I don’t like big cities, and Honolulu is a big city.” When, a decade later, he was recruited to run the Air Force’s optical observatory on Maui (because of his groundbreaking work with computer-controlled optical instruments), he was reticent: “I had no intention of moving to Hawaii,” he notes. But he took the job and quickly learned that Maui was quite a different place than crowded Honolulu, and he was also very impressed with the observatory, which at the time was the world’s best ground-based optical facility, he says.

“Once I got out here,” he continues, “I got talked into learning enough guitar to lead the singing in our church group. I took [classical guitar] lessons—I never got to be good—and bought a guitar, but the guitar kept coming apart on me,” thanks to the notorious Hawaiian heat and humidity. This got him thinking about making a guitar that could stand up better to that sort of climate, and then the physicist (and chemist) in him took over. The notion of possibly fashioning a guitar out of carbon-
fiber or other sturdy materials that aerospace engineers had used on satellites and spacecraft intrigued him, because “I used to run a little department that made optical equipment for spacecraft—rockets and satellites—and vibrations were always a hazard for those. It turned out that the equations for the vibrations in a guitar soundboard are essentially the same as the equations for some funny acoustic waves in the sun that were the subject of my doctoral dissertation.

“In the course of all this, I recruited a classical-guitar maker, Lorenzo Pimentel in Albuquerque, New Mexico. His sons Rick and Roberto are still running the company. [See CG Summer 2015 for more on Pimentel & Sons.] He was incredibly helpful and basically said, ‘You can’t just be a scientist and a businessman off on the side.’ If you’re going to make guitars that sound good, you have to really know how to make a wooden guitar’ with, as he put it, ‘sawdust under your fingernails and lacquer in your hair.’ So I first built wood prototypes, which we then converted to carbon fiber [actually a carbon fiber-epoxy resin matrix—graphite]. And in the process of doing that, which took quite a long time, I became really intrigued with the craftsmanship involved, and I also learned a lot about wood. If you’re going to imitate a wood guitar, you’ve got to know what its properties are. A French lab has done an exhaustive study on the properties of tone woods—density, stiffness, and other characteristics—so I used that.”

Heel cap on a high-figure bubinga guitar

Decker says it took about ten years “to get a system that was manufacturable,” but once it was rolling, RainSong’s steel-string composite acoustic guitars took off. Unfortunately, the company’s attempts to also sell graphite classical models did not succeed: “It’s a very tough market to crack,” he acknowledges. “I remember taking one of the RainSong prototypes into one of the really nice classical-guitar shops in San Francisco and I got thrown out as if I had the Ebola virus! There are probably 25 or 30 classical RainSongs, and maybe a dozen flamenco RainSongs, floating around the universe somewhere, but we haven’t made one since ’96 or ’97.”

All along, Decker had been immersing himself in the history and physics of guitar building (read “Guitar Acoustics 101” on his website… if you dare!), he joined the Guild of American Luthiers and its spin-off, the Association of Stringed Instrument Artisans (ASIA), and “I read everything I could find.” However, typical of this iconoclast, when he ventured into making his own wooden classical and flamenco guitars following his semi-retirement from RainSong in 1998 (the company moved from Maui to the state of Washington three years later), he did not adopt conventional soundboard bracing á la Torres, or the more modern (Michael) Kasha bracing in Richard Schneider’s instruments. Instead, he opted for the proprietary brace-less “double-top” design he had developed for RainSong—and then licensed back from the company. Again, this went back to his aerospace engineering background, specifically to the concept of “aeroelasticity.”

“What you want for a guitar soundboard is almost exactly what you want for an airplane wing—you want it be as light at as possible, as stiff as possible, and have no funny resonances. On a guitar soundboard this meant you build a three-dimensional version of an I-beam, with the top thinner than normal, then a spacer—on RainSong we use foam, on wooden guitars we use Nomex—and then a backing plate. It’s sort of a double-soundboard, except we discovered very quickly that if those two plates were the same thickness, it was overbuilt like mad. So, I use a regular soundboard—spruce or whatever, typically a half to a third the thickness you use for a plain solid soundboard—backed up with about a 1/8-inch layer of Nomex, and then a backing plate, as I call it, as thin as I can get it; typically 1/3-millimeter thick. The other thing I incorporate is, unlike just about everybody else who uses a ‘double-top approach,’ I don’t carry the Nomex and the backing plate clear to the sides of the guitar. That is another old idea from aerospace: You don’t want the vibrations of the soundboard to go into the body of the guitar. It drains energy you really want to project out to the audience. I’ve found that we get a nice response across from bass to treble and it’s loud. It shows up particularly in the flamenco. I make really thin-body flamencos, and they’re almost as loud as my full-size classicals.”

If you scroll through the “Gallery” on the guitarmasterworks site (he says he chose the name and writes it as one long word to evoke a “German” vibe), you’ll find many beautiful instruments made from combinations of exotic and more typical woods, including spruce, koa, bubinga, redwood, Claro walnut, “10,000-year-old pepperwood,” mahogany, pre-CITES Brazilian rosewood, Cambodian rosewood, Malaysian blackwood, ebony, Caucasian cypress; the list goes on. I ask him if he can hear much difference in the various woods he employs.

“You can clearly hear the differences between the soundboard materials. I’m a real fan of redwood, for instance. It has a lovely, warm tone as a soundboard material, but I make sure that people understand that it is very fragile. It’s very soft. You don’t want it in a flamenco guitar. If someone has well-developed nails for strumming, you want to stay away from redwood. One of the things I enjoy about making wooden guitars is talking to a customer—what kind of tone do you want? And they’ll play the guitars I have, and they might like the spruce best. A lot of people do. Lorenzo Pimentel taught me how to ‘listen’ to a piece of wood by tapping it a certain way, to figure out if you’d want to use it on a guitar.”

Is the obsession with rosewood or flame maple back and sides driven more by aesthetics than tone? “From where I’m sitting, very much so. But that’s fine. I love beautiful woods. I just built a guitar out of Madagascar rosewood. I’ve got a filing cabinet full of back and side sets, and the client came by and looked through it and said, ‘I like that.’ Then we went through a cabinet of guitar tops, and he chose a Sitka spruce top. Then you go worry about fret boards and all that. I use mesquite as a fretboard material fairly often. It’s sort of a reddish light brown and it goes very well with a redwood top. My wife is from Texas and I happened to stumble on a source for mesquite from this place in the middle of nowhere. It’s very, very hard, perfect for fretboards.”

About half of the guitars Decker makes these days are custom commissions, the other half “dealer’s choice,” so to speak. “I usually have two or three in process at any given time,” he explains, “and if I haven’t got an order to keep me busy, I crawl through the woods I’ve got and pick something I like and make it.”

That sounds about right for what is truly, above all, a labor of love.