I have finished writing my book “Left-Brain Lutherie: Using Physics and Engineering Concepts for Building Guitar Family Instruments: An Introductory Guide to Their Practical Application”. Details can be found here.

The following article is from “The Colgate Scene” magazine, May 1997 who have kindly allowed me to reproduce it for my website. Colgate University, my undergraduate alma mater, may be reached at


by Rebecca Costello

David `Kawika’ Hurd ’64 says he can’t help being a researcher. After spending more than two decades in oceanography, he has carried over his scientific skills to a new career in the art of building a better ukulele.

Reflecting on how his mid-life switch in careers came to be, he looks back to his time at Colgate and describes himself as a thinker rather than a learner: “I didn’t get the best grades, but I was imaginative and determined.” He still is.

Hawaii bound

Hurd, who majored in chemistry, became an oceanographer in part on a whim. His senior year, he saw his first surf movie — Bruce Brown’s Surfing Hollow Days — in McGregory, he recalls. Then he saw an ad for the brand-new department of oceanography at the University of Hawaii in Honolulu. Still sniffling from his umpteenth bout with the flu and nasty colds, he thought, “There is a better life. Aloha to Chenango Valley.

“It was a zoo,” Hurd remembers of the budding oceanography program back in 1964. “There were only two faculty members, and only three-quarters of an assistantship. My friend got half and I got a quarter — about $1200 a year. Unthinkable. It was just enough for gas, laundry and surf wax.” So he also took a job as a short order cook, and soon after met his wife to be, Helen.

Hurd left grad school for a time to spend four years teaching high school science at The Kamehameha Schools in Honolulu, then finished his M.S. in 1969 and got his Ph.D. in 1972.

His dissertation research was on the geochemical cycle of silica. “I looked at silica more quantitatively than earlier researchers using surface and physical chemistry — how these skeletons of little plants and animals in the ocean dissolve and re-precipitate, the range of its properties and how it changed though time,” he explains.

For the next ten years Hurd worked, mostly under federal grants and contracts, in a varied career in oceanography: at the University of Hawaii, at Hokkaido University in Japan, and at the Woods Hole Oceanographic Institution. Then “the funding cuts in the Reagan years ended that stint,” he says. Hurd moved over to industry in 1981, as a research engineer for Shell Development Company in Houston, Texas. Shell Oil had just bought the Belridge oil field near Bakersfield, California, where the reservoir field was primarily diatomite, a rock composed of the same material Hurd had just spent a decade trying to understand: “I didn’t know much about geology or engineering,” he explains, “but I knew how to do original research, and that’s what Shell wanted.”

Making a change

After eight years, though, he wanted to get back into oceanography. “I was approaching 50, trying to figure out what I wanted to do,” he recounts. “It’s a time when you question — whatever career you’re in — whether you’re going to be successful, be happy doing it, and whether it’s time to make a change.”

Hurd knew he would have to play catch-up. Leaving Shell, he spent two years in charge of day-to-day operations at the Joint Global Ocean Flux Study of the National Science Foundation’s Oceanography Division until, he recalls, “it became apparent that other people in the general academic community thought I had been away for too long (to be part of the actual academic community rather than a science manager).” It was 1991.

“I had been making instruments for four or five years as a hobby,” he explains. “We looked at the market in Hawaii, and we came back. We bought a nice old house in Hilo, Helen’s hometown.”

The couple opened a shop on the first floor of their house. It was a fortunate time to enter the business. The ukulele was becoming more popular but there were few professional or amateur instrument makers on the island. “I could sell everything I made and support myself doing it,” Hurd says.

The business is called Ukuleles by Kawika, Inc. Kawika is the Hawaiian equivalent of Hurd’s Christian name, David. He also recently began making nylon string guitars; his wife Helen makes repairs on instruments brought in from the community.

Hurd builds his instruments without excessive inlay or ornamentation, instead preferring to enhance the qualities of highly figured or spalted koa wood. He’ll sometimes use redwood, Western red cedar and Douglas fir for the tops, but he primarily uses koa. “Koa is so inherently beautiful,” he glows, “that I prefer to emphasize what occurs naturally in terms of grain and color. And koa is endemic to Hawaii.” He usually makes ten ukuleles at a time — a two-month process.

Some might contend that building an instrument out of a non-uniform material like wood can’t be an exact science. Even an expert can randomly make a dud — or an extraordinary instrument — and won’t know why. Yet Hurd has found a way to make ukulele building as much science as craftsmanship, with consistent results. After several years of research and experimentation, he is proud to say that the sound quality of all of his ukuleles is very good.

A digital fingerprint

“Some are exceptional,” Hurd remarks, “for their sustain, clarity and projection. A scientific approach encourages reproducibility of those qualities.” Hurd uses a computer to measure the acoustic qualities of each instrument he builds by recording tap tones of the top and back. Tap tones contain the frequencies natural to the harmonic resonances of the wood. He compares these `digital fingerprints’ to those of optimal-sounding instruments stored in his database of sound files on the computer.

“I’ll take pieces of wood, saw them an eighth of an inch thick and bookmatch them to a standard thickness. Then I measure weight and dimensions and calculate density and stiffness using Chladni patterns and a frequency generator,” he explains. “Different woods have different stiffness coefficients, but I can back-calculate how the wood I’m using compares to my standard.”

Minutely adjusting to what the computer tells him about the sound quality, Hurd shaves portions of the brace woods using small finger planes. “When you’re getting close you can feel a wave pulsing through the instrument when it’s tapped in a certain place,” he explains. “That’s when I feel like a luthier.”

Hurd continues to experiment. “As you get better you find another step that lengthens and complicates the process,” he explains — like the resin-reinforced necks he now installs in all his tenor and baritone ukes for added strength and better tone.

Marketing is Hurd’s new challenge. “Now there are many more ukulele makers and more imported instruments. It’s much more aggressive,” he says. “We do make the nicest playing instruments, but I’m afraid we’re still a little bit too much of a well-kept secret.” But while he’s exploring new marketing approaches, something as simple as word of mouth can bring a windfall. “I have sold five or six instruments in one family,” he remarks. The shop is also represented in cyberspace with a comprehensive World Wide Web site (, complete with vivid descriptions of his building and finishing techniques and sound files you can download to hear recordings of his instruments.

The shop is continually evolving and Hurd says it will probably never be finished.

“You never have enough room,” he laments. “But at last the commute is pretty good.”

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