Rural Missouri Magazine
Building on
a Moon Beam

Poplar Bluff luthier's mandolins shine
in a universe of imitators

by Bob McEowen

Glenn Robertson taps the edge of a mandolin body with a bass drum hammer as he tunes the top. The soundboard of a mandolin must be carefully carved to properly transmit sound. The Poplar Bluff luthier builds 10 to 12 mandolins each year.

Glenn Robertson holds the partially constructed body of a musical instrument to his ear and gently thumps it with the felt hammer of a bass drum. He listens intently to the wood resonate as he watches a sophisticated display on his workbench. The device, a stroboscopic tuner, shows him the exact pitch of the vibrations emanating from his mandolin soundboard.

After determining which areas of the body are vibrating freely and which are not, he lays the project on the bench and carefully trims the instrument’s internal bracing with a small plane. The procedure is repeated until Glenn is satisfied. When he’s finished, the gracefully arched soundboard will resonate like a speaker.

“You have to convince it that it’s a mandolin,” Glenn says. “Sometimes, it thinks it’s still a tree.”

Glenn builds mandolins in a small shop near Poplar Bluff. He is also building a reputation for stunning instruments that recall proven designs while setting new standards for sound quality and ease of play.

Glenn’s F-style mandolins are closely modeled after designs originated by the Gibson company, he incorporates subtle differences that make the instruments favored by players.

“We don’t have a traditional mandolin. I think we build a better mandolin than a traditional mandolin,” says Glenn, who markets his instruments as Moon Beam Mandolins. “I truly believe I’ve found a better way.”

The mandolin is a small, 8-string instrument that is tuned like a violin. Prior to the early 1900s, mandolins were deep and rounded like a bowl. In 1898, Orville Gibson patented a mandolin with a nearly flat back and arched top, inspired by the way violins are made. The Gibson mandolin quickly became one of the most imitated instrument designs in history.

“The body size, the body shape, the headstock shape — all those things that Gibson does with their scroll and their headstock — there’s a thousand builders out there all doing that same thing,” Glenn says. “They’re just copying. They’re not trying to better the instrument.”

Just 30 years old, Glenn has been making mandolins for the past 10 years. Initially, he faithfully copied Gibson’s designs. But now, having made more than 40 handcrafted instruments bearing the Moon Beam logo, he’s begun to distance himself from the pack of imitators.

Glenn carves relief into the scroll area of a mandolin.

Moon Beam mandolins differ from the Gibson formula in subtle ways. The body is imperceptibly larger. There are minor cosmetic differences. Glenn’s color offerings — or “illuminations” in Moon Beam speak — lean toward the wild side, with brilliant purples, reds and greens in addition to the traditional brown and black most builders offer.

Other distinctions are more pronounced. For example, Glenn says the body scroll that defines Gibson’s ornate F-style mandolin actually prevents the instrument from realizing its full sonic potential. Glenn’s design features a scroll that is actually part of the sound chamber.

“The traditional Gibson scroll is really thick and that’s all excess wood that’s taking away from sound waves. It’s a dead spot, right there in the mandolin,” Glenn says. “What I’ve done is the opposite. I’ve actually made it a functioning part of the instrument.”

The differences are not lost on Glenn’s customers.

Mike Bisetti is a Hollywood special effects man who has worked on such films as “Speed” and “Apollo 13.” He also is an amateur mandolin player and the proud owner of Moon Beam No. 35, an F-style instrument finished in Majestic Moon, Glenn’s vibrant purple finish. “It is the most incredible instrument — the richness of the tone, the sustain,” Bisetti says. “I can’t say enough.”

Glenn checks his progress while sanding the edge of a mandolin.

Bisetti learned of Glenn’s instruments when a co-worker brought a Moon Beam mandolin onto the set of a film. Bisetti played the instrument and was sold. “It was perhaps one of the finest sounding instruments I’d ever seen,” he says. “I was just awestruck with it.”

Bisetti immediately contacted Glenn through his Web site and placed an order. Although he says he was prepared to pay $8,000 for a mandolin, the Van Nuys, Calif., resident was pleased to learn that Glenn’s instruments were more affordable.

The basic Moon Beam mandolin costs $3,500. Upgraded woods, additional decorative embellishments or other custom features add to the bottom line. Even without elaborate ornamentation, each mandolin takes nearly 1,500 hours to construct. Just carving the top takes a week.

Glenn typically uses spruce, cedar or maple to build his instruments, but woods from fruit trees, such as cherry, apple and pear, are also used. Most of his wood is purchased from luthier supply houses but he can also tap into a treasure trove of aged woods he was given when he first began building instruments.

Holding a small plank of straight-grained sitka spruce, air-dried for 30 years before he received it, Glenn says, “This piece would be like a $500 upgrade on a mandolin, because it’s one piece. It’s big enough to make a whole top.

Glenn uses a tiny hand plane to remove material from the internal braces of a mandolin. Building a mandolin requires nearly 1,500 hours of labor.

“I don’t even know anybody else who uses stuff like that. It’s so rare,” he says. “This stuff is irreplaceable.”

Although Glenn’s instruments might seem expensive to the uninitiated, they’re actually a bargain in the world of hand-built mandolins. American-made mandolins typically cost $10,000 or more — often a lot more. Highly ornate instruments or top-of-the-line models bearing a popular musician’s endorsement sometimes sell for $25,000.

“That seems outrageous. You shouldn’t have to mortgage your house to get a good mandolin,” Glenn says. “My whole purpose in building these instruments was because I couldn’t afford one.”

Glenn built his first mandolin while attending the College of the Ozarks, near Branson. A music major, Glenn had played French horn and trumpet in high school but now was taken with the mandolin. He needed an instrument for his studies but neither he nor his parents could afford one. Instead, his father bought him a book on building mandolins.

With its carved top and intricate body shape, the mandolin is one of the most complex instruments to make. It’s hardly a project for a beginner. But with his father’s help, Glenn set out to do the improbable.

Bobbie Cirillo, Glenn's fiancée, installs a tailpiece on a Moon Beam A-style mandolin. Like the more elaborate F-style, the A-style mandolin was poularized by the Gibson company in the early 20th century.

“My dad has always been really handy with wood,” Glenn says. “He told me I could do it, and I did it.”

That first mandolin served Glenn well during college and carried him through part-time work as a stage musician, performing in Branson shows. But the instrument-building bug had bitten and Glenn continued to construct mandolins.

Glenn learned to carve the graceful arched top and tune the instrument’s internal bracing. He became skilled at shaping necks, bending thin wood strips for the instrument’s sides and inlaying the abalone that create his crescent moon logo — a shape he adopted initially because it was easy to carve.

“The quality of the instruments came rather quickly with me,” says Glenn, who has since trained his fiancée, Bobbie Cirillo, to help in the shop. “By my third one, they were really, really, really jam-up instruments.”

Since that time, he’s continued to refine his instruments by experimenting with different woods and perfecting his design.

Glenn plays one of his mandolins while accompanied by his father, Glenn Robertson, Sr., on guitar.

“Through time, I have grown as a luthier. And the instruments have grown,” Glenn says. “The sound, the tone, everything is getting more complex right now.”

Whether it’s their striking colors or the subtle differences in his designs, Glenn’s mandolins appeal to players looking for something a little out of the ordinary. Mickey Anderson of Hillsboro, Ore., was looking for just such an instrument when she spied a Moon Beam mandolin on eBay and contacted Glenn.

“He described it as a sweet-sounding instrument,” recalls Anderson. “That appealed to me. I’m a Celtic player so tone was very important.”

Currently, Glenn builds about 10 to 12 mandolins each year. Although he says he would like to increase his production, or at least speed up the time it takes to carve tops, he’s otherwise content with the way his business is progressing.

“I’m torn,” he says. “I could probably make 25, 30 a year, but then I wouldn’t have any time to play.”

The Moon Beam logo adorns each headstock.

Instead, Glenn says he hopes to continue to build a dozen or so mandolins a year, while branching out into other instruments, such as arch-top guitars and the mandola, a larger member of the mandolin family.He’s working on songs he hopes to record with his family and he continues to try to improve his instruments. And that, more than anything, is what he says drives him.

“It’s not about making money for me. It’s about building the best mandolin I can,” he says.

“It’s a really happy time for me right now because they’re developing into something beyond what you can find anywhere,” Glenn says of his mandolins. “I compare them to other mandolins, and they have the little something that’s different.”

For more information, call Glenn at (573) 686–6044 or log onto

Rural Missouri | June 2020 Issue

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