Ignore Mother Nature at your peril

Guitars can be described as hellish contraptions—structures of high entropy, with an uncanny tendency to come apart even when left alone. To perform properly, they must be made of thin sheets of brittle material that inconveniently change shape in response to humidity. And yet, this same fiendish device must maintain perfect stability beneath the strings: a rise or fall of just a few thousandths of an inch can turn it from a musical instrument into a wall ornament. Still want to make guitars?

It’s a recipe for a nervous breakdown. My experience suggests guitarmaking is a calling where many apply, few are chosen, and fewer still endure. Those who do survive are the patient and steady ones—craftsmen who come to understand wood’s temperament: its strengths, weaknesses, limits, and whims. Those who ignore them eventually lose, playing a game impossible to win.

Wood: The Remains of a Living Organism

Wood once formed part of a living organism—a complex network of systems built from specialized tissues, each contributing to growth and survival. I like to think of a tree as a grand hotel or skyscraper: its trunk and roots are full of plumbing and conduits, while the leafy crown holds its rooms and offices. But unlike man‑made plumbing, these pipes are alive—living, breathing tubes of organic tissue.

Then come the demolition and salvage crews—the timber companies. They sever the trunk from the roots, lop off the crown, and haul away the commercially useful portion: a sap-filled cylinder of cellulose (fiber) and lignin (natural glue), mixed with sugars, minerals, and countless chemical compounds. Four-fifths of that mass is water—more akin to a fibrous, elongated watermelon than a beam of wood.

Cutting It All Up

At the sawmill, massive band saws divide the log according to its intended purpose. Most ends up as pulp, but a fraction—its best part—is sawn into large blocks for furniture, building materials, or veneers. Spruce or cedar intended for instruments is cut differently: less efficient but yielding the most vertical-grain wood, the most stable and strongest configuration for softwoods. Hardwoods, though less predictable, are similarly prized when cut with near-vertical grain.

The finest hardwoods are sliced into flitches—long, thin sheets kept in their original order, like slices from an egg cutter. Instrument makers love flitches; matching wood becomes easy, and uniformity is ensured.

Air Seasoning vs. Kiln Drying

When freshly cut, a plank is still four-fifths water. Two-thirds of that moisture, called free water, lies in the sap within the cell tubes; the rest is bound water, trapped in the cell walls themselves. The wood is weak, slimy, and dimensionally unstable—useless until both types of moisture are removed.

Free water is held by capillary action and leaves easily; stand the plank upright and watch it ooze. Bound water, however, demands patience—it evaporates only through time and exposure, typically one inch of thickness per year. If that’s too long, you can use a kiln: a giant steam oven that speeds up the process in weeks. Wood technologists claim kiln-dried and air-dried wood are identical, but most of us luthiers prefer nature’s way—gentle, unhurried, and untraumatized.

Case Hardening

Left unattended, wood begins to deteriorate. Moisture evaporates fastest through the ends, where the cell pipes are exposed. As outer surfaces dry and shrink unevenly, they can seal in a wetter core, creating case hardening—a disastrous condition where the exterior locks in moisture and cracks appear. To prevent it, seal the ends with paint or wax to slow evaporation, and stack the wood in a shaded, well-ventilated space so drying remains uniform.

Flitch Cutting

Cutting the log into thin sheets immediately is another solution. Thin wood exposes a greater surface area to volume, allowing it to dry evenly and naturally in a few months—faster if stacked properly and lightly ventilated.

Is the Wood Ready?

You’ve bought your flitches or planks, and they’ve just arrived in your shop. Should you start cutting? Absolutely not. Even well-seasoned wood continues to absorb and release moisture, expanding in humid weather and shrinking when dry. This tendency has led some to call wood a “living” material—an appealing but misleading notion that has inspired countless misguided attempts to “feed” it oils and polishes.

You may not know the wood’s previous environment. It must acclimate to yours before you begin cutting or gluing. Store it for months, ideally in a part of your shop with stable temperature and humidity. A dry closet or windowless room is ideal. A simple test helps: place your palm on the wood. If it feels cool, it likely still holds too much moisture; if it feels neutral, it’s probably ready.

Expansion and Contraction of Seasoned Wood

Green wood merely shrinks as it dries. Seasoned wood, however, expands and contracts to maintain equilibrium with the surrounding air—always across the growth rings. Vertical-grain (quarter-sawn) wood widens or narrows evenly, staying flat. Students sometimes panic when a seasoned soundboard curls on the bench. “It wasn’t seasoned,” they claim. I flip it over—and in hours, it flattens. The shielded underside simply dried at a different rate.

Some luthiers hang plates like bedsheets for even exposure; I don’t bother, since minor curling stays within the wood’s natural resilience. Once braced, it stabilizes.

Before using any wood, it must acclimate to your shop’s conditions. More importantly, when closing a guitar body, the humidity should be midway between the environmental extremes the guitar will face. If 5% and 90% are the limits, glue up around 40–45%. That way, the wood only strains halfway in either direction. In my New England winters, I raise shop humidity to 50–60% when building for tropical clients.

This practice, along with arched braces that let plates flex rather than crack, has spared my instruments from climate damage for two decades. Still, vigilance is essential—you can never fool Mother Nature.

Proper Care Guidelines

Finally, I include my “Proper Care Guidelines” with every new instrument. My relationship with each client continues long after the sale: I’ll repair any genuine flaw in my design or construction, while the owner agrees to follow the care instructions. If neglect is evident, repairs are charged accordingly. Of about 500 instruments I’ve built, only five or six have needed repairs for faults—plus a dozen free neck resets I deemed prematurely necessary.

Would you like me to make this version slightly more conversational (preserving the personality of the original voice) or more formal and polished for publication?