Nitrocellulose vs Polyurethane Guitar Finish: Which Should You Buy?

The guitar finish debate has been running for decades, and it generates more heat than almost any other topic in acoustic guitar circles. On one side: players and luthiers who insist that nitrocellulose lacquer (nitro) is essential for great tone. On the other: skeptics who argue that polyurethane (poly) is just as good and far more durable. Both sides have valid points. Here is the complete picture.

What Is Nitrocellulose Lacquer?

Nitrocellulose lacquer is a solvent-based finish that was the industry standard for guitar finishing from the 1920s through the 1960s. It is applied in very thin coats, dries quickly between applications, and continues to cure and shrink over time as the solvents off-gas. Classic Martin and Gibson acoustics from this era all used nitrocellulose, which is part of why vintage instruments from the 40s and 50s are so prized today.

Nitro remains the choice of premium acoustic guitar makers for several reasons. It is thin — often just a few thousandths of an inch thick in total — which means it does not form a rigid shell around the wood. The wood can vibrate freely, breathe seasonally, and develop the tonal complexity that comes from years of play and aging.

What Is Polyurethane Finish?

Polyurethane finish became common in guitar manufacturing starting in the 1970s, driven primarily by practical advantages: it is cheaper to apply, dries faster, requires less skill to achieve a consistent result, and produces a much harder, more durable surface. Most factory-produced acoustic guitars in the sub-$800 range use polyurethane or its close relative, polyester.

Poly finishes are applied thicker than nitro, which creates a rigid layer between the player's hands and the wood. This is great for durability — a poly-finished guitar will resist dings, scratches, and humidity changes far better than a nitro-finished one. But that same rigidity is acoustically constraining, limiting how freely the wood can vibrate.

Does Finish Actually Affect Tone?

This is where the debate gets complicated. The honest answer is: yes, but the degree depends heavily on how thick the finish is applied. A thin poly finish, carefully applied, is acoustically very close to a thin nitro finish. A thick poly finish creates a measurable difference in resonance and sustain.

Most factory-produced guitars use thick poly because it is forgiving to apply and requires no special handling. Premium guitars — whether they use nitro or thin poly — are finished carefully by hand, which is why they often sound better than similarly priced factory instruments regardless of which finish type is used.

At Fency Music, every guitar in the Fivcil MIC series uses hand-applied nitrocellulose lacquer precisely because we believe the thickness and quality of the finish matters. This is one of the areas where we invest beyond what most guitars at this price do. Browse the full nitrocellulose finish guitar collection to see the lineup.

How Nitro Ages vs How Poly Ages

This is where nitro and poly diverge most dramatically, and for many players, it is the deciding factor. Nitro ages visibly and beautifully. It develops checking (a network of fine surface cracks), yellows over time, and wears naturally at high-contact areas: the back of the neck, the forearm contour, and the pick guard edge. This is what relic guitars are meant to replicate, and it is why vintage guitars with original worn nitro look the way they do.

Polyurethane does not age this way. It stays hard, clear, and essentially unchanged for decades. Some players prefer this — the guitar looks new for its entire life. But it never develops the patina and worn-in character that nitro-finished instruments acquire.

From a resale and collector standpoint, original nitro finish in good condition is far more desirable than poly on vintage and premium instruments. This matters less for new guitars, but it is worth knowing if you are thinking about long-term value.

Durability: The Honest Trade-Off

Nitro is significantly less durable than poly. It is more susceptible to checking from temperature and humidity swings, scratches more easily, and requires more careful storage (some rubber guitar stands and straps contain chemicals that react badly with nitro and cause finish damage). If you are the kind of player who gigs hard, travels frequently, or is not careful with gear, poly is more practical.

Nitro is the right choice for players who value tonal quality, plan to age the guitar naturally over time, and are willing to be a bit more careful with storage and handling.

Which Should You Buy?

Buy a nitro-finished guitar if: tonal quality and aging character matter to you, you are buying a guitar you plan to keep for a long time, and you are comfortable with the care requirements. Every guitar in the Fivcil MIC series uses nitrocellulose lacquer, which is part of why they perform above their price point. See the full nitro finish collection.

Buy a poly-finished guitar if: durability is a priority, you are hard on gear, or you are buying a first instrument and the finish matters less than the playability and value. Our best acoustic guitars under $500 include solid options regardless of finish type.

For most serious players who care about tone, nitro is worth the slight extra care. For working musicians who need a guitar that can take abuse, a quality thin-poly instrument is the more practical choice.