How To Tell If Your Guitar Has A Nitro Finish

How to Tell if Your Guitar Has a Nitrocellulose Lacquer Finish

Many guitarists appreciate the look and feel of a nitrocellulose lacquer finish. Often associated with vintage instruments, nitro finishes are known for their tonal qualities and aging characteristics. But how can you tell if your guitar actually has this coveted finish? Let's dive into several methods to identify a nitro finish.

Visual Inspection: Clues to a Nitro Finish

While not foolproof, visual inspection can offer valuable clues. Look for these characteristics:

Thinness and Subtlety:

• A nitro finish is typically thinner than modern polyurethane finishes. This means you might be able to see the wood grain more clearly, especially in the thinner areas. A polyurethane finish often presents a more "plastic" look, obscuring the wood grain.
• Check for subtle checking or crazing. These fine cracks in the finish are a hallmark of nitrocellulose lacquer as it ages and reacts to changes in humidity and temperature. While some finishes might mimic this, true checking is a natural characteristic.

Color and Depth:

• Nitro finishes often exhibit a more natural depth and richness of color. They tend to allow the wood's natural beauty to shine through more than polyurethane. Poly finishes can sometimes appear more uniform and less nuanced.
• Look for subtle variations in color and sheen. Nitro finishes can have a slightly uneven appearance, reflecting light differently in various areas – this is a sign of the finish's thinness and natural aging process.

The Smell Test: A Quick and Easy Method

While not scientifically accurate, the smell test provides a quick indication.

The Distinct Nitro Odor:

• Nitrocellulose lacquer has a distinct, somewhat sweet and slightly chemical odor. This smell is faint but noticeable, especially if you carefully sniff near areas where the finish is thin or has been worn down. This scent is much less pronounced in modern finishes. Caution: Be gentle and avoid inhaling deeply. The fumes, though usually mild, should still be treated with respect.

The Fingernail Test: A Gentle Approach

This method helps assess the finish's hardness.

Gentle Pressure and Observation:

• Gently press your fingernail against the finish. A polyurethane finish will usually feel very hard and resist any indentation. A nitro finish, being thinner and more delicate, might show a slight give or indentation, albeit a very subtle one. Be extremely careful as to not damage your instrument! This method is best employed on areas with already visible wear.

The Solvent Test: A Risky Business (Proceed with Extreme Caution!)

This is the most definitive test, but it carries significant risks. Only attempt this method if you are prepared for potential damage to your guitar's finish, and only on an inconspicuous area.

A Drop of Test Solvent:

• There are specialized test solvents which may be used. Apply a tiny drop to a hidden area, such as the inside of the back cavity. Observe the reaction of the finish. If it dissolves or shows significant softening, it's likely nitrocellulose. However, this can permanently damage the finish, making it highly ill-advised unless you have no other options and are comfortable with the potential consequences.

Conclusion: A Combination of Approaches

Identifying a nitrocellulose finish usually requires a combination of visual inspection, smell, and perhaps a very cautious tactile test. Remember, no single method is foolproof, and the solvent test should be avoided unless absolutely necessary. If you're unsure, it's best to consult a guitar luthier or expert for a professional opinion.