Nitro vs. Poly – Which Guitar Finish Is Better?

There are many subjects that split opinion among guitarists. And believe it or not; guitar finish types is one of them. Although most players aren’t too concerned about the type of finish that’s been applied to their guitar, for some players and luthiers – it’s actually quite contentious.

Two main sides split this debate; those that favour old-school nitrocellulose lacquers, and those that are content with modern polyester and polyurethane finishes. Traditionalists find the former more appealing, as nitrocellulose was used almost exclusively on vintage instruments from the golden era of guitar production. But there are many guitarists that prefer poly finishes, as they are more resistant to wear and have a glossier look.

In this piece, we’re going to shed some light on these two types of guitar finish. Explaining their advantages and disadvantages, as well as the effect that they have on the sound of a guitar; we hope that by the end of this article you’ll have a greater understanding of their differences.

Nitro Guitar Finish

Nitrocellulose lacquers have been around for almost a century; originally used for acoustic instruments, saxophones and even cars. This finish later became a popular choice for Fender and Gibson in the ’50s and ’60s, who used it almost exclusively for their electric guitars. Fender also experimented with acrylic during this period, but nitrocellulose was generally favoured for finishing guitars as it could form a nicer gloss.

Regarding its content, nitrocellulose lacquer is mostly solvent-based and comprised of plant-based substances like cotton, mixed nitric and sulfuric acids. The nitrocellulose element serves as a binding agent, which is then mixed with solvent to enable a conventional spray finish. The solvent used is acetone; a highly-flammable substance that ultimately forms the shiny lacquer.

A nitrocellulose guitar finish is applied multiple times over several days, with each coat essentially melting the previous one. This process eliminates the need to sand between layers. After full application, the solvent chemicals are left to fully dissolve; leaving a dry resin-like texture. This is then hand-buffed and sanded until a glossy finish is achieved.

Pros & Cons of Nitro Guitar Finishes

Nitrocellulose is considered to be more porous than polyester or polyurethane, with a thin, smooth and somewhat slippery texture that isn’t quite as solid or constrictive. Many purists and luthiers therefore believe that a nitro finish allows a guitar’s wood to breathe, yielding a more open sound and greater sustain.

Although nitrocellulose lacquer may give a guitar an airier sound, its softer texture does make it susceptible to cosmetic damage. This means that dings and scratches are more visible on guitars with nitro finishes, and much easier to inflict. A nitrocellulose lacquer also wears away over time, causing dulling in areas where you make regular contact with your guitar; such as the lower bout where your forearm rests. Nitrocellulose also yellows with time, especially when exposed to excessive sunlight.

Apart from the above, small cracks can appear in a nitro finish after several years too. This occurs when a guitar is regularly exposed to differing temperatures, as changes in climate causes wood to expand and contract. And as we explained, nitrocellulose lacquer is thin and slightly porous, meaning that the wood it’s applied to is more prone to this issue.

Which Guitars Have Nitro Finishes?

These days, this type of guitar finish is used almost exclusively by Gibson and Fender’s Custom Shop divisions. As these departments mostly produce premium time-honoured instruments, they therefore use nitro finishes to recapture the essence of their older vintage models. Nitro lacquers are also typically used on more expensive guitars as the application process is time-consuming and requires several layers. They must also be carefully hand-buffed and sanded at the final stage to ensure a consistent, professional quality.

What’s interesting, though, is that a lot of high-end guitars are deliberately damaged and worn to create an aged look. In the industry, this is referred to as“relicing”; a practice that has become more common from the growing demand for older-looking guitars. As nitrocellulose is easy to damage and manipulate, most relic’d guitars you’ll come across will have this finish. Attempting to relic a poly-finished guitar would not look very convincing at all!

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Poly Guitar Finish

Polyurethane and polyester guitar finishes are considered the industry standard; the modern norm if you will. In mass guitar production, poly finishes largely replaced nitrocellulose lacquers from the late ’60s onwards. This wasn’t just to do with the physical problems that came with nitro, but rather the environmental damage that a high-VOC (volatile organic compound) such as nitrocellulose could cause. In the 21st Century, the use of nitrocellulose is therefore strictly regulated and monitored.

Low-VOC poly finishes are considered safer to use and don’t pose as much of a threat to the environment. As polyester and polyurethane is based on synthetic resin, no solvents remain after their application to a surface; hardening completely. This means that multiple layers of polyester or polyurethane aren’t necessary, unlike nitro finishes that require many. Poly guitar finishes are therefore much easier to use and quicker to apply.

Pros & Cons of Poly Guitar Finishes

Apart from their relative simplicity, poly guitar finishes are also a lot thicker and stronger than nitrocellulose, with a glossier look. Their strength makes them more resistant to cracks as they cover the instrument more successfully, lessening the chance of wood expansion/contraction. But because of this, some therefore believe that poly-finished guitars sound somewhat neutered and less acoustically resonant, with reduced sustain.

Polyester and polyurethane guitar finishes are also more resistant to general wear, meaning that scratches and dings are harder to see and inflict. Poly finishes can remain shiny even after decades of use, and don’t fade away in the areas that you’d typically make contact with. If you want your instrument to look new forever, then a poly finish is superior to nitro lacquer. Of course, you’d still need to take good care of your guitar, and our range of electric guitar care products can help your instrument to maintain a showroom look! Check out our Guitar Cleaning Guide here.

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Which Guitars Have Poly Finishes?

Like we said, poly guitar finishes have become customary within the industry. This means that most mass-produced guitars you’ll come across will feature polyester or polyurethane finishes. The fact that it is simpler and faster to apply than nitrocellulose keeps costs down, while of course, offering a shinier look and greater durability.

Although nitro finishes are more synonymous with premium instruments, it doesn’t mean that poly finishes scream “cheap”. Poly is used on instruments both affordable and expensive, from beginner guitars to premium hand-made instruments.

Want to learn more?

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