Guitarists are one of the most impassioned groups of hobbyists on the planet. One thing that’s contentious among some of us is, believe it or not, the finish.
While most players won’t have a clue what the finish is, the true geeks among us know all about it.
In this article, we discuss the main types of guitar finishes and offer up some advice around which is best.
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What Does a Guitar Finish do?
There are two main reasons for applying a finish to a guitar: protection and looks.
Starting with protection, most of a guitar’s anatomy (i.e. its body, neck, headstock, etc.) is made from wood, and wood is prone to warping in extreme conditions (extreme humidity or cold) or simply with age (note: there are products that help to manage humidity levels, but the choice of finish is important to get right from the outset).
A finish helps to seal away all this quality tonewood from interfering elements and to protect it from everyday knocks and scrapes.
Secondly, finishes also give your guitar a specific style or look, whether that be by highlighting the woodgrain pattern for a classical look, or by adding a thick protective layer for a more vibrant, modern vibe.
Some even age over time and produce slight imperfections, which can create a cool grunge type of aesthetic.
Types of Guitar Finishes
Oils and Waxes
These are the oldest guitar finish materials and have become less popular over time, due to the lack of protection that oil and wax offers. The wax itself tends to be a refined beeswax, whereas the oil usually comes from natural plant-based sources.
That said, neither oil or wax changes your guitar’s tone much in comparison to thicker lacquers, so they are a great option for acoustic instruments that rely on tonewood for their sound, rather than an amp’s EQ.
In terms of aesthetic, oils and waxes can enhance your guitar’s natural woodgrain nicely and are lightweight, which is handy if you’re carting your instrument around with you all the time.
Oil and wax coatings are easy to apply yourself, however, they will require the body wood to be prepped properly beforehand and some time to dry.
You can actually use a combination of oil and wax, by applying the oil coat first and a final wax finish once the oil has set.
Shellac, is a natural resin produced by the female Lac Bug, native to Thailand and India. This type of finish enhances a guitar’s natural wood grain pattern by forming a lightweight, glossy coating.
Shellac doesn’t affect your guitar tone much either, which makes it a great option for classical instruments that need as much natural sound as possible.
As a material, Shellac is fairly easy to apply, so long as you have at least a week spare to wait for it to dry.
The sealant itself can be applied using a paintbrush or spray, though guitar luthiers often prefer to use a spray and polishing pad to ensure the varnish has been applied evenly.
Once set, Shellac is tougher and glossier than an oil or wax coating, so it offers slightly more protection.
Nitrocellulose Lacquer (‘Nitro’)
This is a finish made from plant-based cellulose combined with a nitro-solvent.
In regards to looks, ‘nitro’ tends to wear away in places, as the solvent evaporates. This creates a sort of worn grungy look, which is cool if you play that style of music.
In terms of protection, however, this finish isn’t quite as tough as polyurethane or polyester, mainly due to the nitro-solvents evaporating over time and the cellulose tending to crack in extreme environments.
The good thing about nitrocellulose is that it can be patched up in areas that are becoming distressed easily, and lets the guitar retain most of its original wood resonation.
In particular, this finish doesn’t fully set like polyurethane and polyester, so it keeps some flexibility and gives the guitar a warmer overall tone.
Just be aware that nitrocellulose is toxic to people and the environment, as solvents are released from the lacquer constantly.
This is a plastic, urethane-based finish which was designed in Germany and introduced to the industry in the 1950s.
Polyurethane became commercially successful thanks to it being safer, cheaper and easier to apply than nitrocellulose, requiring just two layers to produce a glossy, even finish.
Polyurethane also ages well and offers more protection than all the coatings we’ve mentioned so far, so it is a popular choice among modern guitar luthiers. In fact, this finish is so strong it’s often used to protect gymnasium or office floors!
When it comes to aesthetics, this material gives a clear, shiny coating to your guitar, so it will suit anyone that doesn’t want to play something beaten up looking.
There are, however, different types of polyurethane available, with brands like Fender using a thinner satin and a thicker gloss urethane on different guitars.
This is another plastic-based finish that became popular among guitar luthiers like Fender in the ‘70s.
The material itself sets very hard and is usually applied as a thick layer to protect the instrument.
Polyester ages well, thanks to its durability and provides the guitar with a sharp, colorful look, without cracking or wearing away in places.
In terms of tone, this material doesn’t tend to affect your guitar’s sound much and preserves most of the pickup tone.
Another bonus is that polyester isn’t as toxic as nitrocellulose either, as it doesn’t contain solvents or other harmful ingredients.
Companies tend to use polyester regularly because it’s cheaper than lacquers and easy to apply as a spray.
In the early days, companies tended to spray on polyester in a very clumsy manner, which results in a thick finish that looked unappealing and drained your guitar tone.
Overall a guitar’s finish should be an important consideration that affects which guitar you buy or use.
For example, if you want something lightweight that keeps your instrument’s tone, then an oil or shellac-based finish would be a good choice. These also look great on bare wood and enhance the grain nicely.
If you want something with a little or a lot more protection, then go for a polyurethane or polyester-based finish. These materials age well and won’t warp in extreme environmental conditions.
Additionally, plastic-based coats provide a vibrant, bright aesthetic, which works well with painted guitars.
Finally, there’s also the option of using a nitro lacquer.
Just remember, this stuff is toxic to work with before and after it has set. That said, it is a good middle man between oils and plastic-based finishes, seeing as it sets harder than shellac, but keeps more of your guitar’s original tone than polyester/ polyurethane.