Boom! You've just blown up your chemistry lab by combining nitric acid with cellulose, creating nitrocellulose lacquer. Originally created to deliver a high quality lacquer for furniture and cars, nitrocellulose morphed into the be-all and end-all for vintage guitar finishes. In commercial uses, nitrocellulose with nitrogen registering below 12.3 percent is used for lacquers, coatings and inks. When the nitrogen content is above 12.6 percent, it is considered an explosive. Nitrocellulose isn't toxic but be sure to wear eye coverings when playing with these elements because they are highly flammable. At one time, pool balls were covered with a film of nitrocellulose with a high nitrogen content. Imagine a Wild West pool hall when the ball was hit with a cue stick—everyone ducked for cover. That experiment didn't last long!
But nitrocellulose does have positive uses. High-gloss automotive finishes often are made with nitrocellulose lacquer. And for those who fight warts and aren't concerned about body parts exploding, Compound W contains nitrocellulose to carry the salicylic acid used to treat warts. Just check the label for the ingredients.
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A plastic for the ages
When cellulose was first extracted and experimented with, the organic compound found in the cell walls of plants and algae was made up of carbon, hydrogen and oxygen and was the most abundant organic polymer on Earth. Taking cellulose a step further, in 1862, a scientist named Alexander Parkes combined cellulose with nitric acid and a solvent, and voila! The first man-made plastic was invented. It was similar to TNT or dynamite, so adjustments had to be made.
A scientist named Edmund Flaherty at the DuPont Company, known for its progressive chemistry laboratories, invented the lacquer version of nitrocellulose in 1921. What he found was a liquid that could be applied with a spray gun onto the target, and the volatile solvent thinner would dissipate almost immediately, leaving a clear-coat layer of nitrocellulose solids behind. This added to the durability of the surface as well as the flexibility of the nitrocellulose lacquer.
Henry Ford of the Ford Motor Company heard about the invention and realized a way his original cars could be painted in pigments other than the original black. The new line of lacquers was fast-drying, could be applied with spray equipment, was tougher and more scratch-resistant than shellac and opened the color palette to a variety of shades. Nitrocellulose lacquer was a basic in the automobile industry into the 1950s when it was replaced by acrylic lacquer.
Uses for guitar finishing
At the same time, furniture and musical instrument manufacturers realized the many uses for the clear lacquer poly finish, and by the 1960s, just about all collectible and acoustic guitar bodies left the factory wearing a topcoat of the clear lacquer. A base coat is applied followed by subsequent applications, melting the thinners of the base coat and allowing the additional coats to bond. This creates depth and luster to the coating and allows the surface to breathe.
Is a Nitro Finish Worth It?
- The application of nitrocellulose lacquer is a time-consuming project requiring many repeats in order to produce the high-quality results that vintage equipment requires.
- Sanding and polishing to a high gloss was manual before advancements were made with the product.
- Finishes tended to turn yellow or crack. Vintage finishes were thicker than the finishes of today.
- OSHA, noting the toxicity of the finish, forced manufacturers to rework their formulas. The result was a less appealing wood finish yielding a guitar lacquer that muffled the original tone.
Fender and Gibson finishes
Guitar companies were using standard off the shelf nitrocellulose lacquers, all of which had different formulations. The original versions were similar to acrylic lacquer, where colors faded and surfaces cracked. The vintage nitro lacquer appears to look more like tea, while the modern version is similar in appearance to canola oil. The vintage nitrocellulose lacquer finishes "gassed off" quickly, meaning they lost viscosity and got thinner and thinner over time, unlike the new finishes, which are softer. However, Fender and Gibson used nitrocellulose lacquer almost exclusively on their range of electric guitars in the 1950s and 1960s.
Fender Finishes- Nitro
* Nitro blends well with the guitar's natural grain.
- Repairs easily.
- Better sound to the guitar as the finish allows little restraint of sound.
- Can crack and yellow.
- Finish gets thinner and more brittle as it ages.
- Still used on its American Vintage series.
- Applied in Mexico due to strict American EPA rules.
In search of a less costly guitar finish, Fender started using Fullerplast, a clear gloss polyester sealer. The bodies of the guitars were dyed yellow, the Fullerplast was applied and then the nitrocellulose was sprayed onto the guitar's body. Nitro was expensive. Fullerplast saved the manufacturer money. However, Fender began playing with the finishes to compensate for the luster achieved with nitrocellulose, as did Gibson.
Gibson Finishes - Nitro
- Gibson uses Nitro on all its USA made electric guitars, including their popular Les Paul Series.
- Nitro gives Gibson guitars a "wetter" feel.
- Allows the wood to expand and contract naturally.
- Requires 7 main coats, plus 2 more coats after drying and sanding.
- As it ages, light cracks and "checking" develop, giving the guitar a vintage feel.
- Nitro's softer finish makes repairs to the surface easier.
When guitar shopping, don't be fooled by Gibson's use of the word "poly" when describing the metallic finishes. They're really acrylic. Spraying nitro over acrylic and poly bases still continues on their less expensive lines. It's always worth investigating whether the nitro finish is actually nitro!
Finishes into the 21st century
Not too many people own professional spraying equipment, and handling nitro is dangerous in the wrong hands. Several companies in the United Kingdom supply aerosol sprayers for the application of nitro, but exposure to the highly toxic particles can be dangerous to your health. Extraction fans and breathing masks are a must. While vintage finishes on guitars are legendary and expensive, what you don't want to see or hear is ... BOOM!