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Shellac and lacquer are common wood finishes that can be applied by any DIYer with the right technique. But how do you decide between them?
In this article, we’ll explain the properties, history, and applications of each finish. Then, we’ll review the similarities and differences before revealing the major differentiating factor. Finally, you’ll learn when to use shellac, when to use lacquer, and which is better.
What Is Shellac?
Shellac is a liquid coating made from sticklac resin combined with denatured alcohol. Sticklac is a naturally occurring secretion of the lac beetle.
This sticky substance is farmed from trees, usually in India, before being processed to remove debris. The clarified sticklac is then dried into discs or flakes.
The discs or flakes become shellac when mixed with denatured alcohol. Changing the ratio of resin to alcohol changes the thickness of the shellac.
A ratio of two pounds of resin to one gallon of alcohol is called a two pound cut, and this is the blend most frequently sold in stores. Resin products and denatured alcohol can also be purchased separately and combined at home
Shellac has been used for thousands of years. It became the most popular finish for wood in the 1880s until the rise of lacquer in the 1920s. It is popular due to it’s quick dry time, durability, and non-toxicity.
Shellac can be applied with a brush, but it is more commonly applied with a rubbing pad using a technique called French Polishing. The result is a high-gloss finish that enhances the natural grain of any wood.
When dry, shellac is highly reflective, resulting in a glossy sheen. Steel wool can be used to scuff the surface of shellac to dull the finish, resulting in a more matte look. The color of the resin affects the color of the finish. Most shellac is amber, golden, or reddish brown.
It can be used on any kind of wood and applied to most surfaces. A common saying in woodworking is ‘shellac sticks to everything and everything sticks to shellac’. Although it dries quickly, mistakes are easy to fix simply by adding another thin coat of shellac.
Each coat of shellac dissolves into the one below it, building a smooth and even glossy finish. Best of all, there is no need to sand between layers of shellac.
What Is Lacquer?
Technically, shellac is a type of lacquer. The term originally referred to any finish made by combining resin with a solvent and which dries through evaporation.
Today, lacquer usually refers to synthetic finishes made from combinations of various polymers and solvents. Nitrocellulose, CAB, urushiol and acrylic resin can all be used to create lacquer. There is also another product called catalyzed lacquer, which relies on chemical additives and cures to a super-hard finish.
Lacquer dries to a hard, clear, and extremely shiny finish. Pigments can be added to change the color of the finish. It is combined with lacquer thinner to produce various concentrations that are used at different parts of the process.
The ratio of lacquer to thinner is dependent on the weather and the application method, with a thinner lacquer being used when lacquer is applied with a spray gun, to avoid clogging the nozzle.
Each layer of lacquer adheres to the one below it, making it a difficult and painstaking finish to apply smoothly, as each layer must be perfect before another can be applied. Otherwise, drips and stippling will be carried out into the final coat.
Sanding between coats of lacquer and wiping well with a tack cloth is the best way to prepare for an additional coat.
Shellac vs Lacquer
Now that you understand what lacquer and shellac are, you’re ready to compare these two popular and durable finishes.
Since shellac is technically a type of lacquer, these two finishes have many things in common. They are formulated in similar ways, can each be revived rather than refinished, and harden via the same process.
Both shellac and lacquer are formulated by dissolving a solid in a solvent. For shellac, the solid and solvent are always the same: sticklac resin and denatured alcohol. Lacquer can be created from different combinations of solid and solvent.
The solids used in lacquer could be acrylic resin, nitrocellulose, uruishiol, or cellulose acetate butyrate (CAB). A mix of solvents is often used, so lacquer could contain any of the following chemicals; acetone, ethyl acetate, ethanol, methanol, toluene, xylene, and butyl acetate.
Both shellac and lacquer can be ‘revived’ when they start to look dull, scratched, scuffed, or cloudy. Shellac is revived via the application of more shellac, mixed with a generous amount of denatured alcohol. Multiple coats may be needed to fully restore badly damaged shellac, including cracked surfaces.
For lacquer, no additional finish is used. Instead, a light coat of lacquer thinner is brushed onto lacquered wood, wiping away any cracks or scratches.
Mechanism of Action
Unlike varnish or polyurethane, both lacquer and shellac are non-curing finishes. This means they do not undergo a chemical hardening process when exposed to oxygen. Instead, they dry through the evaporation of solvent. The exception to this would be catalyzed lacquer, which includes a chemical hardener.
While lacquer and shellac are similar, they are not the same. They differ in the level of protection they offer, their toxicity, and how many coats are needed to finish the job.
Lacquer is hard and durable, providing robust protection for the surface it covers. Shellac also protects and preserves, but it is significantly less durable. Shellac is not waterproof, while lacquer is impervious not only to water, but also to most household chemicals.
Many consumers are concerned about the amount of VOCs off-gassed by a finish, both during application and after the finish has dried. Shellac emits minimal VOCs. Lacquer’s VOC emissions are much higher.
Number of Coats
Lacquering generally involves applying three or four coats of finish. The lacquer must fully dry and then be lightly sanded and cleaned before adding another coat. Shellacking usually includes at least ten coats of finish.
Lacquer is usually sprayed onto wood or MDF using a paint sprayer powered by compressed air. Shellac is most-frequently applied by hand, using a wad of cotton. Either finish can be applied with a brush, but this method is less common.
Major Differentiating Factor
Shellac has one important feature that no other finish can match, including lacquer: It seals in odor. Musty and dusty drawers benefit from a quick coat of shellac to prevent smell transfer to clothes that are stored within. Wood that has been exposed to smoke or animal urine and would otherwise need to be discarded can be given a new life with shellac.
If you have a stinky workpiece, but your heart is set on lacquer, don’t despair. You can use shellac as a seal coat, and then switch to lacquer to build the finish.
When to Use Shellac
Use shellac for interior furniture, and food serving items. Shellac is also great for antique wood furniture.
Shellac is best for wood that will not see heavy traffic. While it has protective qualities and will resist minor scratches and scuffs, it is not the most durable or hardest finish available.
Shellac is water-resistant, but not water-proof, so it cannot stand up to weather and should not be used outdoors. It also suffers from water rings from the condensation in your glass.
Because shellac is non-toxic, and so mild that it can be used as a food glaze, it is the perfect choice for finishing wooden food service items.
Shellac is often marketed as ‘salad bowl finish’ for this reason. It gives wooden bowls and cutting boards a lustrous glow that will last for years. Take care not to soak wooden kitchen implements that are coated in shellac as the finish will become cloudy after prolonged exposure to water.
Shellac is the finish of choice for stringed instruments such as guitars or violins that are made from wood. Unlike shellac, a thick varnish can change the sound of the instrument, so the much thinner profile of shellac is preferable for this purpose.
When to Use Lacquer
Use lacquer for kitchen cabinets or anywhere you want an intensely high-gloss finish.
Lacquered kitchen cabinets are both beautiful and durable, making your kitchen gleam. Paint can be added to lacquer to produce a vibrantly colored, opaque, and highly-reflective surface.
Nitrocellulose lacquer has an amber tint that enhances the grain and appearance of many medium and darker colored woods. It is not the best choice for light-colored woods. Instead, when you’re looking for a completely clear coat, choose a lacquer formulated with acrylic resin.
Urushiol-based lacquers produce an incredibly lustrous finish that is popularly used in Japanese woodworking. Urushiol is present in poison ivy and poison sumac, and can cause immune reactions ranging from mild rash to severe anaphylaxis.
Should you choose to work with urushiol lacquers, make sure you protect your airways, eyes, and skin from coming into contact with the lacquer when wet. Once properly cured, you should be able to safely interact with the lacquered surface.
Which is Better, Shellac or Lacquer?
Lacquer is best when you need heavy-duty protection, intense colors, or high-gloss shine, and are willing to plan around the release of significant amounts of VOCs.
Shellac is the better choice when you’re looking for a gentler, non-toxic finish that offers less protection.