Although the differences between varnish and lacquer are fairly subtle, there are some contrasts between the two that need to be pointed out. These differences will help you decide what type of product to apply to a surface in order to achieve the best possible exterior finish.
What Is Varnish?
Varnish is a clear, hard solution that is principally applied to wood to give it a glossy finish while forming a protective film around it. Varnish consists of a resin, a drying oil, and a thinner or solvent. Since varnishes have very little color, they can also be applied over a wood stain to enhance the shine of the wood.
What Is Lacquer?
Lacquer is a type of solvent-based product that is made by dissolving nitrocellulose together with plasticizers and pigments in a mixture of volatile solvents. Lacquer also contains a solution of shellac in alcohol that creates a synthetic coating, causing it to form a high gloss surface. The name lacquer derives from the Portuguese name 'lac,' which is a form of resin expelled from certain insects.
Aesthetic Differences Between Varnish and Lacquer
Both varnish and lacquer provide shiny and glossy finishes to furniture and fixture surfaces. While lacquers can come in clear or a colored coating, varnishes tend to be completely transparent and are rarely produced in any other color. Flatting agents are often added to varnishes, which produce a semi-gloss or satin sheen finish, while lacquers are available with many different sheen levels, ranging from high gloss to ultra matte. This allows you to decide on a preferred finish.
Differences in Durability
While both varnish and lacquer produce hard and durable finishes, the plasticizers put into lacquer give it a more hard-wearing finish than varnish. Some lacquers can produce extremely hard finishes which not only look beautiful when painted onto woodwork but are also highly resistant to damage, particularly from acid, alkali, water, and abrasions. Because varnish is less durable, many people choose to use lacquer than varnish to finish woodwork projects.
Differences in Application and Drying
Whilst the process of application is similar, varnish is usually brushed on while lacquer is normally sprayed on. One of the main differences between varnish and lacquer is that the latter is much quicker to dry. Lacquer, due to its evaporating solvents, will always dry on a surface much quicker than varnish. As lacquer is naturally glossier than varnish, one coat is usually sufficient, while varnish may require several coats.
When lacquer is processed, it is dissolved in a highly flammable solvent that contains toluene or butyl acetate and xylene. To minimize the risk of combustion, lacquer is usually sprayed onto a surface inside a spray booth that vacates any overspray. Varnish is much less flammable and is typically brushed on, as noted before. One way of knowing the difference between varnish and lacquer is that if the product is prepared to be brushed on, it is usually varnish. If it is formulated to be sprayed on, it is usually lacquer.
Essentially, both varnish and lacquer can be applied to wooden surfaces to give them a glossy finish. However, because of the highly durable properties in lacquer, it also makes a good metal finisher. Consequently, lacquer is often baked onto the inside of food and drink cans.