There’s nothing quite like a piece of wood furniture to bring a sense of elegance and timeless beauty into your home. However, crafting and restoring wood requires special care to ensure it lasts.
This is why it’s important to know the different types of wood finishes and how they protect furniture.
Varnish
Varnishing is one of the most important aspects of woodworking but it can also be challenging. It is important to take the time to understand the process and learn how to use it properly. In addition, it is necessary to know the different types of varnish available and each offer’s benefits.
A varnish is a clear protective coating applied to wood by brushing, spraying, or wiping. It has two components: solvent and solids. The solvent evaporates and leaves the solids behind on the surface of the wood, transforming it into something beautiful.
Penetrating wood finishes, like boiled linseed oil and pure tung oil, penetrate the grain and react with oxygen to cure. These finishes are a great choice for a natural appearance, but they may become tacky in humid weather.
Professional wood finishing uses film finishes like varnish and shellac to stay on the surface, protecting it from impact and moisture. These finishes are relatively quick to dry and are less toxic than some other types of wood finishes. However, they may be yellow with age and can crack when exposed to temperature changes.
Stain
An excellent finish can make all the difference to a woodwork project. A clear finish protects the wood from moisture and physical damage and can change the final product’s appearance. The type of clear finish you select will depend on your appearance, durability and ease of use priorities.
Staining is a common form of clear wood finishing that involves coloring the timber with pigments suspended or dissolved in a solvent. The colorant can be anything from natural colors to dyes to clear polyurethane varnish. Stains typically require multiple coats and must be sanded between applications.
A stain can give the woodwork a glossy look or can be made matte by adding additional layers of stain. The most popular stains include oil-based paints, which penetrate the wood without raising its grain, and water-based stains, which raise the grain but dry faster. Some stains also contain tung and other drying oils to enrich the timber’s appearance.
Wax
A good wood finish accentuates the natural grain texture, making the surface smooth and clean. It also offers a certain level of protection from water and sunlight, as well as physical damage, depending on the type of finish used.
Penetrating finishes, such as tung or linseed oil, work to protect from within the wood by soaking in and reacting with oxygen to harden. This can take days to cure completely. Other finishes, such as varnishes and shellacs, are film finishes that remain on the surface and require no sanding.
These are usually easy to apply and dry quickly, but they lack environmental or physical resistance to other finishes. They are also prone to scratching, which can lead to dull surfaces. Wood finishing is an art and science that requires a thorough understanding of the properties of wood, proper application, troubleshooting, and cleaning techniques. It is important to wear gloves, long pants, closed-toe shoes, and safety glasses during wood-finishing projects. Ventilation in the workspace is also recommended. A mask may be necessary for certain projects.
Lacquer
An ill-thought-out finish can turn an exquisite piece of woodwork into an eyesore. While many consider appearance to be most important when choosing a finish, other factors that can affect the outcome include protection from moisture and weathering and how easy the finish is to clean up.
Lacquer provides a shiny, hard protective layer that is very durable. It is generally applied with a sprayer and is quick-drying. It is also relatively easy to reapply over time if the surface starts to discolor or scratch.
The most common types of lacquer are nitrocellulose and acrylic. Like nitrocellulose finishes, acrylic lacquers are known for not yellowing over time and have a much lower toxicity. Some people also use CAB (cellulose acetate butyrate) acrylic lacquers that are more flexible and less prone to cracking “crazing” than traditional acrylic finishes.
Tung oil, a natural penetrating oil made from the seeds of the tung tree, and boiled linseed oil, a natural vegetable oil derived from pressing flax seeds, are also used for preserving wood. They may be mixed with other oils, resins and solvents to achieve a certain look or performance.
Oil
An oil wood may be your ideal choice for a natural finish with a soft sheen. Pure linseed and tung oils require long drying times. They also darken with time, which can alter the color of your project. They can be heated to form polymerized linseed and tung oils to speed up the process.
Blended oil finishes contain a mix of real oil and varnish or polyurethane resins. They are quick to dry and are typically lower in VOCs than linseed or tung oils.
As a general rule, the lighter the finish, the quicker it will dry and the more moisture-resistant it will be. However, it’s important to remember that no finish protects wood from liquid or vapor moisture, so humidity control should still be a priority.
