Wood Finishing Types And Techniques

By Ed

June 19, 2023

100

Your project is “done.” Every board has been perfectly planed, the glue is set and dry and each nail and screw are placed perfectly. You stand back from your work and breathe a sigh of admiration and relief, until remembering that your work is not done just yet.

In fact, you have yet to start the finishing phase of your project. Now you have to consider what techniques you will be implementing to truly complete this project!

Woodworking Project Phases

Woodworking projects-whether they are large scale custom furniture builds or smaller cutting board creations-can be broken into two phases: building and finishing.

The building and making of the project includes the chopping, the planning, the cutting, the gluing, and the nailing to bring wood pieces back together.

Finishing is done by applying a protective layer to said projects outer surface. Not only will the protective layer of finish change the appearance of the wood by manipulating and highlighting its color and character, but it will protect the woods surface from dirt, scratches, and moisture.

Types of Wood Finishes

There are two categories that wood finishes can be broken into:

Penetrating finishes penetrate the fibers of wood and harden. They offer a more natural look to your finished workpiece and can be applied easily using a rag or brush.

While they offer a beautiful and natural look and color, penetrating finishes do less to protect the surface of your project from tarnish. Penetrating finishes include oil-based finishes like linseed oil, tung oil and Danish oil.

Surface finishes obtained their name for being applied to the outer surface layer of a workpiece. These finishes create a strong protective layer and have high resistance to wear and tarnish.

The Best Finish for Project

Deciding what the right finish is for your workshop project can feel like a daunting task. With so many types of wood finishes on the market and with each craftsman having an opinion on what is best, it is hard to know what is right for you.

When determining a wood finish type for your next project, important factors to consider are protection needed, durability of the finish, ease of application and the aesthetics you are seeking.

To properly consider your options, here is what you need to know about the different wood finishes on the market:

Penetrating Finishes

Linseed Oil: this oil finish offers a matte to shiny appearance and enhances your woods natural color with a warm glow.

Linseed oil is easy to apply with a brush or cloth, though its drying time is significantly longer in comparison to other wood finishes. Overtime, linseed oil will darken and alter the color of whatever project it is applied to.

Tung Oil: also known as China wood oil, as it is derived from nuts of tung trees native to China, this all-natural oil adds a beautiful golden color and glossy finish.

Tung oil hardens when it is completely dry, though its dry time is incredibly slow. One of the greatest advantages of tung oil is its waterproofing properties and hard layer of protection, while its greatest disadvantage is application time.

Danish Oil: Danish oil will vary from manufacturer to manufacturer, as it is a cocktailed combination of tung oil, linseed oil, varnish, mineral spirits and more. It is an ideal oil for beginners to use as it is easy to apply and dries faster than other oils.

Thanks to its various components, Danish oil provides a protective barrier, a satiny finish and will not change color with age. This oil protects wood projects from scratches, damages by chemicals and heat, stains and is water resistant.

Surface Finishes

Shellac: this film forming, evaporative finish is a natural finish that can range in color from clear to rich red, though it may darken with age.

Both quick drying and easy to apply, shellac makes a great beginner finish for some projects. Shellac can easily be removed by alcohol and while not the most durable of finishes, it is easy to repair.

Varnish: a mixture consisting of resin, drying oil and a thinner, these wood finishes are considered as one of the best wood sealants available which is why it is often applied to floors, cabinets, and furniture.

Varnish is highly durable and offers UV protection, making it suitable for a variety of indoor and outdoor woodworking projects. While varnish has several benefits, its slow drying time makes it susceptible to dust and dirt before a piece is properly finished.

Lacquer: this high gloss finish has high durability and resistance to damage which is why its presence is notable in homes worldwide!

A combination of shellac dissolved in alcohol, lacquer dries to a very hard and smooth protective coating. There are various types of lacquer including:

Nitrocellulose Lacquer: the most common type of lacquer and commonly used for wood projects. Nitrocellulose lacquer provides a beautiful shine and hard protective coating but can yellow with age and crack with temperature changes.

Acrylic Lacquer: with a base of acrylic, this lacquers original intent was for cars and other automotives. It dries rapidly, does not yellow and is an ideal choice for light-colored wood projects.

Water-Based Lacquer: durable and scratch resistant, water-based lacquer is regularly used in kitchen refinishing.

Metal Lacquer: despite its name suggesting it is used for metal, metal lacquer can be applied to metal, wood, and ceramic, among other things. It has high durability, making it useful for projects that will reside indoor and outdoor.

Wax: wood wax, often made from beeswax, is a easy-to-apply natural wood finish. Application and reapplication of wax wood finish is easy with the assistance of a cloth or paint brush.

Reapplication may be necessary as wax wood finish offers less protection than other finishes and can buff away. Wood wax can be a great option to apply to cutting boards.

Polyurethane: formulated with resin, polyurethane is water resistant and durable. Available in satin, semi-gloss and high gloss, this clear finish enhances the natural appearance of the wood species without altering the color.

While it offers a durable coat, polyurethane finishes do not offer UV protection and therefor, should not be used on outdoor projects. When damaged, polyurethane finishes can be hard to repair.

Wood Dye: available as powders that can be mixed with water and alcohol, wood dye can provide deep and vibrant color while enhancing the natural appearance of your wood as it penetrates deep into your workpiece.

While it provides beautiful color, wood dye can be hard to apply for inexperienced users, leaving uneven color. Wood dye can also fade overtime and does not provide the protective layer that other wood finishes do.

Wood Stain: wood stain sits on top of the surface of a workpiece, providing both a durable, protective outer layer and beautiful color. Ideal for both indoor and outdoor furniture, wood stain is easier to apply than wood dye, though its dry time is longer.

Water-based finish: easy to use, with a quick dry time and a scuff resistant layer, water-based finishes can be an ideal choice for many projects.

While they are an environmentally friendly and non-fire hazardous, they come with disadvantages including raising wood grain, are hard to remove and have sensitivity to low temperatures and humidity.

Wood Paint: when you are looking for a pop of color, wood paint is the way to go. Easy application can be done through a brush, roller or spray and wood paints range in satin to high gloss.

An advantage of wood paint over other wood finishes is its ability to hide flaws on wood boards. Though wood paint can be a great option for adding color and concealing flaws, it tends to be an incredibly permanent option, with a high level of difficulty to remove.

Additionally, painted wood can result in peeling or bubbling that will regularly have to be maintained.

Wood Finishing Techniques

Hand-Sand the Curves

Sand curved surfaces—and other areas an electric sander can’t reach—by hand. Treat all areas equally, using the same progression of sandpaper grits for both hand and power sanding. Start with 80-grit to sand away blemishes, then use 120-grit and finally 180-grit.

Using these exact grits isn’t vital (100-150-180 works too), but it’s important to progress in steps, removing deeper scratches and leaving finer scratches each time.

Sand Without Scratches

A

random orbital sander
leaves scratches that are practically invisible, so you can sand across joints where grain changes direction. But move slowly (about 1 inch per second) and apply light pressure. Otherwise, you’ll get swirly scratches.

Test Stains Thoroughly

You can’t rely on those stain samples on display in stores. Actual color varies a lot, depending on the type of wood and how you prepared it for finishing. So save scraps from your project, run them through the same sanding process and use them to test finishes.

If you didn’t build the item you’re finishing, run tests on an inconspicuous area—the underside of a table, for example. Test stain on scraps to get the color you want.

Leaving excess stain on the wood for longer or shorter periods won’t affect the color much. If it’s a custom color you’re after, you can mix stains of the same brand.

Oil-based poly has an amber tone that can dramatically change the color of stained or unstained wood. Water-based polyurethane affects the color only slightly. The same stain was used on the samples shown in this photo.

Sand With the Grain

Sand with the grain when hand sanding or using a

belt sander. Scratches are hard to see when they run parallel to the grain. But even the lightest scratches across the grain are obvious, especially after staining.

Renew Woodwork Without Refinishing

If your stained and varnished woodwork is looking a little shabby, you can save time and money with this quick fix. You don’t have to strip the finish from your dingy woodwork. Just head to the store and pick up wood stain that’s a close match.

Start your renewal project by washing the woodwork with soapy water. Rinse with clear water, then gently scrape off any paint spatters with a plastic putty knife.

When the wood is dry, dip a rag into the stain and wipe it over the wood. Bare spots and scratches will pick up the stain.

Finish by wiping the woodwork with a clean cloth to remove the excess stain. After the stain dries for a few days, you can add a coat of furniture wax or wipe-on poly to really liven up the old wood.

Usually, a brush is the best tool for applying polyurethane. For water-based poly, a synthetic brush (such as nylon or polyester) is best. For oil-based poly, use a natural-bristle brush.

In either case, plan to spend more for a good-quality brush. Quality brushes hold more finish, lay it on smoothly and are less likely to leave lost bristles in your clear coat. If you clean your brush immediately after use, it’ll serve you well far into the future.

Leave Mistakes Alone (Usually)

When you notice a run, missed spot or other problem in the polyurethane you applied minutes earlier, you’ll be tempted to brush it out. Don’t. The finish may look wet, but chances are it’s already sticky, and brushing will only make a mess.

There are a couple of exceptions to this rule: You can pop tiny air bubbles with a pin, and you can pluck out a hair, a lost bristle or unfortunate fly using sharp tweezers and a steady hand.

Wipe Instead of Brush

Wipe oil-based polyurethane onto hard-to-brush surfaces using a soft, lint-free cloth. Wiping leaves a thinner coat than brushing, so you’ll have to apply more coats. Water-based poly becomes sticky too fast for wiping.

Use a Pad on Large Areas

Apply water-based polyurethane to large surfaces fast by using a paint pad. Water-based poly dries quickly and may not allow enough “wet” time for brushing out big areas.

Spray on the Final Coat

Here’s a trick for getting a glass-smooth finish on your next woodworking project. Start by brushing on a coat of gloss polyurethane. Let it dry overnight. Then lightly sand with 320-grit sandpaper to remove imperfections.

Use a tack cloth or vacuum cleaner and soft brush attachment to remove the dust. Repeat this process for the second coat.

Finish up by spraying on the final coat. You can buy aerosol cans of polyurethane in satin, semigloss and gloss finishes. Any of these can go over the gloss coats.

Brushing on the first two coats allows you to build up a thicker layer of finish with less cost and effort than spraying from cans. And using an aerosol can to apply the final coat produces a professional-looking finish, free of brush marks.