Wood sealers are protective coatings that protect wooden surfaces from moisture, water, and other elements.
They create a moisture-resistant layer over the surface that prevents water from penetrating and damaging the underlying surface.
Different wood sealer types include polyurethane, lacquer, wax, varnish, and shellac.
What are Wood Sealers?
Wood sealers are protective topcoats that protect wooden surfaces from moisture, water, scratches, stains, and weather elements. They create a moisture-resistant layer (or barrier) over the surface that prevents water penetration.
Most wood sealer finishes are transparent and high-gloss, meaning they don’t change the existing surface color shade. But, tinted wood sealers are also available.
Wood sealers are topical finishes, meaning they don’t penetrate the surface pores to adhere, they create a layer (or barrier) over the surface.
The wood sealer qualities include the following.
- Water repellency.
- UV protection.
- Mold Resistance.
- Transparent or Tinted Finish.
- Enhanced Durability.
- Different sheen finishes.
Read More: How To Seal Wood For Outdoor Wood?
Different Wood Sealer Types
Different wood sealer types are listed below.
- Polyurethane Sealer
1. Polyurethane Sealer
Polyurethane sealer is a protective finish that creates a glossy moisture-resistant layer (barrier) and protects wooden surfaces from moisture, water, scratches, and weather elements.
There are two polyurethane types; water-based and oil-based polyurethane. Water-based polyurethane has a faster drying time and retains its clear finish longer, while oil-based polyurethane creates a more durable finish.
Polyurethane is a synthetic plastic in liquid form. It is made through a chemical reaction between a base (polyols) and hardener (isocyanate compounds).
You can use water-based polyurethane for interior wooden surfaces, and oil-based or exterior polyurethane for exterior surfaces. Exterior polyurethane has extra additives that make its finish UV-resistant.
The polyurethane advantages are listed below.
- Water-resistant and can protect wooden surfaces from water damage.
- Exterior-grade polyurethane is reinforced with UV-blocking additives.
- Easy to apply – You can brush or spray on poly.
- Weather-resistant. It protects wood from warping, corrosion, and weathering.
- It is available in different finishes from satin to high gloss.
- Flexible finish and can withstand temperature changes without cracking or peeling.
- You can mix it with different paints to get a colorful durable finish.
Polyurethane disadvantages are listed below.
- Oil-based polyurethane is known to yellow over time due to the presence of synthetic oils in its formula.
Lacquer is a clear or colored protective finish that creates a hard and strong layer over the wood surfaces to protect them from moisture, water, and scratches.
It’s known for its fast dry time, smooth and clear finish, ease of re-coating, and versatility.
You can use lacquer for interior and low-traffic exterior surfaces to protect them. While lacquer has a durable and moisture-resistant finish, its finish doesn’t have the same protective level as polyurethane.
Lacquer sealer advantages are listed below.
- Easy to apply.
- Fast dry time.
- Tough and durable finish.
- Protects interior surfaces from water and moisture.
Lacquer sealer disadvantages are listed below.
- Its finish tends to discolor gradually.
Wax is a paste-like natural protective finish that enhances the wood’s appearance and protects it from water, moisture, and scratches.
It creates a rich and glossy sheen that enhances the wood’s natural appearance by highlighting the surface texture and patterns. Wax has a long dry and cure time due to its thickness and formula.
Traditionally, wax is made by mixing beeswax with oil, usually a plant-based oil like walnut oil, linseed oil, coconut oil, or olive oil. The combination produces a thick paste-like gel that can be massaged directly on wooden surfaces.
You can use wax sealer for interior wooden surfaces to protect them from small water and moisture amounts. Wax sealer isn’t durable and moisture-resistant enough to protect exterior surfaces.
Wax sealer advantages are listed below.
- Enhances the wood’s appearance by creating a high-gloss finish that highlights surface patterns and texture.
- Protects surfaces from small water amounts.
- Reflective finish.
Wax sealer disadvantages are listed below.
- Long dry time.
- Not durable enough to protect exterior surfaces.
- You need to hand-polish it which can be time-consuming, especially on large surfaces like floors.
- Hard to remove from surfaces.
Varnish is a protective coating applied over different surfaces (usually wood) to protect them from moisture, UV rays, water, and scratches. It creates a glossy or satin finish that enhances the surface appearance by revealing its texture and patterns.
There are different varnish types and each has different feature qualities. For instance, spar varnish is used on sea vessels and high-moisture areas because it has good water resistance.
Exterior-grade varnish is used on outdoor furniture and building exteriors because it is weather-resistant and doesn’t degrade when exposed to UV rays.
Alkyd varnish is a versatile finish that has been altered with vegetable oils to make it dry faster and give it a clear finish. Other types include spirit, oil, and acrylic varnish.
The varnish formula depends on the brand, type, or manufacturer. But, the main ingredient of all types include resins, usually alkyd resins, and a solvent or carrier, usually an oil-based solvent.
It’s also common for varnish to contain dye or pigments. This is often done to give the finish color when it dries. Since the product is oil-based, it takes a while to dry because the solvent (or oil) needs to evaporate first.
You can use varnish for interior and exterior surfaces since it has impressive water-resistant qualities.
Varnish advantages are listed below.
- Durable and it offers excellent wood protection.
- Water-resistant and commonly used on surfaces that are exposed to moisture to protect them from water damage.
- Flexible and can withstand changes in temperature without cracking or splitting.
- Great for outdoor use because it is UV-resistant.
- It has a honey tone that enhances the texture and finish of your wooden surface.
- It can be used on finished wood since it doesn’t penetrate wood grain.
Varnish disadvantages are listed below.
- Long dry time.
- Hard to Apply.
Shellac is a wood shellac that uses shellac as its main ingredient. Shellac is a natural resin obtained from the lac bug (“Kerria lacca”) that is harvested, processed, and mixed with alcohol to create the shellac sealer.
The shellac sealer is known for its thin viscosity, fast dry time, natural formula, clear and transparent finish, and good adhesion.
You can use shellac over interior low-traffic surfaces exposed to low water amounts or usage. Shellac doesn’t have good protective qualities when compared to other sealers, such as polyurethane.
Once shellac is applied, the alcohol evaporates from the coating and leaves a thin protective layer over the surface.
The shellac advantages are listed below.
- Fast dry time.
- Natural Formula.
- Blend well with different color and paint types.
- You can use it as basecoat before applying another wood sealer.
- Doesn’t yellow over time.
The shellac disadvantages are listed below.
- Low durability and protective levels compared to other sealers.
- Not durable enough for exterior surfaces.