How To Seal Painted Wood For Outdoor Use? (Answered!)

Wood sealer is similar to sunscreen for painted wood projects. 

It protects the paint from fading and sun damage while repelling water, dirt, and mildew.

Learning how to seal painted wood for outdoor use is a simple process that will help your project last longer. 

We’ll show you how to seal a deck, mailbox, or patio furniture in just a few simple steps.

VIDEO: How To Seal Wood For Outdoor Use?

How to Seal Painted Wood for Use Outside (Step-by-Step Process)

To begin, select the appropriate sealant for sealing painted wood for outdoor use. Then, clean and lightly sand the wood to prepare it for sealing.        

Use a brush, roller, or sponge to apply a sealant to painted wood. Then, reapply the sealant and sand the wood. Before and after sealing, make sure your wood is completely dry.

Prepare your tools and materials before beginning the sealing process. They are listed below.

Sealing tools and materials for the painted wood

The following tools are required to set up your workspace as you prepare to seal painted wood.

• Eye protection and protective clothing
• tack cloth or fresh rags
• Sandpaper
• Paintbrush, roller, or sponge of high quality
• Sealant for the outdoors

How to Seal Painted Wood for Outdoor Use

Let’s go over the steps for sealing painted wood for outdoor use in greater detail.

Step 1: Select the appropriate sealant

The most crucial step in sealing painted wood is selecting the proper sealant.

The type of sealant you will use will be determined by the type of paint coat on the bare wood surface. Oil-based paint, for example, will naturally complement an oil-based sealant.

There are numerous wood sealants on the market, but we have narrowed it down to three.

Polyurethane

A polyurethane sealant is an excellent example of a sealant type. Polyurethane is a clear, long-lasting coating in oil- and water-based polyurethane.

Polyurethane derived from oilSolvent-based polyurethane is another name for oil-based polyurethane.

This polyurethane sealant has a higher percentage of Volatile Organic Compounds (VOCs) than water-based sealants, making it more durable.

Another advantage of oil-based polyurethane is its low cost. It also has a glossier appearance but may darken and turn yellow over time.

However, one primary reason you should avoid using oil-based polyurethane is its long curing time due to the high concentration of VOCs.

Because these VOCs harm the body, sufficient time must be allowed for the toxic fumes to be released.

Polyurethane based on water.

Though both types of polyurethane emit an odor, water-based polyurethane is less smelly due to a lower percentage of VOCs.

Moreover, the lower concentration of VOCs in water-based polyurethane makes it less harmful to humans and, as a result, requires less time to dry completely.

Finally, water-based polyurethane maintains its clarity over time and is suitable for acrylic and latex-painted finishes.

Remember that a clear polyurethane topcoat not only seals exterior paints, extending their life but also gives painted wood a gleaming appearance.

Polycrylic

A polyacrylic sealant is similar to a water-based polyurethane. Polycrylic contains polyurethane resins, which protect the painted wood from sunlight, moisture, and extreme weather.

It is clear, less odorous, and contains a low percentage of VOCs, making it less toxic. It is also ideal for use with flat latex paint and is very simple to clean. Polycrylic can produce a variety of paint finishes, including clear, satin, and high gloss.

Polycrylic, on the other hand, is not as long-lasting as polyurethane. Another disadvantage is that it will not bond with oil-based paints; because Polycrylic is water-based, adhesion issues are likely.

Paint Sealer Combinations

Sealer combos are new products that have recently appeared on the market. Sealer combos are a novel blend of paint and sealant in a can. Furthermore, these products do not require any additional coats.

They also do not stain because they have a clear coat and are less prone to discoloration; thus, they are appropriate for painting and sealing white furniture or light-colored outdoor wood.

Furthermore, sealer combos come with specific preparation and application instructions from the manufacturer, so read and follow these before use.

Epoxy

Another excellent example of a wood sealant is epoxy. Because of its complex, protective film, epoxy provides a long-lasting finish for outdoor furniture. This non-porous and, thus, extremely water-repellent coating can last for 5-10 years.

Boatbuilders use epoxy for this purpose. Epoxy coatings are available in two varieties: clear and colored. Epoxy can also be used in conjunction with an exterior varnish.

The rugged, protective covering is provided by epoxy, and the exterior varnish protects against UV rays from the sun. However, one significant disadvantage is the high cost of Epoxy.

Exterior Lubricants

To seal the wood, naturally occurring oils can be used. Popular oils include linseed, tung, coconut, and walnut oil.

However, in recent years, companies have produced various blends of these oils. Linseed and tung oil, mineral spirits, and other ingredients are commonly used to create products with improved wood sealing activity.

Danish oil, a blended product, imparts a lustrous or glossy appearance. Teak oil, which has a slight sheen and is more durable, is another example of a blended product.

Step 2: Scrub-painted wood.

Before sealing painted wood, ensure the surface is clean, free of dust, dirt, or grime, and dry.

Unremoved dirt, oil, or other heavy residues on the wood will prevent the clear polyurethane or polyacrylic sealants from adhering to the paint. Use one-half cup of trisodium phosphate (TSP) mixed with warm water for this cleaning.

Wipe the wood with a rag soaked in the TSP solution while wearing rubber or latex gloves. However, take care not to soak the painted wood’s surface.

Step 3: Get the sealant ready.

Before applying the sealant, it must be prepared. To do so, thoroughly combine the binders and pigment with a long, clean stick. To avoid separation, make sure all of the components are thoroughly mixed. Stir gently as well to avoid bubbles.

Manufacturer’s instructions for use are usually included with sealer combos. To ensure a smooth sealing process, carefully read the instructions.

Step 4: Lightly sand and clean the painted wood.

To begin, put on safety goggles to protect your eyes from sawdust. Next, lightly sand all rough spots on the painted wood surface with 220-320 grit sandpaper. However, the surface must be dry.

After sanding, use a tack cloth to clean the wood surface.

Step 5: Seal the painted wood.

To avoid the formation of bubbles, dip the brush into the can of sealant and do not wipe off excess sealant on the can’s edge.

Paint in a single direction and evenly apply the wood sealant from edge to edge and in the direction of the wood grain. This technique makes your paint look more natural and prevents bubbles from forming.

It is important to note that it is preferable to paint forward rather than backward. If bubbles or drips appear, smooth them out with a paintbrush while the coat is still wet.

Allow the wood sealant to dry per the manufacturer’s directions. Also, don’t brush too hard, as this can cause air bubbles, which can ruin your finish. Furthermore, over-brushing makes your brush sticky.

Step 6: Lightly sand and reapply the sealant.

Sand lightly once more, then clean the wood surface with a clean rag or tack cloth to remove all sawdust and residues.

The sealant should then be reapplied.

Additional coats of polyacrylic or polyurethane wood sealant can be applied up to three times. To avoid stickiness, sand between coats and let the wood dry before recoating.

Step 7: Allow the wood to dry.

Allow the wood to dry after applying the final coat and sealing it.

Allow for proper drying or curing before using the finished piece, either overnight or according to the manufacturer’s instructions.

Why Use Exterior Paints to Seal Wood for Outdoor Use?

Exterior paint, while extremely useful, is only sometimes adequate protection against the extreme weather conditions that outdoor furniture faces.

Sunlight’s UV rays can cause damage to outdoor furniture. Photodegradation occurs when the pigments on the painted wood absorb UV rays, causing the bonds that hold the paint together to break down.

Fading is caused by the breakdown of the bonds in paint. The fading of paint on wood causes it to lose its attractive appearance, which is bad enough, but things can worsen.

When wood loses its paint and water, another destructive agent can enter. Water can weaken wood on its own. Furthermore, water in wood promotes the growth of fungi, which can cause additional damage to the wood.

Alternatively, instead of painting your wood, you can powder coat it. Powder-coating is a more durable, weather-resistant option than paint, and it protects your wood better.

When Should You Paint and Seal Unfinished Wood Surfaces?

To begin, determine the moisture content of the exterior wood. Usually, a moisture content of 15-20% is considered acceptable; anything higher will result in a loss of adhesion between the wood and the thin coat of paint applied.

After removing all dried-up and oozing sap, use a suitable primer to seal off all knots and affected sap areas. Finally, fill in all the cracks and holes with a high-quality filler before sanding the wood with sandpaper.

For a smooth finish of wood stain, sand in the same direction as the wood grain, then clean off the sawdust. Your wood is now ready for painting and sealing.

Conclusion

Exterior paint alone is not always sufficient to protect outdoor wood furniture from the damaging effects of sunlight, water, and extreme weather.

Sealing painted wood for outdoor use adds an extra layer of protection. Wood sealants used in sealing can protect and improve the appearance of painted wood. They are also long-lasting and inexpensive.

While working, wear protective equipment such as safety goggles, gloves, and a mask. Also, work in a well-ventilated area, preferably an open space like your yard. Have a good time.

FAQ on How To Seal Painted WoodFor Outdoor Use

Which type of sealer is ideal for protecting painted wood from the elements?

Polyurethane. Sealing outdoor paints with a clear polyurethane coating can help the finish last longer and protect it from the elements. This particular sealer is quite similar to polycrylic, with the exception that it can be purchased in two different formulations. Polyurethane with a water-based solvent is compatible with painted finishes made of latex and acrylic.

What kind of a finish do you put on painted wood?

Because they result in a more durable layer, polyurethanes that are based on solvents are the superior choice for sealing wood. When working with oil-based paints, this product is a wonderful option to have on hand.

What is the best clear varnish to use on painted wood that will be exposed to the elements?

The Varathane Water-Based Polyurethane in the Satin finish is widely regarded as the best clear coat for painted wood furniture. After putting seven different products through rigorous testing, the Water-Based Polyurethane offered by Varathane emerged as the undisputed victor! This clear coat works wonderfully for interior products such as furniture, cabinets, trim, and any other pieces of wood you might have lying around.

What kind of finish can you put on painted wood to protect it?

It is necessary to use paint sealers as a top coat in order to protect the paint. When it dries, a sealer leaves behind a finish that is tougher and more long-lasting than paint does. After just one or two coats have dried, the paint will be protected and able to withstand normal use. As a result of the fact that they prevent moisture from penetrating the paint, sealers make painted surfaces much simpler to clean.

Does painting wood make it more resistant to the elements?

Paint has the ability to successfully waterproof wood if it is properly maintained so that it can seal the wood and protect it from water. However, if the paint begins to break, water will be able to get through to the wood, and the wood will no longer be waterproof.