Best Varnish for Wood-How to Varnish Wood

Last Updated on August 19, 2023 by Ernest Godia

The best varnish for wood will keep your wood pieces looking pristine for longer and protect them from swelling, shrinking, and other forms of water damage. Varnishes also offer superior UV resistance, preventing fading and discoloration. 

Exterior-grade varnish can go a long way in protecting garden furniture and other wood items against insects and bugs, and premature deterioration. 

This guide reviews the best varnish for wood to help you select the most suitable option for your project. 

But first things first, here is a look at the different types of wood varnish available on the market.

Types of Wood Varnish

Many different types of wood varnish are available for different projects. Below are the main types of wood varnish:

Spirit Varnish

This type of varnish, also referred to as French polish, uses spirit as the solvent. 

Shellac is combined with spirit, and the final product is applied as a thin coat. This forms a translucent finish that shows the wood grains.

This varnish is only suitable for interior use since it lacks weatherproofing properties. 

Oil-Based Varnish

These varnishes use oil as a solvent. They take a lot of time to dry but form highly durable coats.

Use them on exposed surfaces that require regular cleaning or polishing and superior varnishing properties.

Water-Based Varnish

Also known as acrylic, these varnishes use water as a solvent. They are non-toxic and resistant to the sun’s ultraviolet rays, thus suitable for interior and exterior use.

Water-based varnishes come in gloss, semi-gloss, satin, and matte sheen levels. After application, they form a clear coat that remains clear over time. They are easy to clean away with soap and water, making them user-friendly.

Exterior Varnish

As their name suggests, these varnishes are used on exterior wood surfaces exposed to the weather.

They have superior UV resistance and include a fungicide in their formula to prevent termites and fungi growth.

Though exterior varnishes dry to the touch faster, it takes them time to cure.

Polyurethane Varnish

This type of varnish forms a clear, hard, and heat-resistant coat when applied to wood surfaces. This property makes it the best varnish for wood flooring, though it can also be used on other wood surfaces.

Polyurethane varnishes do not penetrate the wood well. For that reason, they require priming with a thin shellac solution or oil-based varnish.

Also, they are not the best option for exterior wood since they are not sufficiently resistant to UV rays. If you must use polyurethane varnish on exterior wood, look for one with added UV blockers.

Alkyd Varnish

This type of varnish is suitable for both interior and exterior wood.

Use this varnish to protect the wood against moisture, temperature changes, and UV damage. It can also help enhance the wood grain or colors on the wood.

Marine Varnish

Also known as yacht varnish, this varnish is designed mainly for use on boats. The varnish is highly flexible to prevent cracks that may allow water to penetrate.

Compared to the other varnishes, this varnish has less gloss.

Reviews of the Best Varnish for Wood  

Below are the six best varnish products for wood:

1. Totalboat Marine Spar Varnish – Best overall wood varnish

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Totalboat Marine Spar Varnish is designed mainly for wooden surfaces exposed to harmful chemicals and salty seawater. However, it can still do an excellent job on other wooden surfaces.

The varnish is easy to apply on all types of exterior and interior woods using a roller or brush in various temperatures. It dries fast, allowing you to apply multiple coats in a day.

Besides drying rapidly, the product leaves a uniform, highly durable coat on the wood.

With many sheen options, you can go for a high gloss finish or a satin one, depending on your preferences and wood surface needs. 

Apply 4 to 6 coats of the gleam gloss to get a high gloss finish. On the other hand, if you want a sleek satin finish, apply several layers of gleam gloss and use gleam satin for the final layer.

Pros

• Self-leveling formula
• Suitable for all types of exterior and interior woods
• Highly durable; it is resistant to UV light and remains flexible even after curing, ensuring that it will not crack or pill even in extreme temperature changes
• Easy to apply
• It can be used in a wide range of temperatures
• Available in two finish types
• Excellent coverage of 360 to 400 sq ft per gallon

Cons

• Requires multiple coats to get the desired results
• It is costly compared to other varnishes

2. MCCLOSKEY Voc Mow Spar – Most durable wood varnish

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MCCLOSKEY Voc Mow Spar is a premium product that offers optimal UV rays, water, salt spray, and chemical resistance. It is also highly flexible even after curing; thus, it can easily absorb impact damage or contract and expand with temperature changes to avoid cracking.

These features make this item the best varnish for wood doors, wooden shutters, windowsills and frames, outdoor furniture, and boat trim.

However, this varnish is not without limitations. It contains high levels of volatile organic compounds, making it harmful to use without respiratory protection. It is also highly flammable and produces an unpleasant odor.

Pros

• Highly durable
• Highly resistant to water, chemicals, salt spray, and UV rays
• Suitable for use on moving wooden parts such as doors because it is highly flexible to absorb impacts
• It can be used on both indoor and outdoor wooden surfaces
• Beautifies and protects the wood

Cons

• It is costly
• It is toxic, flammable, and produces a foul smell

3. System Three Clear Marine Spar Urethane Varnish – Most affordable wood varnish

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System Three Clear Marine Spar Urethane Varnish Coating is the most budget-friendly item on our list. However, this does not mean it lacks some features and advantages you would expect in a quality wood varnish.

First, this product has advanced UV blockers for enhanced UV protection. It does an excellent job protecting the wood from fading and maintaining the exterior wood’s beauty even with constant exposure to sunlight.

The product is resistant to various cleansers and chemicals and performs excellently against marring and scratching. 

In contrast to other varnishes, this product is designed to dry over a wide range of epoxy resin systems, including marine epoxy. You may varnish spray almost anything with the proper safety measures and techniques and get a glossy wood finish.

Pros

• The best option for those working on a tight budget
• Offers protection to boats, doors, outdoor furniture, and any other wooden surfaces that needs a clear, long-lasting gloss finish
• Highly durable
• It comes in satin and gloss finish
• You can apply it over epoxy
• No sanding is required before applying it

Cons

• Poor coverage
• Highly toxic and flammable

4. Rust-Oleum 207008 Marine Spar Varnish – Best Clear Varnish for Wood

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Your search is over if you’re looking for the clearest varnish for wood. The Rust-Oleum 207008 Marine Spar Varnish is a crystal-clear varnish that offers a lovely gloss finish. It is perfect for all interior and exterior wooden surfaces above ground or water, such as trim and railings.

Thanks to its flexibility, this varnish can absorb impact damage and contracts and expands when exposed to extreme temperature changes. 

It boasts great coverage. It can cover up to 150 square feet, and dries to the touch in only two hours.

Its tough coating offers outstanding UV, mildew, and salt resistance.

The downside of using this product is that it is highly flammable and smells bad. The sale of this varnish is restricted in Catalina Island.

Pros

• Crystal clear varnish that offers a lovely gloss finish
• Suitable for interior and exterior woods
• Protects against UV rays, salt, and mildew
• Durable; can absorb impact damage and expand or contract with changes in temperature.
• Excellent coverage

Cons

• It has a strong odor
• Highly flammable

5. Epifanes Clear Varnish – Best varnish for wood furniture

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If you wish to enhance the appearance of your new or old wooden furniture, Epifanes Clear Varnish is your best bet. This varnish is formulated with phenolic, alkyd resins, and tung oil, resulting in excellent flow, durability, and gloss. 

Additionally, it requires little maintenance. Since the coat formed after applying this varnish is very sturdy, you will not need to reapply it often. This helps you save money and labor in the long run. 

The product dries in 12 hours when applied at 65 degrees Fahrenheit and can be recoated in 24 hours.

Thanks to its superior versatility, you can use this varnish in many interior and exterior applications, marine or household, sprayed, rolled, or brushed.

Despite this varnish’s excellent performance, some buyers have pointed out that its packaging could be better.

Pros

• Suitable for new and old wood
• Easy to maintain
• It offers exceptional protection against  UV rays, water, and mildew
• Highly durable; it resists damage from UV rays
• Suitable for both household and marine use on exterior or interior wood

Cons

• Poor packaging

6. TotalBoat Halcyon Marine Varnish – Fast-drying wood varnish

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If you have limited time to complete your varnishing task, you will want to buy a fast-drying product designed to let you finish the job sooner. One such product is the TotalBoat Halcyon Marine Varnish. It dries fast, enabling you to apply up to 5 coats within a day.

The formula is in such a way that it offers the highest level of protection against weather-related damage. This varnish shields the wood against moisture-related damage and discoloration from the sun’s UV rays. 

It also boasts superior scratch resistance, keeping surfaces looking smoother and scratch-free for longer.  

You should be glad to know the varnish is easy to use, making it ideal for beginners. It is self-leveling, and you may apply it using various tools, including a foam brush, roller, or paint sprayer.

The product is formulated for both interior and outdoor use. Its gloss finish is available in amber and clear colors, while its satin finish is only in clear colors.

Pros

• Fast drying thus allows multiple coats in a day
• Highly durable due to its excellent adhesion and flexibility
• Self-leveling varnish
• Easy to use
• Excellent coverage of 80 to 100 sq ft per quart

Cons

• Poor packaging that might cause the item to damage during transit

How to Choose the Best Varnish for Wood

Below are a few factors you should consider when choosing the best varnish for wood:

Varnish Type

The first and most important consideration is the type of varnish you want to buy. 

Different types of varnish are available, as already discussed in this article. The best one will depend on your specific project. Do you wish to varnish interior or exterior wood, household or marine wood, softwood, or hardwood?

When buying wood varnish, we suggest you read the details on the package carefully. Most manufacturers indicate the project that the product is most suitable for. This information should help you choose the suitable type for your project.

Ease of Application

If it is your first time to varnish wood, it is best to go for a product that is easy to use.

The light varnishes are easy to apply even for beginners, compared to the thick ones that require professional application.

Drying Time

If you use wood varnish professionally, this is a factor that you must consider.

A fast-drying varnish enables you to apply more coats in less time. This, in turn, saves you some valuable time that you can put into other tasks, allowing you to complete more projects sooner and serve more clients on time. 

Durability

Durability is one of the key factors that determine if a product can be deemed to be good. A varnish is not good if it doesn’t hold up well against the elements or starts to chip or crack sooner than desired.

A less durable finish means having to occasionally make repairs, recoats, and touch-ups. Therefore, consider researching well and choosing a product offering superior damage resistance and longer service life. 

Durable varnishes allow you to avoid unnecessary costs and wasted time.

Protection level

When buying a varnish, there are a few protective qualities you must always look for:

• Water resistance: This is important if your wood is exposed to moisture, as moisture can cause the wood to rot quickly.
• UV resistance: All exterior varnishes should have this protective quality since UV rays can cause wood to break, crack, or fade.
• Mold resistance: Mold can affect the visual appeal of wood and even cause it to rot. Thus it is vital to ensure the varnish you buy is mold-resistant.
• Protection against impact damage: some woods, such as those used to make floors, are exposed to heavy use. When selecting a varnish for this wood, always choose the one that forms the hardest coat to offer resilience against heavy use.

Aesthetics

We use varnish mainly for its aesthetic qualities, so consider what the finished product will look like. 

Some varnishes will help enhance the natural appearance of your wood, while others will alter it. Also, you can choose between a high-sheen finish or a satin finish

How to Apply Varnish on Wood

Materials Required

Below are the materials you will require to varnish wood:

• Varnish
• Vacuum
• Varnish remover
• Coarse-grit and fine sandpaper
• Clean rags 

Procedure for applying varnish to wood

Below are the easy steps to follow when varnishing wood:

Step 1: Clean the wood surface

To ensure you are working on a clean, dust-free wood surface, start by vacuuming the wood surface to remove any dust and debris. 

Step 2: Strip down any old varnish or paint

It is advisable to remove the old varnish or paint on the wood surface before refinishing it with a fresh coat of wood varnish. This step helps ensure better results.  

Step 3: Sand the wood 

Once the old finish is gone, use coarse-grit sandpaper to knock down any surface bumps and then switch to fine-grit sandpaper for the final sanding. Working with a smooth wood surface is essential as it directly affects the results.

Step 4: Clean the surface

After sanding, clean the wooden surface using a damp cloth or tack cloth and let it dry. You can also use a vacuum to remove the sanding dust before wiping away the remaining wood dust with a tack cloth. 

Once the wood is clean, feel it with your hands to see if it needs further sanding before applying the varnish. 

Step 5: Apply the first coat of varnish

Use the recommended applicator to lay the first coat of varnish in the direction of the wood grain. 

Allow the varnish to dry according to the manufacturer’s recommendation, and then sand it lightly with fine sandpaper to scuff and prepare it for a recoat.

You can thin the initial coat to act as a sealer if you’re using a thick type of wood varnish. Newer water-based alternatives, however, are already thin.

Step 6: Apply subsequent coats of varnish

Apply the coats required to achieve the desired results, allowing for the recommended drying time between coats. 

In most instances, two to four coats are enough. However, there is no harm in applying more coats when using a thin type of varnish for better protection and increased durability.

In between the coats, ensure you do the sanding to promote better adhesion. However, do not sand the final coat.

What Ingredients are Used in Varnish

Many varnishes have three main ingredients. These ingredients are mixed in varying ratios and determine how well the varnish absorbs into the wood, dries, and protects the wood.

Oils

The oil content of a varnish largely influences how easily it will penetrate the wood. 

Varnishes with little to no oil in their formula hardly penetrate the wood grain and dry off rapidly as a result. Oil-based varnishes feature a greater oil ratio, absorb into the wood deeply, and dry slowly.

Tung oil and linseed oil are the two oils that are most frequently used as bases in varnish. They occasionally result in minor discoloration and typically turn the appearance of natural wood to a bit dark.

Resin

Resins can either be organic or synthetic.

A good example of organic resin is tree resin produced by trees to repair their damaged hard exterior surfaces and stop further deterioration. Another example is resins produced by insects such as lac bug.

Synthetic compounds are made of polymers and other plastics.

The kind of resin and its proportion in a varnish define the coating’s level of protection. A varnish with high resin quantity creates a durable coat on the surface that prevents physical damage. 

On the other hand, a varnish with a lower resin concentration can penetrate the wood and produce a waterproof seal.

The kind and quantity of resin used to manufacture a varnish also determines its impact on the wood color. Organic resins tend to discolor wood more compared to synthetic resins.

Solvent

A varnish also includes solvents, often known as thinners. 

Any combination of resin and oil will be too thick for easy application. The solvent, which might be anything from alcohol to water, helps dilute the combination,. 

Therefore, varnish with a high solvent-to-resin and oil ratio will be less effective and protective but easier to brush on. Once applied, the solvent evaporates, leaving the resin and oil to protect the surface.

Varnish Hardening Properties 

A varnish can dry in two main ways, as explained below:

1. Rapid Hardening

This hardening occurs when the solvent’s presence influences the liquid characteristics of the resin and oil. 

The thinner makes it easy to apply the varnish, but it quickly evaporates when exposed to air. The remaining portion of resin and oil hardens quickly, leaving the varnished surface dry and only partially protected.

2. Slow hardening

The oil and resins interact even after the thinner evaporates in slow-hardening varnishes.  The two ingredients slowly absorb into the wood and harden. The process may take several days, but the result is frequently a highly watertight protective covering.

Best Varnish for Wood: FAQs

What type of varnish is best?

Polyurethane varnish is the most preferred type of varnish. This type of varnish forms a clear, hard, and heat-resistant coat when applied to wood surfaces. However, it has poor wood penetration and is not the most suitable for exterior use.

What is the best waterproof varnish for wood?

Polyurethane varnish has the best waterproofing capabilities compared to other types of varnishes. For that reason, you can use it to varnish wood exposed to moisture.

How long does varnish last on wood?

Gloss polyurethane and oil-based varnish can last ten to twenty years. Satin finishes, however, have a shorter lifespan.

Does varnish darken wood?

Varnish forms a clear coat that protects the wood. It typically does not interfere with the color of the wood, although some oil-based varnishes may make the natural appearance a little dark.

How many layers of varnish on wood?

Two to three layers are usually enough when varnishing wood. However, there are no negative effects in applying even more layers, and it can result in a more protective and desirable finish.

What is the best for wood; varnish or oil?

Varnish is better for wood compared to oil. This is because varnish is more resistant to heat, water, mildew, mold, and chemicals than oil. It also forms a tough coat that resists scratches and dents. 

Does varnish need a primer?

Varnish does not need a primer. However, using a primer on large surfaces like wooden floors can be cost-effective. Priming allows you to use fewer coats of varnish, which can mean saving on the total cost of varnish for your project.

Best Varnish for Wood: Final Take 

Varnish can enhance the appearance of your new wood or restore that of the old wood. The best varnish for wood can also protect the wood from the damaging effects of water, UV rays, mold, and mildew.

But choosing the best varnish for wood can be challenging due to the sheer number of options on the market. 

This guide reviews six varnishes for wood that you may use on your project. We hope the information is helpful and will make your next varnishing job easy.