Varnish is a liquid or paste made from a resin and a solvent that’s applied to a surface and dried to form a hard film. It’s used to protect and beautify wood, metal, and many other materials.
In this guide, I’ll explain what a varnish is, how it works, and what it’s used for.
In this post we'll cover:
- What You Need to Know About Varnish
- The Colorful History of Varnish
- The Many Types of Varnish: Which One is Right for You?
- Applying Varnish: A Step-by-Step Guide
- The Not-So-Good Side of Varnish
- Varnish vs Polyurethane: Which is the Best Wood Finish?
What You Need to Know About Varnish
Varnish is a clear, transparent or tinted coating that is applied to wooden surfaces to enhance their appearance and provide protection against damage caused by wear and tear, UV rays, and other environmental factors. It is an essential tool for anyone working on a wooden project, whether it’s furniture, art pieces, or wooden surfaces facing general wear and tear.
The Importance of Choosing the Right Type of Varnish
Choosing the right type of varnish for your project can be a confusing decision. With so many different types and versions available, it’s important to know the difference between them to ensure you get the right one for your needs. Some of the main types of varnish include natural, synthetic, and resin varnishes, each with their own unique components and level of durability.
Applying Varnish Properly
Applying varnish involves a lot more than just brushing it onto the surface. To ensure that the varnish sets properly and provides the necessary protection, it’s important to follow the proper process. This may include sanding the surface, choosing the right brush, and applying multiple layers of varnish.
The Versatility of Varnish
One of the reasons varnish is so popular is its versatility. It can be used to create a variety of textures and colors, depending on the type of varnish and the materials used. In addition to enhancing the appearance of wooden surfaces, varnish can also be used as a topcoat for paintings and other artistic pieces, adding depth and richness to the colors.
The Benefits of Varnish over Polyurethane
While polyurethane is another popular coating for wooden surfaces, varnish has some unique benefits that set it apart. For example, varnish is usually harder and more protective than polyurethane, and it can be tinted to add color to the surface. Additionally, varnish is available in different languages, making it easier to find the right version for your needs.
Ensuring Proper Protection with Varnish
In addition to enhancing the appearance of wooden surfaces, varnish is an essential tool for ensuring proper protection against damage caused by wear and tear, UV rays, and other environmental factors. By choosing the right type of varnish and applying it properly, you can ensure that your wooden surfaces remain in good condition for a long time.
The Colorful History of Varnish
Varnishing is an ancient technique that dates back to ancient Egypt. Early varnishes were developed by mixing resin, such as pine pitch, with a solvent and applying them with a brush to achieve the desired effect. The use of varnish spread throughout the centuries, with painters and craftsmen using it to protect and enhance their work.
The Medieval Era and Beyond
In the late 14th century, Cennino Cennini, an Italian painter, wrote a manuscript that exhaustively covered the topic of varnishing. He described various options for varnishing, including using gum from the tree, glair, and even garlic and honey as additives. However, he also criticized the use of varnish, warning that it could yellow over time.
The Renaissance and Early Modern Period
In the 17th century, the Swiss physician and alchemist Theodor de Mayerne published a book on the art of painting, which included recipes for varnishes. He recommended using egg yolk and vinegar as a varnish for paintings. In the 18th century, the Scottish physician Alexander Carlyle gave instructions for reverse painting on glass using varnish.
The Late 19th and Early 20th Centuries
In the late 19th century, American painters Richard and Jennys Van Vleck gave instructions for using varnish in their book “The Practice of Painting and Drawing.” They recommended using varnish to protect paintings from dust and dirt. In the early 20th century, Vincent van Gogh used varnish in his paintings to achieve a glossy effect.
Today, varnish is still used by painters and craftsmen to protect and enhance their work. Modern varnishes are made with synthetic resins and solvents, and they come in a variety of finishes, from matte to high gloss. Varnish is also used in woodworking to protect and enhance the natural beauty of wood.
The Many Types of Varnish: Which One is Right for You?
When it comes to wood finishes, varnish is a popular choice due to its versatility and tough performance. But did you know that there are many different types of varnish available? Each one is designed to achieve a particular effect or improve a certain area of the wood’s appearance or protection. In this section, we’ll take a closer look at the various types of varnish and their unique features.
The Unique Features of Each Type of Varnish
Here are some of the unique features associated with each type of varnish:
- Oil-based varnish: This type of varnish is highly versatile and can be used on a wide range of materials. It is also excellent at protecting the wood from water and other elements. However, it can take a long time to dry properly and may require extended drying stages.
- Water-based varnish: This type of varnish is easier to clean up and less harmful to the environment. It dries faster than oil-based varnish and is less likely to yellow over time. However, it may not be as tough or durable as oil-based varnish and may require more coats to achieve the desired degree of protection.
- Polyurethane varnish: This type of varnish is highly versatile and can be used on a wide range of materials. It is tough, strong, and resistant to reacting to many different substances. It is available in different finishes, including matte, satin, and glossy. However, it can be difficult to remove once applied and may not be ideal for certain types of wood or finishes.
- Spar varnish: This type of varnish is specifically designed for outdoor use and is highly resistant to water and other elements. However, it may not be as versatile as other types of varnish and may not be suitable for indoor use.
- Musical instrument varnish: This type of varnish is highly thin and highly polished, allowing the natural grain of the wood to show through. It is also designed to improve the performance of the instrument by allowing the wood to vibrate freely. It is available in different finishes, including matte and glossy. However, it may not be suitable for other types of wood finishes and may require a little more energy to apply properly.
Applying Varnish: A Step-by-Step Guide
Before you start applying varnish to your wood project, you need to make sure the surface is properly prepared. Here’s what you need to do:
- Sand the surface with a fine grit sandpaper to remove any rough spots and create a smooth surface. Sanding also helps the varnish adhere better to the wood.
- Clean the surface with a rag and mineral spirits to remove any dust or debris. Make sure the surface is completely dry before moving on to the next step.
Choosing the Right Varnish
There are a variety of varnishes available, each with their own level of sheen and durability. Here are some things to consider when choosing the right varnish for your project:
- Traditional varnishes are made from natural oils and resins, while synthetic varnishes are made from synthetic materials. Synthetic varnishes are generally more durable and offer better protection against UV rays.
- Some varnishes require thinning before they can be applied, while others can be used straight out of the can. Read the label carefully to determine if your varnish needs to be thinned.
- If you want a superior finish, choose a custom or pure varnish. These varnishes are more expensive, but they offer a higher level of clarity and depth.
Mixing and Applying the Varnish
Now that you’ve chosen the right varnish, it’s time to start applying it to your wood project. Here’s how to do it:
- Stir the varnish thoroughly before you start. Stirring ensures that the mixture is fully blended and will result in a consistent finish.
- Pour the varnish into a clean container and fold a rag into a pad. Dip the pad into the varnish and gently wipe it onto the wood, working in the direction of the grain. Make sure to cover the entire area evenly.
- Allow the varnish to dry according to the manufacturer’s instructions. This can take anywhere from a few hours to overnight.
- Once the varnish is dry, sand the surface lightly with a fine grit sandpaper. This will help smooth out any rough spots and prepare the surface for the final coat.
- Apply a second coat of varnish using the same technique as before. Allow it to dry completely before moving on to the next step.
Now that you’ve applied the final coat of varnish, it’s time to add some final touches to your wood project. Here’s what you need to do:
- Sand the surface lightly with a fine grit sandpaper to remove any rough spots or drips.
- Clean the surface with a rag and mineral spirits to remove any dust or debris.
- Depending on the type of varnish you used, you may need to apply a special wax or polish to the surface to bring out the shine.
- Allow the surface to dry completely before using or handling your wood piece.
Remember, applying varnish can be a difficult process, but with the right techniques and preparation, you can achieve a perfect finish every time.
The Not-So-Good Side of Varnish
Varnish is a traditional protective covering for wooden surfaces, but not all types of varnishes are ideal for every project. Here are some types of varnish and their drawbacks:
- Oil-based varnishes: These varnishes are commonly used for interior wooden surfaces, but they tend to yellow over time and have a low density, which means multiple coats are required for a higher protective coating.
- Synthetic varnishes: These varnishes are easy to apply and dry faster than oil-based varnishes, but they contain solvents that produce bad effects on the body and the environment.
- Spirit varnishes: These varnishes are composed of a mixture of resin and alcohol and are ideal for musical instruments, but they are not suitable for outdoor projects since they are soluble in water and fire.
Beginners Find Varnish Difficult to Apply
Varnish is a special type of coating that needs a particular layout and technique to produce a fair and even finish. Beginners will find that varnish can be difficult to apply because:
- Varnish dries very slowly, which means it needs multiple coatings to achieve the desired effect.
- Varnish is thinner than other sealants, which means it needs more coats to produce a higher protective coating.
- Varnish needs a special type of thinners to improve its density and consistency.
Yellowing and Drying are Common Issues
One of the most common drawbacks of varnish is that it tends to yellow over time, especially when exposed to sunlight. Additionally, varnish dries very slowly, which means it needs more time to cure and harden. This can be a problem for wooden surfaces that need to be routinely repaired or previously varnished.
Alternative Protective Coatings
If varnish is not the ideal protective coating for your project, here are some alternatives:
- Lacquer: This is a resinous coating that dries faster than varnish and produces a hard and durable finish. It is commonly used for decorative paintings, paneling, and wooden floors.
- Oleo-resinous coatings: This is a mixture of oil and resin that produces a protective coating for wooden surfaces. It is commonly used for roof trusses and wooden surfaces exposed to fire.
- Mineral coatings: This is a water-based coating that produces a protective shield for wooden surfaces. It is commonly used for outdoor projects and wooden surfaces exposed to water.
Varnish vs Polyurethane: Which is the Best Wood Finish?
When it comes to choosing the best wood finish, varnish and polyurethane are two of the most popular products. While they may seem similar at first glance, there are some key differences to keep in mind:
- Varnish is a traditional finish made from resins, oils, and solvents, while polyurethane is a plastic resin.
- Varnish offers better protection against UV damage, making it an excellent choice for outdoor projects.
- Polyurethane dries faster and is easier to apply, making it a good option for quick projects.
Pros and Cons of Varnish
Varnish has been used as a wood finish for centuries, and for good reason. Here are some of the pros and cons of using varnish:
- Varnish creates a beautiful, natural finish that allows the wood grain to show through.
- It offers excellent protection against the elements, making it ideal for outdoor use.
- Varnish is versatile and can be used on a wide range of wood pieces, from furniture to decks.
- Varnish can be difficult to apply evenly, and achieving the desired thickness can be a challenge.
- Regular sanding and polishing are required to keep the finish looking fresh.
- Varnish can feel sticky or tacky to the touch, which some people find unpleasant.
Varnish is a transparent coating applied to a surface to improve its appearance and protect it from damage.
It’s a great tool for woodworkers (more essential ones here) and artists, and there’s a varnish for every project and every need. Just remember to choose the right type and apply it properly for the best results.
I'm Joost Nusselder, the founder of Tools Doctor, content marketer, and dad. I love trying out new equipment, and together with my team I've been creating in-depth blog articles since 2016 to help loyal readers with tools & crafting tips.