Unlocking the Beauty of Wood: How to Varnish Wood Perfectly

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As an experienced woodworker, I appreciate the art of varnishing wood. It’s a crucial step in woodworking that enhances the natural beauty of the wood and protects it from the wear and tear of daily life. 

In this guide, I will take you through the step-by-step process of varnishing wood, sharing my expertise and tips to help you achieve a smooth and lustrous finish every time. So, let’s dive into wood varnishing, where precision meets craftsmanship.

The Importance of Varnishing Wood

When it comes to woodworking, Varnishing wood is more than a routine task; it’s an art form. It’s applying a protective and decorative finish to wood surfaces, enhancing their natural beauty while safeguarding them from the ravages of time and wear.

sponge brush and Rust-Oleum 207008 Marine Spar Varnish

Whether working on a fine piece of furniture, restoring an antique, or finishing a wooden floor, the varnishing process is the key to a stunning, enduring result. Just imagine your wooden furniture, floors, or crafted pieces with a glossy sheen that invites admiration and envy.

Tools and Materials: What You Need

Before we delve into the varnishing process, ensure you have the right tools and materials. Here’s a list of what you’ll need:


The heart of the process. Select a high-quality varnish that suits your project. Consider the type of wood, its intended use, and your desired finish. Various varnish types are available, including polyurethane, water-based, oil-based, and more.

Natural-Bristle Paintbrush

Choose a brush with natural bristles, ideally made of hog hair or similar materials. Natural bristle brushes are well-suited for applying oil-based varnishes, as they hold and release them effectively.

paint brush

Paint Stirrer

An essential tool for thoroughly mixing the varnish. Make sure it’s clean and free of any contaminants.

Paint Mixing Cup

Use a dedicated container for mixing your varnish. Clear measuring cups with volume markings are ideal for precise measurements.

Paint Thinner

This is used for thinning the varnish if necessary. The choice of thinner depends on the type of varnish you’re using. For oil-based varnishes, mineral spirits or turpentine are common choices. Water-based varnishes may require water as a thinner.

paint thinner and mineral spirits

Respirator Mask

Your safety is paramount. Protect yourself from fumes and vapors by wearing a quality respirator mask. Ensure it’s suitable for use with the specific varnish and thinner you’re working with.

Preparing Wood for Varnishing

Before diving into varnishing, preparing the wood properly is essential. Let’s review the crucial steps to ensure your wood is ready for a flawless finish.

Choosing the Right Working Space and Varnish

Select a well-lit and well-ventilated workspace. Adequate lighting helps spot imperfections like air bubbles, brushstrokes, and dents, while proper ventilation is essential to avoid discomfort from fumes. 

preparing work area

Keep the space clean and dust-free to prevent particles from settling on your work during varnishing. Pay attention to temperature and humidity, aiming for 70°F to 80°F (about 21°C to 26°C), and wear protective gear to safeguard your health.

Removing Old Finishes

Consider whether you need to remove old finishes from your wood. You can apply varnish over an existing surface or remove old finishes using methods like paint stripper, sanding, or paint thinner, depending on your project’s requirements.

Sanding the Wood

Sanding is a crucial step in achieving a smooth finish. Use medium to fine-grit sandpaper [1] to remove imperfections and create a surface that allows varnish to adhere properly.

sanding wooden surface

Cleaning the Wood

Ensure both the wood and your workspace are clean. Wipe down the wood with a damp cloth and clean the workspace thoroughly to prevent dust from settling on your work. 

Optional Grain Filling

For open-grained woods like oak, consider grain filling to achieve a smoother finish. You can use a grain filler that matches the wood’s natural color or the stain you plan to use.

With your wood prepared, let’s move on to the varnishing process.

The Step-by-Step Varnishing Process

Step 1: Prepare the Varnish

Begin by ensuring that you’re using freshly purchased varnish. An old varnish may have lumps that can compromise your finish. 

prepare varnish

To check the quality of your varnish before applying it to your project, test it on a scrap wood piece. Additionally, invest in a high-quality bristle brush made with natural, animal hair. Also choose one with a thick, durable heel, as the brush’s quality greatly impacts the outcome.

Step 2: Stir the Varnish

Stirring the varnish is critical to avoid air bubbles in your finish. Slowly and gently stir the varnish with a clean stirring stick. 

Avoid excessive shaking of the can, as it can introduce air bubbles. Pour the required amount of varnish into a measuring container marked with volume markings for precise measurements.

Step 3: Add Thinning Agent

To enhance the varnish’s performance and counteract surface imperfections like streaks and bubbles, put a thinning agent like gum turpentine into your container with the varnish. 

add thinning agent

The amount of thinner required varies depending on the coat you’re applying. Generally, a first coat may contain 20 to 25 percent thinner, while subsequent coats can have 5 to 10 percent.

Step 4: Application of Varnish

Now, it’s time to apply the varnish. Use a light touch, allowing up to the tip of your brush to bend during application. Start at the top of one side of your wood’s surface, applying varnish in one-foot-square sections, always following the wood grain.

Avoid going back and forth; stick to one direction. While the varnish is still wet, remember to slowly drag off the brush’s tip over the workpiece to smooth out any streaks or bubbles. Ensure your stroke aligns with your application stroke, following the grain.

applying varnish

Apply multiple thin coats rather than a couple of thick ones for optimal results. Once the two coats have fully cured, start light sanding your workpiece with 320-grit sandpaper. Afterward, clean it by vacuuming and wiping away all residue.

Choosing the Right Wood Varnish

Before you embark on your varnishing project, selecting the right type of varnish is essential. Here’s a brief overview of various varnish types and their suitability for different projects:


Varnishing wood is a rewarding endeavor that transforms your woodworking projects into works of art. By following this step-by-step guide and choosing the right tools, materials, and varnish type, you can achieve a smooth and lustrous finish that enhances the natural beauty of the wood and protects it for years to come. 

Remember, patience and attention to detail are your best allies on becoming a master of wood varnishing. So, roll up your sleeves, follow these instructions, and watch your wooden creations shine with brilliance. Happy varnishing!

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Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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