How To Apply Varnish Without Brush Marks

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If only everything we use in finishing a project were self-leveling, like the concrete or goop, we use to provide an undercoat in bathroom flooring, for instance.  Wouldn’t that be great?  Everything self-leveling?

Sadly, that is not the case.  Brush marks can abound if we don’t use proper preparation and application techniques, and that can drive us crazy.  We want that smooth finish, we want that durable finish, and we want what we want – a finish without brush strokes. 

Key Points:

  • Preparation of the wood is important.  If the wood is smooth, you’ll get a smooth finish, assuming you follow the right steps in applying varnish.  The goal is a finish without brush strokes.
  • Choosing the right bristle brush for the job is important:  a natural bristle brush for oil-based varnish and a synthetic brush for water-based varnish.
  • Varnish likes/needs a lot of finishing touches (no pun intended) to smooth out any runs or pools before the varnish has had a chance to set.  We call this “tipping off,” and it’s an important step in the process.
  • After the varnish has had a couple of days to cure, complete it by rubbing it out to your desired sheen.  A 0000-grade steel wool can help greatly in this step.

But what do we have to do to get what we want?  When it comes to varnish application, it is in both the preparation and the application, and both of them are equally important.  

What is Varnish?

Brushing Varnish

Varnish is a clear, transparent, hard protective coating or film. It is not a stain. It usually has a yellowish shade due to the manufacturing process and materials used, but it may also be pigmented as desired. It is sold commercially in various shades.

Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent, plus a metal drier to accelerate the drying. However, different types of varnish have different components.

After being applied, the film-forming substances in varnishes either harden directly as soon as the solvent has fully evaporated or harden after evaporation of the solvent through curing processes, the primary chemical reaction between oils and oxygen from the air (autoxidation) and chemical reactions between components of the varnish.

Varnish is used to protect and enhance the appearance of wood products, such as furniture, floors, and musical instruments. It can also be used to protect other materials, such as metal and plastics. Varnish is available in a variety of sheens, from matte to glossy.

Benefits of Using Varnish

  • It provides a protective coating that can help to prevent the wood from staining, cracking, or warping.
  • It enhances the natural beauty of the wood by bringing out the grain.
  • It can be applied in a variety of sheens, so you can choose the look that you want.
  • It is relatively easy to apply and maintain.

Drawbacks of Using Varnish

  • It can be difficult to remove if you decide that you no longer want it.
  • It can yellow over time.
  • It is not as durable as some other types of finishes, such as polyurethane.

Overall, varnish is a versatile and effective finish that can be used to protect and enhance the appearance of a variety of materials. It is easy to apply and maintain, and it comes in a variety of sheens to choose from. However, it is important to note that varnish can yellow over time, and it is not as durable as some other types of finishes.

Types of varnish

There are many different types of varnish, each with its own unique properties. Some of the most common types of varnish include:

  • Oil varnish: This type of varnish is made from a mixture of drying oil, resin, and solvent. Oil varnishes are typically very durable and offer good protection against moisture and UV rays. However, they can be slow to dry and may yellow over time.
  • Spirit varnish: This type of varnish is made from a mixture of resin, solvent, and drier. Spirit varnishes dry quickly and is relatively easy to apply. However, they are not as durable as oil varnishes and may not offer as much protection against moisture and UV rays.
  • Shellac: Shellac is a natural resin that is dissolved in alcohol to create a varnish. Shellac varnishes are very easy to apply and dry quickly. They are also relatively non-toxic and can be used on food-contact surfaces. However, shellac varnishes are not as durable as oil or spirit varnishes and may not offer as much protection against moisture and UV rays.
  • Polyurethane varnish: Polyurethane varnishes are made from a synthetic resin that is dissolved in solvent. Polyurethane varnishes are very durable and offer excellent protection against moisture, UV rays, and chemicals. However, they can be difficult to apply and may yellow over time.
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Other types of varnish

In addition to the types of varnish listed above, there are also a number of other types of varnish, including:

  • Acrylic varnish: Acrylic varnishes are made from acrylic resins and are very durable and easy to apply. They are also relatively non-toxic and can be used on food-contact surfaces.
  • Lacquer: Lacquer is a type of varnish that is made from nitrocellulose. Lacquers dry very quickly and are very hard. However, they are also very flammable and can be difficult to apply.
  • Epoxy varnish: Epoxy varnishes are made from two-part epoxy resins. Epoxy varnishes are very durable and offer excellent protection against moisture, UV rays, and chemicals. However, they can be difficult to apply and may yellow over time.

Choosing the right type of varnish

The best type of varnish for you will depend on the specific application.

If you are looking for a durable varnish that offers excellent protection against moisture and UV rays, then a polyurethane varnish or an epoxy varnish would be a good choice. If you are looking for a varnish that is easy to apply and non-toxic, then a shellac varnish or an acrylic varnish would be a good choice.

It is important to test the varnish on a small area of the project before applying it to the entire surface. This will help you to determine if the varnish is the right color and sheen for your project. It will also help you to check the varnish’s application and drying time.

What Are The Differences Between Water-Based Varnish and Oil-Based Varnish?

Water-based varnish and oil-based varnish are two of the most common types of varnish used to protect and enhance the appearance of wood. They both have their own advantages and disadvantages, so it is important to choose the right type for your project.

Here is a table that summarizes the key differences between water-based and oil-based varnish:

FeatureWater-based VarnishOil-based Varnish
SolventWaterSolvents such as mineral spirits or turpentine
Drying timeFasterSlower
OdorLess odorousMore odorous
DurabilityLess durableMore durable
Shelf lifeShorterLonger
Clean-upEasierMore difficult
Environmental impactLess harmful to the environmentMore harmful to the environment

Here is a more detailed explanation of the differences between water-based and oil-based varnish:

  • Solvent: Water-based varnish is dissolved in water, while oil-based varnish is dissolved in solvents such as mineral spirits or turpentine. This difference in solvent affects the drying time, odor, and durability of the varnish.
  • Drying time: Water-based varnish dries faster than oil-based varnish. This is because water evaporates more quickly than solvents.
  • Odor: Water-based varnish has a less odorous than oil-based varnish. This is because water is a non-toxic solvent, while solvents such as mineral spirits and turpentine can be harmful to breathe in.
  • Durability: Oil-based varnish is more durable than water-based varnish. This is because oil-based varnish contains resins that harden over time, creating a hard, protective coating.
  • Shelf life: Water-based varnish has a shorter shelf life than oil-based varnish. This is because water-based varnish can spoil if it is not stored properly.
  • Clean-up: Water-based varnish is easier to clean up than oil-based varnish. This is because water-based varnish can be cleaned up with warm soapy water, while oil-based varnish requires the use of mineral spirits or turpentine.
  • Environmental impact: Water-based varnish is less harmful to the environment than oil-based varnish. This is because water-based varnish does not contain harmful solvents.

How To Apply Varnish Without Leaving Brush Marks

Applying Varnish

It’s the brush marks that upset us and leave our project looking very unprofessional.  Avoiding brush marks has to do with proper preparation and correct application.  

How To Prepare Wood For A Varnish Application

First, let’s consider what we need to gather before we begin:

  1. Gather your supplies. You will need the following supplies:
    • Varnish of your choice
    • Brush.  Use a natural bristle brush with oil-based varnish and a synthetic bristle brush with water-based varnish.
    • Sandpaper (180-grit and 220-grit)
    • Tack cloth
    • Mineral spirits or turpentine (for cleaning the brush)
    • Safety glasses and gloves
  2. Prepare the work area. Make sure the work area is clean and free of dust. If you are working indoors, open a window or door to ventilate the area.
  3. Inspect the wood.  Make sure the wood is free of any dirt, debris, or old finish.  If the wood is dirty, clean it with a mild soapy water solution.  If the wood has an old finish, remove it with a paint stripper or varnish remover.
  4. Sand the wood.  Sand the wood with a 180-grit sandpaper to remove any rough spots and to open the pores of the wood.  Then move up to a 220-grit sandpaper to create a smooth surface, and maybe even continue to a 600-grit sandpaper.  We want to eliminate all surface imperfections, and we want the varnish to create a smooth finish on the wood’s surface. 
  5. Wipe down the wood.  Use a tack cloth to remove any dust from the wood, or take it outside and use compressed air to blow any dust away, or both, just to be sure.

Surface preparation is essential to a smooth varnished surface, so don’t skimp on the sandpaper preparation of your project.

Your wood is now ready for varnish application.  Generally speaking, too, you want to make sure your working environment is clean and bug-free.  You don’t want to find a fly, for instance, stuck in the varnish – we mention this because it has happened to us in the past.  No bugs.

Varnish Application

The wood is now ready to receive, and you are ready to apply.  Let’s go through the process now and see if we can avoid leaving brush marks behind, including matching the right brush with the right varnish, as well as how to prepare the varnish for application.

  1. Use the right brush. A good brush for applying an oil-based varnish is a natural-bristle brush with a flat ferrule. The bristles should be soft and flexible so that they can spread the varnish evenly without leaving brush marks.  For a water-based varnish, though, always use synthetic bristles because water-based varnish can cause the natural bristles to splay and separate, raising the chances of leaving brush marks in the varnish.  As a final wood on the right brushes, don’t skimp on them.  Pick a quality brush, and pay up for it – it will perform the task better and, if properly cared for, will last a long time.  We’ve read of woodworkers keeping a brush in great shape for 20 years by taking the time to clean thoroughly after each use.
  2. Thin the varnish. Thinning the varnish will help it to flow more smoothly and evenly, making it less likely to leave brush marks. You can thin oil-based varnish with mineral spirits or turpentine; you can thin water-based varnish with distilled water.  The varnish container will suggest the proper ratio of thinner, and it’s good to follow those suggestions.
  3. Apply the varnish in thin coats. Thick coats of varnish are more likely to leave brush marks. Apply the varnish in thin, even coats, allowing each coat to dry completely before applying the next.
  4. Work with the wood grain. Apply the varnish in the direction of the wood grain. Brushing with the wood grain helps to minimize the appearance of brush marks, whereas you are far more likely to create brush marks brushing against the wood grain.
  5. Use a back-brushing motion. After you have applied the varnish, use a back-brushing motion to smooth out the finish. This will help to remove any brush marks that may have been left behind.
  6. Sand between coats. Sanding between coats of varnish will help to create a smooth, even finish. Use a fine-grit sandpaper, such as 220-grit, to sand between coats.  A 0000 grade steel wool can also be used to smooth between coats and does a good job of pushing down any brush strokes that may present. Be sure to follow this procedure for all subsequent coats.
  7. Allow the varnish to dry completely. Varnish needs to dry completely before it will be fully cured. Allow the varnish to dry for at least 24 hours before handling it.

Here are some additional tips:

  • Work in a well-ventilated area. Varnish fumes can be harmful, so it is important to work in a well-ventilated area.
  • Clean the brush immediately after use. Varnish can be difficult to remove from brushes, so it is important to clean the brush immediately after use. Use mineral spirits or turpentine to clean the brush.
  • Test the varnish on a small area first. This will help you to determine if the varnish is the right color and sheen for your project. It will also help you to check the varnish’s application and drying time.

Video Demo of Tipping Varnish

We mentioned tipping off in the Key Points section above and thought we would expand on that with a video.  We found a boatbuilder, actually, who offered an online course on varnishing.  This video is on the final step, the tipping off.  It’s a bit long at 15 minutes, but it’s worth a watch.

The point of the exercise is a finish without brush strokes.  Take your time, follow the steps outlined above, and you’ll have that finish without brush strokes, as well as a professional appearance.

Last update on 2024-04-13 / Affiliate links / Images from Amazon Product Advertising API

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