Don’t choose just any paintbrush for applying polyurethane. Achieve a smooth finish on your next woodworking project with the best brush for polyurethane.
ByTimothy Dale| Updated May 19, 2021 12:27 PM
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Polyurethane is a durable, attractive finish that comes in several different types, including oil-based, water-based, and a water-based and oil-modified formula. It’s typically used to seal wood products, protecting them from moisture, dirt, and damage. Like paint, polyurethane is applied to the material’s surface with a brush.
The best brush for polyurethane differs depending on the intended application. Most smaller projects benefit from a narrow brush, while larger projects can be completed to the same level of quality in a shorter period of time with a wider brush. Read on to learn about the factors to consider as you shop, and then explore some of the top choices for the best brush for polyurethane application.
What to Consider When Choosing the Best Brush for Polyurethane
Before selecting a brush to apply the polyurethane, consider the size, shape, and design, including the type of bristles, the handle, and the ferrule. Don’t forget to factor in the type of polyurethane and its intended use to achieve the best coverage and finish. Here are several details to keep in mind when choosing the best brush for polyurethane application.
Brushes can be made with natural or synthetic bristles. Some forgo the bristles entirely, opting for an angled foam material to spread the polyurethane. The best option for the project depends on the polyurethane base, the size of the project, and the shape of the material.
The brush size you choose should be based on the size of the project or the intended purpose of the brush. Common brush widths are 1-inch, 1.5-inch, 2-inch, 2.5-inch, 3-inch, 3.5-inch, and 4-inch. Brushes that are 2 inches or smaller in width are ideal for applying polyurethane in tight corners or at awkward angles with controlled precision.
Choose a 2- to 3-inch brush for most woodworking projects. These brush widths provide good coverage but can still reach into some smaller spaces. Larger projects, like finishing a table or bed frame, can benefit from a 4-inch brush that quickly covers a lot of surface area.
The ferrule of a brush is the metal part that connects the bristles to the handle. The metal needs to be strong and stable; otherwise, the bristles can bend, break, and detach from the brush. They can become stuck in the can of polyurethane or on the project, leaving an impression in the applied polyurethane that you’ll then need to touch up.
The ferrule is typically made of aluminum or steel intended to support the bristles and keep them together. The high durability and corrosion resistance of both metals helps ensure that the brush and bristles last for more than one use before needing to be replaced.
To maneuver, angle, and direct the brush, you need to grip the handle securely. It’s not impossible to apply polyurethane without a sturdy handle, but it also isn’t easy. For these reasons, don’t ignore handle design when choosing the best brush for polyurethane.
Bristle brushes usually have smooth, flat wooden handles that are easy to grip to accommodate both full strokes and small, precise strokes. Foam brushes may have a narrow wood, plastic, or metal handle extending from the ferrule like a cylindrical rod or stick. This small diameter is more suited for precise strokes than broad application.
Polyurethane-based sealants and finishes are available in either oil-based or water-based options, depending on the desired appearance.
Before deciding on the best brush for polyurethane application, consider how and where you’ll use it. Bristle brushes with lower widths and foam brushes are ideal for smaller projects, while larger brushes are better for smooth, broad strokes. If you’re applying polyurethane to a high-traffic object, like a dresser or a closet door, it’s important to use at least four coats of water-based polyurethane or at least three coats of oil-based polyurethane.
Decorative objects purely for display that often sit for weeks or months without being touched only need two to three coats of water-based polyurethane or one to two coats of oil-based polyurethane. Regardless of the material, wait for 2 to 3 hours between applying additional coats.
Our Top Picks
This list includes all three options—natural bristle, synthetic bristle, and foam—to help users find the best brush for polyurethane application. Here’s a look at some of the top products on the market based on the above-mentioned factors.1Photo: amazon.com Check Latest Price
This brush from Wooster is an excellent option for applying polyurethane to average-size woodworking projects or furniture due to its 2.5-inch width that’s suitable for both broad and precision strokes. The tapered bristles allow the user to direct the brush tip into corners to ensure that the entire surface is evenly coated.
The brush features a smooth wooden handle that fits comfortably in the user’s hand, providing balanced control over each stroke. Synthetic bristles made of polyester filaments achieve a smooth, soft finish with feather-light strokes. The brushed-steel ferrule is resistant to rust and corrosion, helping to ensure that the bristles remain secure through multiple uses.2Photo: amazon.com Check Latest Price
Choose from among five different brushes for polyurethane application in this affordable value pack from Pro Grade. The pack includes a 1-inch flat brush ideal for narrow pieces, odd angles, and small corners and a 1.5-inch tapered brush suitable for crisp, clean corners and angles. Choose the 2-inch tapered brush, 2-inch flat brush, or 2.5-inch tapered brush for broad strokes on standard woodworking projects, like a stool or coffee table.
These synthetic bristle brushes feature a stainless steel ferrule that resists rust and corrosion while tightly holding the polyester filament bristles. Each brush also boasts a smooth and contoured hardwood handle for a comfortable grip.3Photo: amazon.com Check Latest Price
The natural bristles on this brush from Purdy are made by blending ox hair with a white China bristle for added resilience and smooth application of oil-based polyurethane. A strong, durable stainless steel ferrule helps to ensure the brush doesn’t lose any bristles while in use. The tapered bristles are 1.5 inches wide, allowing the user to properly coat corners and difficult angles without issue.
Use this brush to apply a variety of oil-based coatings or sealants, including paint, enamel, varnish, polyurethane, and lacquer. It boasts a slim hardwood handle with a hanging hole for easy organization and storage that won’t damage the bristles. The brush is also available with flat bristles and in 2-inch, 2.5-inch, and 3-inch widths.4Photo: amazon.com Check Latest Price
The synthetic bristles on this brush from Purdy are made with a combination of nylon and polyester that soak up water-based polyurethane, providing a soft, even finish. The smooth hardwood handle is easy to hold and control for precise brushstrokes. The brush also features a brushed copper ferrule with superior rust and corrosion resistance, helping to ensure that the bristles don’t fall out after extended use.
Use this brush for touch-ups on trim or small- to average-size woodworking projects, including window shutters and door molding. The 2-inch width is suitable for long, broad strokes, and the tapered bristles reach narrow corners and tight angles, providing full coverage to the entire project.5Photo: amazon.com Check Latest Price
Don’t fight with fragile bristles that can bend, break, or fall out when this Wooster foam brush is a great alternative for applying polyurethane to smaller projects like a mailbox, bird feeder, or chair legs. The foam brush soaks up water- and oil-based polyurethane and measures 1.5 inches in width for a smooth, controlled application over a small surface.
This brush has a white plastic handle that is a part of the hard plastic ferrule. It has a rigid core to keep the handle and ferrule stiff while the foam flexes and bends to achieve the best results. The low price and moderate reusability of this brush make it an excellent option for the casual DIYer.6Photo: amazon.com Check Latest Price
Brushes smaller than 4 inches wide are great for small- to average-size woodworking projects, but they lack the girth of this 4-inch brush from Wooster that can quickly apply a coat of polyurethane to a table, a door, or even a wall. The brush features synthetic bristles made of nylon and polyester for a fine finish with water-based polyurethane.
The flat bristles glide in broad strokes over the material, making it easier to apply the polyurethane in even layers. This produces a soft finish with a balanced color palette instead of splotchy, uneven coats. A solid plastic handle and a brass-plated steel ferrule help secure the bristles and maintain the high durability of the brush.
FAQs About Brushes for Polyurethane
Achieve a smooth, clean finish on your next woodworking project by choosing the most appropriate brush for applying polyurethane. If you still aren’t certain about which bristles are best suited for polyurethane or if a foam brush is a good idea, keep reading for answers to these and several more frequently asked questions about the best brush for polyurethane application.
Nylon and polyester are commonly used to make synthetic bristles. While these materials aren’t suitable for oil-based polyurethane, they are a good option for applying water-based polyurethane.
Yes, it is OK to use a foam brush to apply polyurethane. However, it isn’t the best choice for larger projects because the foam doesn’t spread the polyurethane as well as a synthetic or natural brush. Use a foam brush to apply polyurethane to smaller projects, like finishing a birdhouse.
For the best results, choose a natural bristle brush with a durable ferrule and tightly packed bristles to apply oil-based polyurethane.
Before using any polyurethane, sand down the material with 220-grit sandpaper to achieve the smoothest possible surface. Then, wipe down the material, removing all dust particles with a clean cloth. Spread the polyurethane, allowing each coat to dry between 2 and 4 hours before applying the next coat. Use sandpaper again to gently remove brush marks from the material’s surface, and consider applying a wood polish for a near-flawless appearance.
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