Start to Finish: Selecting Brushes for Today’s Paints

Guest author: John Fattor, Contractor Sales and Training Coordinator, Wooster Brush

Brushing is the oldest method of paint application, and it takes the longest to master. But the brushes used successfully for decades with alkyd and oil-based paints aren’t suited to the waterborne paints that now dominate the market. Different brushes are required for the job.

Advancements in Brush Filament Technology
Women may consider them a curse in their own hair, but the split ends from Chinese hogs were the benchmark of quality paintbrush filament for well over 100 years. The virtue of Chinese hog bristle is a natural splitting at the end called “flagging,” which helps the brush hold paint more effectively than other natural animal bristles. Furthermore, the multitude of small hairs at the tip of each bristle create a finer, smoother finish. When the supply lines for China bristle were interrupted during World War II, the painting industry nearly slowed to a halt.

The industry searched for alternatives, but substitutes such as Indonesian bristle or horsehair did not do the job the way China bristle always had. So the U.S. Navy commissioned DuPont to develop a synthetic substitute for Chinese hog bristle. DuPont responded by incorporating two unique China bristle attributes into their nylon synthetic filament: its wonderful split ends and its tapered shape (larger at the bottom and thinner at the tip).

Synthetic filaments proved to be an acceptable alternative to natural bristle; however, decades later, with today’s low VOC water-based paints, frizzy ends have become a liability. Latex paints dry faster than oil-based products, quickly clogging up those once-valuable flagged tips and inhibiting smooth release. So the brush industry has followed the lead of women by getting rid of its split ends.

Also, the water in latex paints causes natural bristle to soften and swell, which makes the brush lose its shape and become soft. Nylon absorbs far less water than bristle, and polyester filaments are impervious to water, so they are better suited for waterborne paints. Today’s advanced filament technology may well produce some of the best brushes ever made; thanks to new finishing processes, today’s brushes have better pick up and better tipping (the brushing technique where the tips of the bristles are used to smooth the applied finish), creating a great finish as well as providing increased production.

So while pure Chinese hog bristle still works well with solvent-based coatings like epoxies and polyurethanes, the filament tips found in today’s professional brushes for water-based paints no longer resemble what Mother Nature created in China bristle.

Take a Brush for a Test Drive: How Manufacturers Test Their Brushes
Top paint applicator manufacturers employ brush development engineers who have many years of experience. After designing a new brush, all engineers are faced with one important question, “Have I made a better brush?” The best way to evaluate strengths and weaknesses of a brush is to use it: dip it into paint and test it on a typical surface to gauge these three key characteristics:

  1. How much paint does the brush pick up and release?
  2. How far can you push the paint before the paint stripe breaks?
  3. Is it easy to clean after a day’s work?

Painters or retailers can use this analytical process to compare the performance qualities of different brushes. Have one of your top brush guys do the test. Start with a 4’ x 8’ test surface —drywall is ideal — and a quality latex paint. Prime your brushes by dipping them in water and spinning them out, and then dip the brush the way you normally do. Start at the top of the test surface and paint one continuous stroke until you have a break. Repeat these steps with each brush you want to test.

For a good visual comparison, be sure to do your second paintout near the first. Using this method makes it easier to compare two or more brushes against each other. You will find that all brushes are not created equal.

The Best Method for Cleaning Brushes
Most quality brushes can be used many times if they are properly cleaned after use. The choice of filaments used in the brush will affect its ability to be cleaned. Note that latex paints form a greater chemical bond to polyester filaments than to nylon, which means more time and effort is required for cleaning — so if you want a brush that cleans more easily, more nylon filaments are preferred. You can identify how much polyester is in a brush by looking at the packaging or handle stamping: the ingredient mentioned first should be the main filament. For example, a brush that’s labeled “Nylon/Polyester” is likely to have more nylon (at least 51%) than polyester

We suggest this three-step process for cleaning.

  1. Get as much paint out of the brush as possible by rinsing it with water.
  2. Add a pumice-based cleaner (such as Lava, Go-Jo, etc.) to the brush and rub it into the filament, working it fully into the brush.
  3. Rinse the brush with water while using a brush comb to straighten the filaments.

After spinning the brush, hang it on a hook to dry. Another drying option is to wrap a brush in craft paper and use a rubber band to hold the paper in place. The craft paper allows the brush to breathe as it dries.

Following these cleaning steps means your brush will be ready for another day of work tomorrow.

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