Paint Brush Bristles: What Kind Are Best?
Here's a question that we received from one of our followers, RAFAJULO on YouTube.
Every time I use a finish (Polycrylic), I seem to get small air bubbles as I'm spreading. I stir slowly, I don't shake the can, I brush it on slow but I always have this problem. What am I doing wrong?
Maybe nothing. I have learned that different bristles are better for different finishes. I use a synthetic brush and have no issues, so maybe try that. Also, when I get bubbles (and it happens often), I have to "tip off" the finish by just gently skimming over the surface. That pops out some of them. If that doesn't work, a very light pass with a butane torch will pop them out as well.
And then again, it may not be you.
I work in an open-air carport so temperature and humidity can have a dramatic affect on my finishing results. The hotter and/or more humid it is (think July here in North GA), the harder it is to get a bubble-free finish without a lot of care.
And come to think of it...having said all that, this is probably a good time for a word on paint brush bristles.
So FYI paint brushes are made with two general types of bristles. Synthetic, which are man-made, and Natural, which are made from animal hair.
“So what are the differences?” And that would be a great question. While there have been entire books written about bristles, I’ll try to answer this as simply as possible.
In general, use synthetic bristle brushes for water-based finishes, such as latex or acrylic paint, water-based polyurethane (like Polycrylic), or water-based stains. Natural bristles tend to soak up a lot more water than a synthetic bristle, so they can get overly soft and give you a less-than-sharp finish, over time.
Synthetic bristles are generally good for finishes that can be cleaned up with water because they don’t “pick up” paint as well as their natural counterparts…for the most part.
What is “pick up”, you ask?
Pick up is absorption. Meaning, a brush with good pick up needs less dipping in the paint bucket. Its bristles tend to soak up the paint more readily, so you can paint more per stroke. And that’s a good thing…except good pick up is typically balanced out with lower durability. But I digress...
Synthetic bristle brushes are available in either basic “synthetic” or in a variety of Synthetic Blends, such as a Nylon/Poly Blend, which uses the blend to help the brush maintain its shape over time, pick up better, etc, among other things.
A Chinex brush would be at the top end of the synthetic spectrum, and well worth the investment. Chinex brushes are touted for their ability to handle both oil and water-based finishes, hold their shape and offer excellent pick up. They're almost the best of both worlds.
Natural bristle brushes might also be called Black China, White China, Sable or Ox Hair Blend OR many other industry names. These guys are great for oil-based finishes, aka finishes that require something like Mineral Spirits to be cleaned. Like traditional stains, oil-based paints, polyurethanes, enamels, shellac and varnish. Natural bristle brushes also typically provide a smoother finish.
A White China brush is known for its smooth finish. And an Ox Hair Blend is prized for its incredibly smooth results. A Black China brush is a little stiffer than the previous two and would be a great choice when doing a large volume of painting because they’re more durable.
When painting a more textured surface though, a natural bristle isn’t a great choice because they are all relatively delicate. A rough surface (such as textured brick or stucco) will break off the ends of the bristles and give them a frayed, “fuzzy” look. That’s when you demote your brush to sawdust removal from the crevices on your table saw.
IN THE END
We use our fair share of cheap brushes from Dollar Tree that we use once and then throw away, but when the finish is critical, there’s nothing like a great brush to make it happen. It pays to have at least one awesome mid-sized brush hanging on the wall, just for those special projects.
A reasonable quality brush should cost you somewhere between $10-20, although some may be more, depending on the size and brand. We happen to like Purdy Brushes and I can vouch for their quality after having used them for well over 20 years. IMO a Purdy is a brush you hand down to your kids. They're that good.
Check out a couple of our favorite candidates for your "One Awesome Brush". Like the Purdy Chinex Elite Club 2 Inch Brush or the Purdy Black Bristle Swan 3 Inch Brush. It would be hard to go wrong with either of them and they wont break the bank.
I hope that helps! And if you have any questions for us about woodworking projects, techniques or tools, please CONTACT US. We'd love to see if we can answer your question in detail.
Til then...peace, love and sawdust. Ricky