Woodworker's Journal 2011-35-Winter, страница 58

Brushing Up On Finishing

All brushes are not the same. Here's

how to pick the best for finishing.

What's more efficient than a spray gun, more versatile than a roller and more relaxing than any other method of applying a finish? The answer is "a brush" — that old standby that is constantly being challenged by newer application methods, yet never quite replaced. A good brush can apply most any type of finish, thick or thin, on any type of surface without wasting material or creating overspray and, with proper cleaning and care, will continue working year after year.

Choosing a Brush

Before we talk about different types of brushes, it makes sense to get our terminology straight. Take a look at the illustration (next page) for the names of the different parts of the brush.

Most of the brushes you find at the paint or home store are paint brushes, not varnish brushes. Paint brushes are cut flat on top while varnish brushes are chisel shaped at the ends of the bristles. Paint and varnish brushes can be straight or angled (skewed), and which you use is a matter of taste and comfort.

When you press a chisel-end varnish brush down at the correct angle, the ends of the bristles will form a smooth, thin line along the wood (see photo on page 60). It will look as if there is only a single layer of hair at the end of the brush in contact with the wood, thus spreading the varnish smoothly with few brush marks. This quality is less important when you apply thicker paints, so paint brushes are usually not chisel ended.

Types of Bristles

Brush bristles can be made of either natural hair or synthetic fibers. Water causes natural hair to splay when it gets wet, so synthetic fibers are best for waterborne coatings and paints. I like nylon bristles for clear waterborne finishes, because they are the softest of the synthetic fibers. Polyester, nylon polyester mixtures and other synthetic bristles are good for thicker paints, and they are great all around choices.

Natural bristle brushes are made from a variety of different types of animal hair, and they often are named after the animal who unwillingly supplied it. Badger, sable, ox and squirrel hair brushes really do come from those poor critters. China bristle is made from the hair of a Chinese hog, and Camel brushes (note the capital letter) are soft bristle brushes

To create the chisel shape of a varnish brush, the hairs must be set into the ferrule in graduated ranks or rows (see Plug Detail at upper right), a process that contributes to its higher price. A topnotch 2" varnish brush may cost upwards of $30.

Natural white China bristles are generally softer than natural black China bristles; however, some manufacturers do dye their white bristles black. Angled brushes, like the ones at left, let you get into tight two-directional corners.