The Anatomy of an Artist Brush

Brush making is a very old art that in central European traditions was combined with the making of brooms. England, France and Germany have the longest traditions in brush making.

The modern artist brush consists of three parts. The tuft (T) is the bundle of hair, bristle or fiber that holds and releases the painting liquid. The visible portion of the tuft, about half its total length, is the length out, which consists of the belly or widest middle part and the tapering point or tip (in a round) or edge (in a flat).

The ferrule (F) is the metal collar that connects the tuft to the handle, supports the tuft during painting, protects the end of the wood handle from moisture, and determines the size and shape of the brush.

The handle (H) is made of a dense hardwood selected for straightness. Plastic handles have been tried but customer's associate plastic with low quality and lack of durability.

The Tuft is made from pelts or ears of an animal. They are first shampooed and then hung to dry. Sable and squirrel pelts are sometimes oven cured at low temperatures to increase the hair elasticity or "spring."

Brush hairdressers scissor the prepared hairs or bristles from the pelt, hold large tufts between thumb and fingers and use a fine comb to separate the hairs and remove hair fragments, fine hairs and stubborn debris. Hairs are meticulously sorted, separated by length and cleaned of any broken pieces. Hairs of the same length are bundled for sale to brush makers; because there are fewer of the longest hairs on an animal, these are more expensive.  Brush makers who do not do the hairdressing themselves carefully unbundle and inspect a shipment when it is received.

To make a tuft by hand, the brush maker pinches out or counts the exact number of hairs required for the brush size, then places these hairs (pointed end down) inside the brush maker's mold; a hollow brass cylinder with thick sides and base, somewhat resembling an oversized thimble, whose inner contour defines the shape of the finished brush (rounded at the bottom for rounds, and flat for flats). The cup is tapped repeatedly on a stone slab, which drives the tip of every hair to the bottom of the cup.

A different procedure, called stacking, is used for liners or other tapering brushes that do not have a pronounced belly. As many as five lengths of hair are used, carefully arranged with the longest hairs at the center of the tuft and inserted into the cup butt end down, with the points exposed.

Once the hairs have been cupped to the appropriate shape, the exposed ends are wrapped tightly at the base with string and the tuft is removed from the cup. If the brush is a round, the string is tied off with a knot and trimmed. The brush maker then manipulates the tuft with the fingers to perfect the shape of the belly and point. The inner end of the tuft is then sheared off flat to the desired length, and the tuft is inserted into the metal ferrule from the wide (handle) end, pulled through to expose the desired length out, then secured with a penetrating, waterproof adhesive and hung, tuft down, to dry. (Synthetic tufts are made of extruded fine filaments of plastic cut into desired lengths and sorted by machine.) Tufts are sometimes purchased cupped and tied for assembly by brush makers, but they more often use a set that consists of the tuft already glued into the metal ferrule.

 

The Ferrule (metal ferrules) were first commercially used in brush making around 1890. The highest quality ferrules are seamless; not made of a flat piece of metal rolled into a cylinder. Fine quality brushes are mounted into ferrules made of a hard but malleable, corrosion resistant metal such as brass or copper; these are typically plated with nickel, silver or (rarely) gold. (Ferrules on cheaper brushes are made of softer aluminum or tin, which bends too easily.) They represent almost a third of the total cost to manufacture a brush.

In nearly all fine commercial brushes the ferrule is double or triple crimped at the handle end (as in the drawing at left) to fasten the handle securely and keep water from seeping inside. Ferrules for flat brushes may be cylindrical in their original shape and flattened to achieve a particular brush style. Natural quills from the feathers of ducks, geese, and other fowl are sometimes still used.

The Handle, made of wood is chemically sealed, then finished by dipping in lacquer or polyurethane. The end inside the ferrule is flat and the butt end of the tuft is glued directly to it. This is the weakest part of the brush, because the end is not lacquered or varnished so that the adhesive can bond tightly with the wood. Prolonged soaking will expand the wood and loosen the adhesive holding the tuft in place. Acrylic handles are also used, particularly for synthetic brushes. Handles vary widely in diameter and length, but generally are shorter for watercolor brushes than for oil/acrylic brushes.

Brush Sizes. Round brushes are sized using a standard numbering system that ranges from #00000 or #000 for the smallest brushes, then typically runs #00, #0, #1 to #12 in single number intervals, then #14 to #20 in even number intervals, and sometimes #24 or higher for the largest brushes.

It is unclear as to how these numbers are defined or assigned to a brush size. The best analogy is that they are like shoe sizes, fairly standard but somewhat different across manufacturers and styles. The numbers usually identify the relative sizes of brushes within the same type of brush by the same manufacturer. But across manufacturers, brushes of the same numerical size and type will typically not be exactly the same actual size or shape.

Because English brushes are typically made with wider bellies, there are effectively two numbering systems, English and continental (or European). The English numbers refer to a larger brush: an English size 8 brush is equivalent to a German size 9, an English 12 to a German 14, and so on. Flats are usually sized by the measured width of the edge of the ferrule, although some companies size their flats with a numbering system similar to rounds.

Brushes are handmade from raw materials that vary widely in quality and availability. For that reason, brushes are always subtly different from each other, even when they come from the same manufacturer, in the same size and in the same series number. Even synthetic brushes show this variation; a pleasant reminder that these are among the oldest tools made for the human hand.