BRUSH, a tool used for moving, distributing, collecting, or removing materials of a powdery, granular, or linty nature—either dry, such as dust, or liquid, or combined with a liquid, or semi plastic, such as paint or mud, also a device to transmit electricity to or from moving parts. The derivation is from 0. Fr. broce, brushwood; Fr. brosse. One of the first types of known brushes is the besom, a bundle of twigs or brushwood tied to a wooden handle by means of cane, from which developed the corn broom and whisk, and now the fibre broom so popular in America. A broom may be said to be a brush with a long handle.
The range of materials available for brushmaking is now very great, as the hair from many animals and the fibrous materials, derived from many varieties of vegetable growth, as well as the recently developed synthetic (plastic) materials such as exton, are now called into use by the manufacturer. The more important materials employed are the hairs of the pig, boar, horse, badger, goat, bear, skunk, ox; protective hairs plucked from the fur of the sable, marten, squirrel, etc., sometimes called camel hair, and vegetable products such as piassava (bass), palmyra fibre, tampico, palmetto, bassine, kittool, Mexican fibre, whisk or broom-root, broom corn, Coco, cane, and whalebone. A great amount of cot ton is used also particularly in twisted-in-wire brushes.
The selection of the brush material depends upon the use to which the brush is to be put, extending all the way from the stiffer brush material for moving foundry slag, down to bristle for re moving the finest dust on a polished floor, and from the artist's application of his water colours to the picture (frequently called a pencil), to the removal of thick mud in the gutters. In the case of personal brushes, it ranges from the stiffness necessary to penetrate a healthy head of hair or to take the grime from a me chanic's hands to the softness to remove excess face powder from milady's cheeks.
To make use of the available materials for these purposes, they must be held securely in a handle, which may be long or short, depending upon the use of the brush, and may be made from any wood, metal, hard rubber, or the numerous comparatively recently developed plastics, such as pyroxylin and Bakelite, or materials of animal origin, such as ivory, bone, and tortoise shell. Although stiff brush material is frequently designated by the general term "bristle," the correct use of this word should be confined to the stiff hair obtained from the hog, pig, or boar, the best and stiffest of which come from the colder and wilder districts of Europe and Asia, being marketed through Russia, Japan, China, and India. Horsehair, which is used very extensively for dust brushes, comes mainly from countries where labour cost in preparing material for the market is low enough to meet competition.
Among the fibres are piassava, obtained from the leaf-stalk and trunk of the palm Attales Funi f era which grows in the Brazilian forests, taking its name from the principal port of shipment, Bahia, and also from leaf-stalks of the African palm. Both Bahia and African piassava are known as bass, the latter being a much stiffer and coarser fibre than Bahia piassava. Another Brazilian fibre known as Para, but more commonly as monkey bass, is used where a softer material is required. There are several sorts of Mexican fibre (locally known as Istle) and obtained from Agave Heteracantha, the best known being called "Tampico," as it is largely exported from that Mexican port.
Kittool is obtained from the Indian palm Caryota Urens; and bassine (also an Indian product) from the Palmyra palm (Boras sus Flabelli f ormis) . Whisk is obtained from Mexico, France, and Italy.
All these materials are bleached, dyed, and processed, even to the extent of imitating the natural bristle "flag" or split end in fibre.
(a) Pitch or Cement Setting.—In the case of set brushes, the ma terial is made into knots (almost the only way to make a bristle brush with the flags out) of the required size, dipped into boiling pitch, then bound by means of a thrum, again dipped into boiling pitch and then inserted into the hole in the back, which has been previously bored either by hand or by machine. Sometimes they are pegged into place.
(b) Machine Filling.—Machines are now playing a large part in the manufacture of brushes, and are replacing hand-drawing and pitch setting except for the very expensive brushes. By means of machines the knots are punched into holes in the solid backs and are secured by a staple in the same operation. Automatic drilling and tufting machines produce large quantities of brushes at very low cost.
(c) Hand Drawing.—In the case of hand-drawn brushes, the knots or tufts of brush material are drawn into the holes from the back of the brush with wire. When all the holes of the brush are filled, the brush is completed by means of a veneer which is glued or screwed on the back and then finished by the brush finisher. Afterwards the bristles or other materials are levelled by means of shears and the brush is ready for use. One of the principal uses of this method is the metal back hair brush in which bristle tufts are drawn into the holes in die cast aluminium backs. In the finished brush, the wire lies neatly in open grooves in the back which serve as a decoration.
Another method of hand-drawing is known as trepanned work. The holes are bored only to a certain depth and connected at the bottom with a long hole running the length of the brush stock. In the latter hole, the thread with which the brush is drawn is placed and secured at one end, the thread is drawn out of the hole in a loop and the knot is placed in the loop and drawn in from the end of the brush. This is the only method which can be used for hand-drawn ivory brushes and at one time was also used for ebony brushes, although the latter are now also staple set. Bone-handled tooth brushes were made in this way.
(d) Twisted-in-Wire.—The bristle or other material is secured by means of two wires between which it is twisted. In some cases the ends of the twisted wire are inserted into a handle of wood, celluloid or Fullerex. This makes a brush with material all around the centre wires. They are frequently bent into a loop to make a brush with a substantial face, and this type represents a very large proportion of the brushes used in the home.
(e) Rolled in Metal or Steelgript.—The most recent and possibly the most far-reaching development in brush construction that has taken place in a great many years is the rolling of brush material into a metal channel. The metal channel folds over a wire, holding brush material in place, and its grip permits greater freedom from shedding or dropping out of brush material than any other type, except possibly the twisted-in-wire. This makes it invaluable for a number of uses, particularly in the food industry and in rubber manufacture where shedding is troublesome.
Such construction enables brushes to be made in strips, of lengths limited only by the length of metal strip and wire that can be fed to the automatic machine which forms the strip into a channel. This machine likewise feeds the brush material uniformly under the wire, and clamps it into a solid brush strip, and may even trim the ends of the brush material to the desired uniform length, and automatically cut it off to the strip length required to meet the numerous uses to which it is to be put.
The brush consists of metal and brush material only, no wood or other backing which might split and release the tufts being used. After the brushes are made in strip form they may be wound into spiral form for use as rotary brushes on many types of industrial ma chines. These cylindrical brushes can be made practically any length and diameter, in this way improving both the machine and the product.
(I) Household Brooms and Brushes.—These consist of sweeping brooms, carpet brooms, yard brooms, scrubbing brushes, stove brushes, hearth brushes, shoe brushes, etc., all materials and methods of manu facture being used.
(2) Toilet Brushes.—Tooth brushes are almost entirely staple set in celluloid handles, white bristle having been mainly used, but there is a recent movement to use natural coloured and black bristle, owing to its superior wearing qualities. Tooth brushes with synthetic ma terials are also now being marketed in small quantities.
Other Sorts.—In this section may be included hair brushes, clothes brushes, hat brushes, shaving brushes, etc. These are manufactured by pitch setting, stapling, hand-drawing, and twisted-in-wire. The ma terials used consist of wood stocks and twisted wire handles for clothes and hat brushes and other brushes of this type. Wood, ivory, tortoiseshell, and plastics are used for the handles of hair brushes, also for shaving brushes. Shaving brushes are made like string bound sash tools, the only difference being in the handle, which is very much shorter. Badger or bristle is used mostly for shaving brushes; for the other types of brushes, bristle, horsehair, and in the cheaper kinds, either fibre alone or a mixture containing fibre. Certain laws, however, prohibit the use of shaving brushes using horsehair and all brushes using animal materials must be sterilized by approved methods.
(3) Painters' and Decorators' Brushes. (See BRUSHES, ART, below.) —Nearly all patterns of painting brushes are composed of three parts, the bristles or similar materials, ferrules—or other binding, and handles. In this class are sash tools, distemper and paint brushes, stock brushes, varnish brushes, etc. They may be either hand or machine-made.
(4) Artists' Brushes. (See below, and AIRBRUSH.) (5) Wire Brushes.—Using metal wire for the brush material, these include flue brushes, brushes for cleaning butchers' blocks and the steel surfaces of boilers, as well as castings in the foundry. These may be hand-drawn, staple set, or twisted-in-wire, or steelgript.
Maple and birch are chiefly used for the backs, galvanized steel wire for the twisted-in-wire handles and also different gauges of wire for filling the wooden handles or stocks.
(6) Other Kinds of Brushes.—Among the numerous other kinds of brushes are those made for special industries and those made for use in special machinery processes and known as machine brushes. Most industries use special brushes of some sort.