They are very easily dyed, and are often made to resemble the cloth upon which they are to be worn. Over 50,000,000 pounds of tagua nuts are imported into the United States each year. The chief cen ters of this manufacture are Rochester, N. Y., and Newark, N. J. ; about 10,000 people are employed in the factories. The ivory buttons are purchased in large quantities by the clothing trade for use on men's and boys' coats, vests, trousers, and overcoats, and on women's suits and coats.
A large proportion of the manufacturers of metal buttons receive their metal prepared in sheets ready for cutting into blanks. Power presses cut blanks for fronts and backs. Patterns are then stamped on them and the buttons are assembled and polished.
There are also cast-metal buttons made by pouring molten metal into molds of different sizes and designs.
Various patent buttons are made which do not have to be sewed on. They are usually in two pieces, with a shank on one piece which goes through the cloth and fastens by means of a spring clip in the other half on the other side of the cloth.
Bone buttons are made from the shin bones of cattle. In the United States the packing houses furnish the great bulk of the material used in their manufacture. They are used mainly for underwear, waists, and children's clothing. Cloth and silk but tons are made by covering wooden forms or metal discs. The work of cov ering is now done by machinery.
Glass buttons are made in infinite variety and color, and there is no limit to the patterns that can be produced. They are chiefly of the novelty type, and the nearest to a standard is the jet glass button. Bohemia has been the home of the glass button industry for many generations, and the skilled workmen guard the secrets of the trade, which have been handed down from father to son ever since the industry was started.
The ordinary shoe button is made of papier-mâché.
In the process of manufacture the buttons are satu rated with linseed oil or amber varnish, to give greater firmness; they are then dried, again coated with hot amber varnish, and baked. In finishing they are polished with pumice, given the desired coating of color, dried and again coated ; and this process is repeated for three or more coats.