Before the Civil War, billiard balls were almost exclusively made from ivory. However, the need was greater than the resource; as the demand for ivory dramatically rose, the supply dwindled. With a shortage of ivory rapidly approaching, a U.S. manufacturer offered $10,000 reward to the person who could come up with a new way to manufacture the billiard ball. John Wesley Hyatt, an engineer from New York, along with his brother Isaiah Smith Hyatt, created celluloid, a material that was similar to ivory that could be carved and shaped. However, celluloid was not able to be molded.
Billiard Ball Material
Since then, the manufacturing of billiard balls has seen many improvements. A billiard ball is now made out of unsaturated polyester resins and calcium carbonate reacted with an organic peroxide catalyst. The ball is formed by a technique known as cast resin, the act of molding these materials in a vacuum chamber. Air that is in the mold is taken out by the vacuuming process, allowing the parts of the ball to come together.
The ball has two parts, a major portion and a minor portion. The minor portion is interlocked with the major portion at the minor portion's surface. This is done by creating two different surfaces, pointing in different directions, making sure that the surfaces are angled toward each other. After this is done, the ball is taken out of its mold, which cools it, causing the major portion to shrink, filling in the connection completely.
This process eliminates the possibility of a faulty ball. The ball is perfectly spherical, with no air inside to create weight discrepancy. The weight of the ball is evenly distributed due to the air being removed, as well as the continuity of the adhesion of the two sections. The addition of dye in the process manufactures a complete set of billiard balls.