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.
Manufacturing
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.
Results
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.