The humble tennis ball is one of the most iconic elements of this noble ball game, even the most disinterested individual would be able to instantly recognise a tennis ball no matter how much they try to avoid tennis itself. Although these ubiquitous balls are now an integral element of a tennis match, along with a tennis racket, they havent always been this way. Until the late 1800s tennis balls were made out of hand-woven leather, which was then stuffed with rags and horsehair. It was only after the 1870s that they began to resemble the vulcanised rubber balls that we are familiar with today. But how are items of tennis equipment such as tennis balls actually made? Lets take a closer look!
All tennis balls, whether they will end up on the most famous courts in the world or used in a back garden or park, start life as equals. They are all made from a large rubber sheet. These sheets are fed through special machines, which stamp out pre-measured slugs. These slugs are then melted and poured into half-shell moulds; its in these moulds that the liquidised blobs of rubber begin to form the tennis balls that we all recognise.
Before they can become a single tennis ball, the half-shells need to be carefully secured together, so they are dropped into a tray whereby glue is applied to the rim of each. The glues shells go into a press which forms them into a perfect sphere shape known as a core, and secures them so that the shells dont fall apart when they are hit on impact. The pressurised middle of the tennis ball occurs in the press, it is the press that regulates the pressure of air inside a ball and this is a very important step because pressure inside the ball determines its bounce levels.
At this stage, these balls still look like spheres of rubber, so they need to be finished off carefully to become usable and playable tennis balls. The tennis ball cores are sent through another machine that scuffs the surface before being covered in glue. After a glue soaking, they are wrapped with carefully shaped strips of green felt (other colours are possible, it depends on the individual manufacturer of the balls) and then sent into a machine which presses them from every angle, ensuring that the felt is tightly secured. Once the finished balls meet and satisfy regulations and approvals, they are stamped with the logo of the brand that is manufacturing them before being dropped into sealed and pressurised cans to maintain specific levels of pressure inside them.