How tennis balls are made
A new tennis ball is pressurized, and it begins to go flat the moment its can is opened.
- stations
- 8
- things upstream
- 36
- raw sources
- 10
- steps from the ground
- 8
The short version
A tennis ball is a hollow rubber core covered in felt. Two rubber half-shells are molded and glued into a sphere, which is pressurized with gas. A woven felt of wool, nylon and cotton is glued round the core. The finished balls are sealed in pressurized cans so they keep their bounce.
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Mix the rubber
Rubber is blended with fillers and chemicals into a stiff dough, which is cut into small pieces, one for each half-shell.
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Press the half-shells
Each piece is pressed in a heated mold into a cup shape and cured.
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Glue the halves together
Two cups are cemented rim to rim into a hollow sphere. Gas is sealed in at about 12 psi above the surrounding air pressure.
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Weave the felt
The felt blends wool, nylon and cotton. Its surface slows the air flowing round the ball, which reduces drag.
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Cut the felt dumbbells
Presses punch the felt into dumbbell-shaped pieces, two per ball. Their edges meet in the curved seam you see on a ball.
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Glue on the felt
Cement is brushed on the core and the two felt pieces are pressed around it.
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Fluff and steam
Steam and brushing raise the nap of the felt so the ball looks fuzzy and new.
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Seal in pressurized cans
Balls are packed under pressure matching their own, which keeps the air inside from escaping until the can is opened.
Worth repeating
- Tennis balls were white or black until 1972, when the ITF introduced yellow ones because they were easier to see on television.
- Wimbledon kept using white balls until 1986.
- In 1480 King Louis XI of France banned filling tennis balls with chalk, sand, sawdust or earth.
Back to the ground
Follow every input upstream and tennis ball starts as these 10 raw sources.
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Sources
Cite this page: "How tennis balls are made." Assembly Line, 2026-11-03. https://assemblyline.org/make/tennis-ball