At One Place

What is a Tennis ball made of?

What is a Tennis ball made of?
A pressurised hollow shell of vulcanised rubber, covered in a glued-on wool and nylon felt.

Rubber is slightly permeable to gas, so a pressurised ball leaks continuously through its own wall from the day it is made. That is the reason tennis balls are sold in pressurised cans: the can holds the same pressure as the inside of the ball, so the gradient is zero and the ball keeps until you open it. Once opened, a ball loses usable bounce in a few weeks whether or not it is played with. Pressureless balls avoid the problem with a much thicker rubber wall, which is heavier to hit and harder on the arm, so they are used for practice and ball machines rather than matches.

Component by component

Every material is a choice, and the third column is the constraint that drove it.
Part Material Why that material
core natural and synthetic rubber blend, vulcanised with sulfur Natural rubber gives the rebound; synthetic rubber and fillers make the wall thickness repeatable enough for the ball to bounce to a specified height.
internal pressure air, or air with added nitrogen, at roughly 12 psi above atmospheric The gas, not the rubber, provides most of the bounce — which is why a ball goes dead long before the felt wears out.
cover melton cloth: a woven wool and nylon felt, typically 40-60% wool Wool gives the fuzz that grips the strings and slows the ball through the air; nylon stops that fuzz shedding in two games.
seam rubber-based adhesive under the two dumbbell-shaped felt panels A glued seam keeps the surface continuous, so the ball does not develop a preferred axis and swerve.

Other sport and games objects

Common questions

What is a Tennis ball made of?
A pressurised hollow shell of vulcanised rubber, covered in a glued-on wool and nylon felt.
What is the core of a Tennis ball made of?
Natural and synthetic rubber blend, vulcanised with sulfur. Natural rubber gives the rebound; synthetic rubber and fillers make the wall thickness repeatable enough for the ball to bounce to a specified height.
What is the internal pressure of a Tennis ball made of?
Air, or air with added nitrogen, at roughly 12 psi above atmospheric. The gas, not the rubber, provides most of the bounce — which is why a ball goes dead long before the felt wears out.

Related pages

Sources

  1. Official vendor product documentation — At One Place

How these figures are compiled and checked