What Are Foam Balls Made Of?

Foam balls come in a variety of sizes and shapes. There are two primary types of foam used to make foam balls. These types of foam are different in terms of density and weight, so each can be used to make foam balls for different purposes.

Materials

Foam stress balls and athletic foam balls are usually made from polyurethane, which produces a heavy, resilient ball. Foam balls used for arts and crafts are usually made from extruded polystyrene to make lighter, more porous foam balls that can be cut and shaped easily. Other materials are sometimes used when different properties such as weight, roughness or density are required, but polyurethane and polystyrene are by far the most common.

Coating

People use foam balls for athletic purposes on different surfaces and at different levels of intensity. Even relatively durable foam can sustain damage and wear away over time. For this reason, foam balls used in sports are often coated with tougher substances, such as rubber or vinyl.

Shapes

Most foam balls are spherical, but this is not always the case. They may be oval, if the activity or art project calls for an oval. For example, an athletic equipment company would never try to sell a spherical foam football. The shape of the ball does not affect the material that it is made from, and vice versa.

References

• Polyurethanes: Frequently asked questions on polyurethanes
• The Foam Factory: Closed Cell Foam