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What is a Bowling ball made of?

What is a Bowling ball made of?
A dense shaped weight block inside a filler, wrapped in a polyester, urethane or reactive resin coverstock.

Almost everything interesting about a modern bowling ball is invisible. Lanes are dressed with oil in a pattern that is heavier in the middle than at the edges, so the ball skids through the oil, grips the dry back end and hooks. The coverstock decides when that grip happens and the internal weight block decides how violently the ball changes direction once it does. Serious bowlers re-sand or polish the cover as it absorbs lane oil, and the ball is periodically baked to draw oil back out of the pores.

Component by component

Every material is a choice, and the third column is the constraint that drove it.
Part Material Why that material
weight block dense resin loaded with barium or bismuth, moulded into a deliberate asymmetric shape The block's shape, not the surface, sets how early and how hard the ball hooks — it moves the centre of mass off the geometric centre.
filler lower-density polyester or urethane resin It brings the ball up to the legal 27 in circumference at the chosen weight without disturbing the weight block's effect.
coverstock polyester (plastic), urethane, or reactive resin urethane Reactive resin is porous at a microscopic scale and grips oiled lane surfaces; plastic slides straight and is used for spares and house balls.
finish sanded or polished surface, from about 500 to 4000 grit Surface roughness decides where on the lane the ball starts to grip, and is the cheapest thing a bowler can change.

Other sport and games objects

Common questions

What is a Bowling ball made of?
A dense shaped weight block inside a filler, wrapped in a polyester, urethane or reactive resin coverstock.
What is the weight block of a Bowling ball made of?
Dense resin loaded with barium or bismuth, moulded into a deliberate asymmetric shape. The block's shape, not the surface, sets how early and how hard the ball hooks — it moves the centre of mass off the geometric centre.
What is the filler of a Bowling ball made of?
Lower-density polyester or urethane resin. It brings the ball up to the legal 27 in circumference at the chosen weight without disturbing the weight block's effect.

Related pages

Sources

  1. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked