How rubber bands are made
A rubber band is a slice of a long rubber tube, which is why it has no seam.
- stations
- 6
- things upstream
- 2
- raw sources
- 2
- step from the ground
- 1
The short version
Rubber arrives at the factory in big bales and is pushed out through a die as a long hollow tube. The tube is slid onto metal rods, heated until the rubber cures, and then sliced across its width. Each slice is a closed loop, so the width of the cut sets how wide the band is and the tube sets how long.
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Break down the bale
Natural or synthetic rubber comes in large bales. Most bands use natural rubber because it stretches better than the synthetic kind. The raw gum is softened and sulfur is worked in, ready for curing later.
Goes in -
Push out a long tube
The softened rubber is forced through a ring-shaped die and comes out as a hollow tube. The thickness of the tube wall decides how strong the finished band will be.
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Slide tubes onto rods
Lengths of tube are fed onto metal rods called mandrels. The rod holds the tube round while it is heated, and its circumference becomes the length of the band.
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Cure the rubber
Heat links the rubber molecules together so the band springs back after stretching. Before this step the tube is soft and would stay stretched.
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Slice across the tube
Blades chop across the cured tube like a baker slicing a sausage. Every slice falls away as a closed loop with no joint. Slices set closer together make narrower bands.
sized by flat length, cut width and wall thickness
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Sort by size number
Bands are sorted and packed under industry size numbers. Lower numbers are narrower, and the numbering restarts for the longest bands.
Worth repeating
- Warm a stretched rubber band and it pulls shorter, which is the opposite of what a metal wire does.
- A rubber band gives off a little heat as you stretch it and soaks heat up as it relaxes, so it can cool its surroundings slightly.
- The first rubber band patent was granted in England in 1845 to Stephen Perry.
Back to the ground
Follow every input upstream and rubber band starts as these 2 raw sources.
Open the whole family tree
Keep walking
Sources
Cite this page: "How rubber bands are made." Assembly Line, 2026-11-03. https://assemblyline.org/make/rubber-band