Five rubber bands

Manufacturing

The manufacturing process involves extruding the rubber into a long tube to provide its general shape, putting the tubes on mandrels and curing the rubber with heat, and then slicing it along the width of the tube into little bands.^[1][2] While other rubber products may use synthetic rubber, rubber bands are still primarily manufactured using natural rubber because of its superior elasticity.

Rubber Band Sizes

Measuring

Measuring a rubber band

A rubber band's length is half its circumference. Its thickness is the distance from the inner circle to the outer circle.

Lay a rubber band down so that it makes a square. The band's width is the height of that band. If one imagines a rubber band in manufacture, that is, a long tube of rubber on a mandrel, before it is sliced into rubber bands, the band's width is how far apart the slices are cut.

Rubber Band Size Numbers

A rubber band is given a [quasi-]standard number based on its dimensions.

Generally, rubber bands are numbered from small to large, width first. Thus, rubber bands numbered 8-19 are all 1/16 inches wide, with length going from 7/8 inches to 3 1/2 inches. Rubber band numbers 30-34 are for width of 1/8 inches, going again from shorter to longer. For even longer bands, the numbering starts over for numbers above 100, again starting at width 1/16 inches.

The origin of these size numbers is not clear and there appears to be some conflict in the "standard" numbers. For example, one distributor^[3] has a size 117 being 1/16 inch wide and a size 127 being 1/8 inch wide. However, an OfficeMax size 117^[4] is 1/8 inch wide. A manufacturer^[5] has a size 117A (1/16 inch wide) and a 117B (1/8 inch wide). Another distributor^[6] calls them 7AA (1/16 inch wide) and 7A (1/8 inch wide) (but labels them as specialty bands).

References

Rubber bands and heat - http://scifun.chem.wisc.edu/HOMEEXPTS/rubberband.html

External links

• The Unofficial Rubber Band Website
• http://www.madehow.com/Volume-1/Rubber-Band.html

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