Theraband dimension calculator
Flat bands made from high quality rubber, such as Thera Band Gold, are the key to high performance slingshots. A slingshot is nothing without a good band set. Commercially available bands leave a lot to be desired, they are mass production products, often with poor performance.
It is not hard to make your own flat bands from Thera Band Gold, which you can easily find on ebay and in many orthopedic stores. First, you need to figure out the band dimensions that suit YOUR needs. You can use this calculator!
Note that it has boundaries, no band set with a draw of more than 18kg and less than 2 kg (within the practical limits). A heavier draw can only be managed by trained athletes, and super heavy ammo would be needed to match that kind of a draw.
After you have figured out your desired band dimensions, you can start making your own bands. You can download a free manual (pdf format), written by Jörg Sprave, here:
Band Dimensions Manual