The purpose of rubber bands is to bring the fingers back to the open position when the hand is at rest. To minimize the closing effort, they should exert as little tension as possible that will allow the fingers to open.
The various variations of the Phoenix hand use dental rubber bands except the Phoenix reborn hand which uses wire rubber bands. The Raptor and Raptor Reloaded hands also use wire rubber bands.
Dental elastics are very easy to put on and replace, but tire quickly and need to be replaced often. They are also difficult to find in some countries, and do not tolerate hot climates.
Corded rubber bands take a bit more work to put on, but they allow for fine tension adjustment and are available all over the world.
Dental elastic
Wire elasticFor all devices that do not use dental elastics (Raptor and Raptor reloaded, Phoenix reborn ...).
The rubber bands are found in haberdashery or in the manual work department, in 1mm or 2mm in diameter, and in different colors. Take 50cm per device, counting wide.
Wire elastics are recommended in hot countries and countries where it is difficult to obtain dental elastics.
Dental elastics
Dental elastics come in many diameters and strengths. They will be provided to you when you make hands for recipients. For your test hand get a 1/4 ″ diameter pouch in the greatest strength possible, ideally 6.5oz.
Place the rubber bands on the studs on the top of the fingers. The rubber bands touching the palm are in a circle, while the rubber bands touching the terminal phalanges are figure-eight (to prevent them from getting caught in the joint).
Wire elastics
Wire elastics are used in 1mm diameter for the majority of cases, exceptionally in 2mm for very large hands.
The elastics pass through channels on the top of the fingers, and are tied on the bridges at their ends. On the palm side they also pass through channels but are not tied, they simply come back to the next finger, connecting the fingers two by two. Except on the thumb which is tied to it at each end.
Putting on a rubber band can be the most frustrating experience, or the fastest.
The trick is to make a loop of nylon thread, which is much stiffer than the elastic, and to get this one by making the loop follow the reverse path of that desired by the elastic.
