Connecting two ends of pneumatic tubing?

[artdutra04]

Pneumatic tubing with barbed connectors might work (such as on a prototype), but for your competition robot you will likely have more success using polycord.

Polycord, also known by the more generic names of round belting or urethane belting, is available in three types: hollow round, solid round, and flat belts. The hollow core version uses barbed connectors, and is generally not as durable as the solid or flat belt varieties. For the solid and flat belting, you use heat to melt and fuse the ends of the belt together.

Both round versions work on pulleys that have grooves in them to keep the belts aligned. The flat belt works on a pulley that (seemingly counter-intuitively at first glance) actually runs on a raised ridge. This ridge is actually what keeps the flat belt aligned and prevents it from "walking" down your pulley (the difference in tangential speed between the raised section and the lower section is what keeps the flat belt aligned on the raised ridge).

For fusing solid polycord, you can use a lighter or small torch to melt the ends of the cord (use the heat to melt, don't catch the polycord on fire), then press the two ends together using the inside of aluminum angle to keep the cords aligned.