I was short of a 3 metre USB lead, I had several 1.5 / 1.8 metre leads as simply joining them was not a very secure method as this was to be a permanent connection. Wrapping "duck tape" was an option but that usually turns messy after a while I then cameup with the idea of using heat shrink tube, the method is very simple with the finished lead as shown.
1) Select the appropriate size of Heat Shrink Tube (Normal shrink ratio is 2:1) [sorry granny]
2) Cut to length so it sits just over the shoulders of both connectors
3) Fit over the join an apply heat from a heat gun or hair dryer until the tube shrinks
4) Job done, have a beer.