I have been seeing watch bands made with beads and safety pins and they just stretch. What would be a good choice of stringing material to use so the safety pin will not break it and it stretches.
Powercord® is an elastic cord that returns to its original shape after stretching. It is recommended to use the largest diameter cord that will fit through the holes on the beads for strength. Elastic cord by nature is not going to be as strong as beading wire, but with care should last a long time.
The surgeon's knot is recommended for finishing elastic cording as it works well to prevent the cording from slipping apart. Place a small amount of E-6000® Jewelry and Craft Adhesive onto the knot; this adhesive is flexible after drying as well as will keep the knot secure. The knot can then be hidden inside of a bead in the design or by placing a crimp cover over the knot.