I couldn't quite get the hang of tying a double fisherman's knot on the bungee shock cord of my Regulator Necklace so I designed these slip clasp and used a regular knot.
Printed with TPE 90A, 0.3mm nozzle, 0.2mm layer height at 30mm/s, 245 Deg C on the hotend, 60 Deg C on the bed, solid infill.
I print TPE on Poly-carbonate that has been sanded with 220 grit sandpaper. I find it adheres rather well.
The slip clasp are designed for a 3/16" bungee shock cord.
I cut off about 85cm, singed both ends with a mini torch to keep them from fraying, looped them around and tied a regular knot and then just pulled tight till the knot seated into the clasp.
GeeeTech Prusa i3 Aluminum
Spool3D TPE 90A