I wanted the jaw to hinge. I used what I had in my craft room. Chicago screws (aka as sex screws, barrel nuts, barrel bolts) and plastic from a bit of plastic tubing. I cut the tubing in to a 2cm bit then I cut it open, so i could splay it out. I took a heat gun to it and flattened it. This let me make plastic type washers to go between the screw/nut and the foam, so the screw/nut didnt just get pulled through the foam. I've displayed the arrangement I made on the cutting mat. It goes from outside in, screw, plastic washer, plastic tube, plastic washer and then bolt. The plastic tube is there to protect the foam from any bits of thread that are exposed from the screw.
Made from 10mm foam floor mats, 5mm anti-fatigue foam floor matting and 2mm craft foam. Its all glued together with Silka's contact adhesive.