I must have missed this back in 2012. I have made hundreds of acrylic puzzles, with multiple layers of 1/8" usually black and clear. I cut some clear 2mm adhesive vinyl to the total thickness, and wrap it around the edges. You cannot really tell it's there and holds all layers together nicely without any glues. I cut with the plotter, but you can use a metal ruler and Olfa or Xacto.
Sammamish, WA
Epilog Legend 24TT 45W, had a sign business for 17 years, now just doing laser work on the side.
"One only needs two tools in life: WD-40 to make things go, and duct tape to make them stop." G. Weilacher
"The handyman's secret weapon - Duct Tape" R. Green