Thread works for lightweight objects, if the surfaces won't abrade the thread, and if the thread won't cut through the surfaces.
Mylar-D is an alternative that works like thread, but it is abrasion-resistant, much stronger, and has less tendency to cut into surfaces. Use straps cut 1/16" to 1/4" wide, depending on weight to be supported. Mylar-D is extremely strong and will not stretch like monofilament; a couple of 1/4" straps will easily support a handgun or a large knife, so a lace fan should be a breeze.
The important thing is to secure the clear film straps' ends on the back of the mount board so they can't slip. There's a secret method for that, which was to be revealed in the Atlanta class.
Thanks for the class plug, Marc. Yes, "The Complete Guide to Shadowboxes and Object Framing" is expected to be on the January Las Vegas schedule, and Marc Lizer has a role in it. Someone has to be there to keep me in line and, believe it or not, he's it.
Y'all come.