For what it’s worth, thermoplastic was available years ago (and most
likely still is) in sheets for use by orthotists and physical
therapists, who used it to make custom-molded splints and braces. I
mention this because this product may be more reasonably priced for
the health care industry than it is for jewelers (isn’t everything?) .
Back in the days when I was involved with this stuff, I remember it
being offered by a company called Fred Sammons, Inc.