This may sound trivial and many here may be already taking advantage of it, but if you need some very rigid, thin, hard insulation for an odd application Formica can be a useful substitute. When ever I am in H.D. I pick up one or two of the samples, they come in very useful for varied projects. It is made of a plastic laminate of paper or fabric with melamine resin. It was originally made for an electrical insulation to replace Mica. Something to add to the junk drawer. Max.