I think some people use non-stick baking-paper to stop the beam from sticking to the epoxy.
Or that green PVA mold release spray
Or cooking spray (tradename PAM)
Or carnuba car wax
I think I may have used Rain-X in a bind once for a rudder repair.. If I'd only have used Jake's hotel key-card idea....
your options are pretty open as long as it doesn't bind to the epoxy...