RE: making a mold
I have been sealing my high temp epoxy production molds with FMS then applying Frekote 700NC for around 15 years now and Frekote 44 many year prior to that, in both cases I have seen 100s of my tools yield as much as 300 to 500 production pre-preg parts processed at 260F and 350F before the necessity of manufacture new tooling. One of the things I learned over 30 years ago that causes premature epoxy tooling life is allowing razor knife cutting on the mold surfaces when utilizing pre-pregs or wet layup for that matter.
Bob