Camber, rocker and the mould
Quotes are verbatim and attributed to their original authors.
The mould sets the camber and rocker of the ski, but the finished ski keeps only part of what the mould has — the layup springs back as it comes off. How much it keeps depends mostly on whether the cure is heated, so builders deliberately over-build the mould.
How much camber to build in
A heated press holds the mould's shape closely; a room-temperature cure loses roughly half.
A useful rule of thumb from a room-temperature builder: "If I shim the press to 8mm I would get about 4mm finished rise — kinda the same for camber" (rockaukum). Compare a few finished pressings against the mould you used and you will quickly learn your own shop's ratio.
A cure schedule that holds camber
Staging pressure and heat gives repeatable results:
Builders also note that a rapid run-up to high temperature can leave more camber than the mould, and that heating one side only shifts camber — see Ski press and the pressing notes for using differential top/bottom heat to tune it.
Rocker moulds
Rocker springs back more than camber, so moulds are over-cut and a stiff, layered core helps hold the shape better than glass alone:
That fibre-shortening is why a heavily rockered tip can show glass "bunching" waves — a reason some builders reach for a pre-cured top sheet of glass on full-rocker shapes.