Plug

The moulds, mandrels, jigs and fixtures on and in which parts are laminated, formed and cured. Tooling material selection, from GRP and epoxy tooling board through to nickel alloy and steel, is driven by cure temperature, thermal expansion match, accuracy requirements and production volume.

A wax, semi-permanent polymer or film applied to tool surfaces so that cured parts release cleanly without damage to the part or the mould. Correct application routines are essential, and transfer of release agent onto surfaces intended for bonding or painting is a common cause of adhesion failures.

A pigmented, resin-rich surface coat applied to the mould face before laminating, which cures to form the smooth, weather-resistant outer surface of a GRP moulding. It protects the underlying laminate from moisture and UV exposure and provides the colour and gloss of the finished part.

The removal of a cured or solidified part from its mould, using wedges, compressed air or mechanical ejection. Poor demoulding practice is a major source of gel coat damage, mould wear and part distortion.