Embedding small objects in resin.

A polyester resin, dissolved in styrene, is hardened by mixing with a catalyst. The resin is often used with glass-fibre reinforcement to give glass-reinforced plastic (GRP). Small scale repair kits use similar materials but with the catalyst supplied as a paste.

This wide range of epoxy adhesives and polyester resins is produced mostly as two-component systems. Curing is effected by the reactions of a resin and a hardener.

This guide explains how to use three of the common composite casting materials, used in schools.