Chopped strands

A non woven glass reinforcement made from chopped strands distributed randomly and held with a powder or emulsion binder that dissolves in styrene based resins. It gives roughly equal in plane properties in all directions, wets out readily by hand lay up and is the standard reinforcement in GRP flat roofing laminates. It is specified by areal weight.

A thin surface treatment applied to fibres during manufacture, typically containing film formers, coupling agents such as silanes, and processing aids. It protects the filaments during handling and, critically, controls adhesion and compatibility between the fibre and the matrix resin, so it must be matched to the resin system in use.

A dough-like moulding compound of short chopped fibres, filler and thermosetting resin, shaped by compression or injection moulding. BMC suits complex, detailed parts such as electrical housings, reflectors and valve components.

An open-mould process in which chopped glass fibre and catalysed resin are sprayed simultaneously onto a mould surface and then compacted with rollers. It is faster than hand lay-up and suits large parts, but gives less consistent fibre content and laminate thickness.