By this machine technology cut roving and initiated resin are simultaneously applied by special pneumatic gun onto the mould.

The gun is mostly hand-guided, but it is possible to use PC controlled automation.

The moulds are simple, low-cost, practically the same as for hand lay-up, mostly made of composites.

Gelcoat is usually applied (by hand or by spraying) as a first layer. Laminate spray-up is carried out in several layers “wet-to-wet” depending on the part thickness. Each of applied layers is con-

solidated by fin, paddle or bristle rollers of various size and shape removing the entrapped air bubbles at the same time.

Spray-up (SU) ranks also among so called “open” technologies, therefore it is necessary to carry out it in separate air exhausted spraying boxes as the mostly used resins by spray-up are polyesters containing harmful styrene.