Fiberglass spray lay-up process

Spray-Up also known as chop method of creating fiberglass objects by spraying short strands of glass out of a pneumatic gun.

Spray-up is an open-moulding composites fabrication process where resin and reinforcements are sprayed onto a reusable mould.

The resin and glass may be applied separately or simultaneously "chopped" in a combined stream from a chopper gun.

Bathtubs, swimming pools, boat hulls, storage tanks, duct and air handling equipment, and furniture components are some of the commercial uses of this process.

The basic reinforcement material for this process is glass-fibre rovings, which are chopped to a length of 10 to 40 mm and then applied on the mould.

In the boating industry, a single-sided female mould made from FRP (fibre-reinforced plastic) is used to make yacht hulls.

Once the gelcoat hardens, a spray gun is used to deposit the fibre resin mixture onto the surface of the mould.

Once the material is sprayed on the mould, brushes or rollers are used to remove entrapped air as well as to ensure good fiber wetting.

Fabric layers or continuous strand mats are added into the laminate, depending on performance requirements.