Fibreglass, (also called fibreglass and glass fibre), is the name given to the material that is made from extremely fine fibres of glass. Several polymer products use fibreglass as a reinforcing agent; fibre glass is also known as fibre-reinforced polymer (FRP) or glass-reinforced plastic (GRP).The invention of finer machine tooling worked wonders for glassmakers unable to cope with its increasing demand. The invention of the modern ‘fibreglass’ could be attributed to Russell Games Slayter of Owens-Corning. He wanted to use it for insulation. The trademark ‘Fiberglas’ has stuck with the product ever since.

Fibreglass has since found numerous applications in almost all walks of life. It stepped into the world of plastics when fibreglass moulding came into being. This is the process where reinforced resin plastics are formed into useful shapes. The process begins when a mould is first made using a plug or buck. It represents the original part to be copied. The plug must be waxed with some mould release wax to ensure a smooth separation of the mould and the fibreglass. PVA (Poly Vinyl Acetate) may be sprayed on as an additional mould release agent depending on the surface that is desired at the end although this reduces the smoothness of the moulds finally arrived at.

Once the release wax is applied to the plug, the plug is sprayed with gel-coat. Gel-coat is a pigmented resin without reinforcement. A harder and more durable finish would warrant the use of gel-coat.

The mould and the fibreglass are usually the same material, with the difference that the mould should be 5 times thicker than the fibreglass. For instance, if a part is made from two layers of 1.5 ounce mat, the mould should be 10 layers of 1.5 ounce mat.

Once the final layers of fibreglass are applied to the mould and allowed to set up, wedges are driven between the plug and the mould. They are then separated into two.