What type of fibers are used in fibreglass composites?

Fibreglass composites are primarily made using glass fibers, which are created by drawing molten glass into thin strands. This provides the composite material with several beneficial properties, including high strength, light weight, and resistance to corrosion. Glass fibers are ideal for use in construction, automotive, and aerospace applications because they offer a good balance between strength and flexibility, along with excellent insulating properties.

The other materials listed have different properties and applications. Carbon fibers are known for their high strength-to-weight ratio and are typically used in high-performance applications like sports equipment and aerospace but are not used in fibreglass composites. Wood fibers can add reinforcement to some materials but do not provide the same characteristics as glass fibers and are usually used in composite materials for different purposes, like in engineered wood products. Metal fibers could contribute strength in specific contexts but are not suitable for the structure or characteristics typical of fibreglass composites.