Spray-up is a manufacturing process used primarily in the production of composite materials. It involves spraying a mixture of resin and reinforcing fibers onto a mold to create a solid structure. This method is often used for making large parts, such as boat hulls or automotive components, due to its efficiency and ability to cover complex shapes. The process typically uses a spray gun that combines the resin and fibers, allowing for a quick application. Once the material is applied, it cures to form a strong, lightweight product. Composite materials produced through spray-up are known for their durability and resistance to environmental factors.