Hand layup, a traditional yet versatile technique in composite manufacturing, involves the manual application of layers of reinforcement materials, such as fiberglass, onto a mold, followed by the saturation of these layers with unsaturated polyester resin (UPR). This method allows for precise control over the orientation and thickness of the reinforcement, making it suitable for producing parts with varying complexities and specifications. UPR, known for its excellent wetting properties and compatibility with fiberglass, acts as a binder, effectively bonding the layers of reinforcement together to form a strong and durable composite structure. While hand layup may require skilled craftsmanship and longer production times compared to automated processes, it remains a preferred method for fabricating custom or low-volume parts across industries such as marine, automotive, and wind energy, where specific performance requirements and design flexibility are paramount.