Learn how to build a waterproof fibreglass box using chopped strand matting and polyester resin and Gelcoat. This method can be used to construct composite storage tanks, pools and anything they requires a solid water tight construction. With the right materials and techniques, you can create fiberglass box solutions that not only look great but also provide excellent functionality. In this comprehensive guide, we will detail the process of manufacturing fiberglass parts, covering everything from material selection. Here's a couple of low cost and quick procedures I use to manufacture simple parts using fiberglass and carbon fiber.