The most common and efficient way to manufature fibreglass is using what is known as the female moulding process.
To Start Process
A replica of what the end product will be needs to be made (the plug).
The Gelcoat (colour) is applied and left to cure (approximately four hours). A layer of fibreglass is then applied and left overnight. Depending on the thickness of the product the following day or days it will be completed.
Once the plug is perfect a mould is made. The mould has release agents applied and the end product can then be made off this mould.
Once the product is cured, it is de-moulded and the process can be repeated.