Another of the advanced components that might catch you by surprise when you are more familiar with dealing with Minecraft style elements. Fiberglass is one of the more advanced crafting components that you need to create later on in the game using components that are much more expensive and rare to come across.
Where to find Fiberglass
Fiberglass is crafted at the factory building. This is a building that you must use a skill point to unlock under the manufacturing skill area. Once constructed you will be able to construct fiberglass once you have some plastic. This means you will also need oil.