Fiberglass Reinforced Pipe
Resin is mixed with a catalyst (e.g. Butanox LA) or hardener if working with epoxy, otherwise it will not cure (harden) for days / weeks.  Next, the mold is wetted out with the mixture.  The sheets of fiberglass are placed over the mold and rolled down into the mold using steel rollers.  The material must be securely attached to the mold, air must not be trapped in between the fiberglass and the mold.  Additional resin is applied and possibly additional sheets of fiberglass.  Rollers are used to make sure the resin is between all the layers, the glass is wetted throughout the entire thickness of the laminate, and any air pockets are removed.  The work must be done quickly enough to complete the job before the resin starts to cure.  Various curing times can be achieved by altering the amount of catalyst employed.