Manual method (Hand Lay-up)

The hand lay-up method, which some people call wet lay-up, is another method of making FRP composite, which is usually used to cover the external surface of structural members for strengthening.
In this method, a rigid mold is covered with resin and a roller is used to press the fibers (usually in the form of a sheet or raw fiber cloth) into the resin. In some cases, some additional resin is added to the outer surface of the fibers to ensure that the fibers are completely impregnated with the resin. Additional layers of FRP material can be added on top of each other to achieve the desired thickness. During the strengthening of the structure, for example, the strengthening of the structures of a concrete column, the mold used is the structural member that needs strengthening. The issue of quality control is very important in this method and sometimes skilled workers are needed.