The semi-finished fibres (fabric/layers/fibre mats) are placed by hand in a mould and are wetted with resin (matrix). Afterwards the fibres are aired by pressing them with a roller so the air entrapped in the laminate and any resin surplus is removed. This process is repeated several times until the desired layer thickness is reached. This method is also known as wet-in-wet process.
When all layers have been put in, the component part will cure by the chemical reaction of resin and hardener. Hand lay-up does not require any special tooling and is suitable even for very big component parts. It is often applied for the production of serial parts, which shall be lightweight and inexpensive at the same time.
This moulding method offers low tooling costs. On the other hand, the component part is of inferior quality due to low fibre content and a lot of manual work is required which must be done only by skilled laminaters. Furthermore, the health and safety of the workers operating with the resin material must be guaranteed.