HAND LAY-UP PROCESS  
The most common application is the Hand lay-up process. It provides only one finished surface. The hand lay-up method involves placing the fibreglass reinforcement, in the form of chopped strand mat, onto the mould and applying the catalyzed resin by brush/roller. This method offers good control of materials, enabling controls of thickness and resin to glass ratio.

Hand Lay-Up Process

 Spray-Up Process

SPRAY-UP PROCESS  
Also used for low to medium volume production, spray-up moulding is used for similar products as hand lay-up, but allows for greater shape complexity. A chopper gun is used to deposit the chopped strand reinforcement and resin. This method is more operator dependant to get the desired result, but this is additionally monitored by the use of flow meters and scales for materials. Its advantage is that it is quicker and cheaper for production of large items, or large numbers. As size diminishes it becomes more wasteful due to overspray.

RTM Process

RTM PROCESS
The resin injection method is used where high production rates or specific criteria such as critical wall thickness or two moulded faces are required. RTM products require more expensive reinforcement, the resin pigment is an additional cost, there is considerable waste, and post-moulding trimming is always required to remove the flash. Open moulded products can be trimmed to size in the moulds.Reinforcement is placed in the bottom half of the mould. The mould is then closed and clamped and catalyzed resin is then pumped into the mould under pressure until the mould is filled.