In the wet lay-up process, the fibers are positioned in the mould dry and the resin is applied with a brush. The resin is mixed by hand and mistakes can be made during mixing. This is a relatively inexpensive process, but normally the part is heavier and the fibers can distort during the lamination process meaning the process is less controlled. This method does not lend itself to the Autoclave process which cures the part under controlled heat and pressure.
In the Prepreg process used to manufacture BST wheels, the resin is applied by machine onto the fibers in a thin film. Therefore, the resin is very even and controlled. The parts are then cured under a high pressure and temperature environment (Autoclave). This results in a well-compacted laminate with better properties than with wet lay-up. Laminate properties in Prepreg Carbon fiber can be 10%- 20% better than wet lay-up at a lower weight (because less resin is used to do the same job). This Prepreg and Autoclave process is used to manufacture the exceedingly strong, but light, chassis centres (often known as ‘tubs’) for Formula 1 race cars.