WET LAY UP TECHNIQUE:
It is the simplest method, where continuous lengths of mats, fabrics or rovings are passed through a resin bath and through squeeze rolls. This process is used where material are required for immediate use or only in small or moderate quantities. The final product is usually quite tacky and somewhat difficult to handle especially when stored as rolls.
PREPEGS OR B-STAGED MATERIALS:
Here the fibers are drawn through a bath, squeeze rolls and then through one or more heating zones. In the heaters the laminate is stripped off solvents and other volatiles and then the resin is advanced to the B-stage so that relatively dry and only slightly tacky material results. The degree of B-staging achieved is a function of the temperature, speed of travel, resin content, and the resin type.
This process is used for laminates to be cured at high temperature or by UV radiation and usually result in material having relatively long shelf lives and can be easily handled and stored. The final product is known as a pre impregnated fabric or roving.