This is basically an extension of the wet lay-up process where pressure is applied to the laminate once laid-up in order to improve its consolidation. This is achieved by sealing a plastic film or bag over the wet laid-up laminate and onto the tool / mold. The air under the bag is extracted by vacuum pump and up to one atmosphere of pressure can be applied to the laminate. This compression under the vacuum helps remove air, voids, and excess gas giving off during curing. To get the optimal properties out of carbon fiber parts made by hand lay-up or wet lay-up, most must be cured by a combination of heat, pressure, and or vacuum.