A vacuum bag is a bag made of strong rubber-coated fabric, open at one end, and used to bond or laminate materials. The item to be laminated is placed inside the bag, the open end is sealed, and air is drawn out with a vacuum pump. As a result, uniform pressure approaching one atmosphere is applied to the surfaces of the object inside the bag, holding parts together while the adhesive cures. The entire bag may be placed in a temperature-controlled oven, oil bath or water bath and gently heated to accelerate curing. A laminate is a material constructed by uniting two or more layers of material together. ... A vacuum pump is a pump that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. ... When expressed as a measurement, an atmosphere (symbol: atm) or standard atmosphere is a unit of pressure roughly equal to the average atmospheric pressure at sea level on Earth. ...

Laminating of flat objects can be performed more efficiently in a heated laminating press, but when the objects are curved or have irregular shapes, a vacuum bag works better.