This page explains the basics of vacuum bagging. Vacuum bagging is used to remove the voids and air pockets from a multilayer composite layup, and to remove the excess epoxy. This technique helps to ensure a strong and lightweight finished product. In the drawing below, the nylon bleeder fabric allows the epoxy resin to soak into the breather fabric when the layup is vacuumed together. The part is bagged and sealed, and the vacuum pump is run at least until the part has partially cured. Heating the part to around 100 degrees F will accelerate the curing. The nylon fabric, also known as "peel ply" peels easily off of the molded part after curing. care must be taken to keep the epoxy out of the vacuum pump.