Then the sheeting goes onto the cores and the cores get placed into the shucks with some 1 mil plastic between the sheeting and the shucks. This is done so that if there is any epoxy bleed through it will not glue the shucks to the sheeting. The whole deal then goes into a vacuum bag with paper towel used as breather material. When vacuum bagging, breather is nesessary to get consistent pull over the entire surface. I pull about 5" HG in the bag and let them cure for the next 12 hours under vacuum. 24 hours would make me feel better but unfortunately I am building in the house these days due to a lack of having a garage. I just can't have the pump going off in the middle of the night while we are sleeping.