Figure 7-51.  Fabric impregnation with a brush or squeegee: A) wet layup materials; B) fabric placement; C) fabric impregnation; D)  squeegee used to thoroughly wet the fabric. 7.  Pour the resin onto the fabric. The resin should be a  continuous pool in the center area of the fabric. 8.  Put vacuum probes on the edge breather. 9.  Place a second piece of solid parting film over the  fabric. This film should be the same size or larger  than the first piece. 10. Place and seal the vacuum bag, and apply vacuum to  the bag. 11. Allow 2 minutes for the air to be removed from the  fabric. 12. Sweep the resin into the fabric with a squeegee.  Slowly sweep the resin from the center to the edge of  the fabric. The resin should be uniformly distributed  over all of the fabric.  13. Remove the fabric and cut the repair plies. Vacuum Bagging Techniques Single Side Vacuum Bagging Envelope Bagging Vacuum bag molding is a process in which the layup is cured  under pressure generated by drawing a vacuum in the space  between the layup and a flexible sheet placed over it and  sealed at the edges. In the vacuum bag molding process, the  plies are generally placed in the mold by hand layup using  prepreg or wet layup. High-flow resins are preferred for  vacuum bag molding. This is the preferred method if the repair part is large enough  for a vacuum bag on one side of the repair. The vacuum bag  is taped in place with tacky tape and a vacuum port is placed  through the bag to create the vacuum. Envelope bagging is a process in which the part to be repaired  is completely enclosed in a vacuum bag or the bag is wrapped  around the end of the component to obtain an adequate seal. It  is frequently used for removable aircraft parts, such as flight  controls, access panels, etc., and when a part’s geometry  and/or the repair location makes it very difficult to properly  vacuum bag and seal the area in a vacuum. In some cases, a  part may be too small to allow installation of a single-side  7-31