Method of Inspection Disbond Delamination Dent Hole Crack Water Ingestion Overheat and Burns Lightning Strike X (1) X (1) X X X (2) X (3) X (3) X (1) X (1) X X X X (2) X (3) X (3) X X X X X (1) X (4) X (4) X X X X Visual X-Ray Ultrasonic TTU Ultrasonic pulse echo Ultrasonic bondtester Tap test Infrared thermography Dye penetrant Eddy current Shearography Type of Defect Notes:  (1) For defects that open to the surface (2) For thin structure (3 plies or less) (3) The procedures for this type of inspection are being developed (4) This procedure is not recommended Figure 7-30.  Comparison of NDI testing equipment. Figure 7-32.  Air tools used for composite repair. Figure 7-31.  Hand tools for layup. Caul Plate  Support Tooling and Molds A caul plate made from aluminum is often used to support the  part during the cure cycle. A mold release agent, or parting  film, is applied to the caul plate so that the part does not attach  to the caul plate. A thin caul plate is also used on top of the  repair when a heat bonder is used. The caul plate provides a  more uniform heated area and it leaves a smoother finish of  the composite laminate. Certain repairs require tools to support the part and/or maintain  surface contour during cure. A variety of materials can be used  to manufacture these tools. The type of material depends on the  type of repair, cure temperature, and whether it is a temporary  or permanent tool. Support tooling is necessary for oven and  autoclave cure due to the high cure temperature. The parts  deform if support tooling is not used. There are many types  of tooling material available. Some are molded to a specific  part contour and others are used as rigid supports to maintain  the contour during cure. Plaster is an inexpensive and easy  material for contour tooling. It can be filled with fiberglass,  hemp, or other material. Plaster is not very durable, but can be  used for temporary tools. Often, a layer of fiberglass-reinforced  epoxy is placed on the tool side surface to improve the finish  quality. Tooling resins are used to impregnate fiberglass,  carbon fiber, or other reinforcements to make permanent  tools. Complex parts are made from metal or high-temperature  tooling boards that are machined with 5-axis CNC equipment  to make master tools that can be used to fabricate aircraft parts.  [Figures 7-33  and  7-34] 7-20