188 Section 2 Nonstructural Repairs Copyright Goodheart-Willcox Co., Inc. Edge Alignment Edges of doors or fenders can be pushed in during an impact. Figure 9-30 shows a fender edge that has been pushed inward relative to the door. A slide hammer can be used to pull out the fender edge. An L-shaped attachment is placed along the edge of the fender. Tapping with the slide hammer, as shown in Figure 9-31, will raise the edge of the fender so it is flush with the door. Note that there is no buckle to remove in this example. The door in Figure 9-32 has been pushed in and has buckled. The edge of the door consists of three layers of metal: the inner structure, the inner hem flange, and the outer hem flange. Therefore, the edge of the door can be quite stiff when buckles form. To remove the damage, the edge should be raised as the buckle is worked. An L-shaped attachment is placed on the damaged edge. As one technician uses the slide hammer to remove the damage, another technician taps on the buckle. This task can be accomplished by one technician. Instead of slide hammering, the technician can pull on the shaft of the slide hammer while tapping the buckle. Removing the door is another method of repair. Locking pliers may be used to align the edge of the door. Pulling up on the locking pliers bends the edge of the door. A hammer is used to tap on the buckle at the rear off the edge. The low area behind the buckle can be raised with draw pins. Figure 9-33 shows a dolly to tap up the door edge. Shrinking Shrinking reduces the surface area of stretched metal. Shrinking can also remove false stretch. One way to reduce the stretched metal’s surface area is to apply heat. Heat, even the small amount generated by a draw pin welder or grinder, will cause the stretched metal grains to thicken. The thickening causes a reduc- tion in surface area, thereby eliminating the stretch. The amount of metal shrinkage that occurs depends on the size of the heated area and the heating tempera- ture. The heating process must be carefully controlled. Stretch damage most commonly occurs on low-crown panels. Uncontrolled use of heat on a low-crown panel will cause warp damage. Warp damage is a group of high and low areas in a panel. Warp damage is difficult to remove, if not impossible. Always use the minimum amount of heat required when shrinking. Goodheart-Willcox Publisher Figure 9-30. This fender was driven back and under the lip of the door by a front impact. Opening the door would damage the fender. Goodheart-Willcox Publisher Figure 9-31. When using a slide hammer to move a fender edge, line up the hook at the body line. Goodheart-Willcox Publisher Figure 9-32. The edge of this door has been pushed in and has buckled. Buckles