205 Chapter 9 Nonstructural Panel Repair Copyright Goodheart-Willcox Co., Inc. Hail Dent Figure 9-65 shows a heat gun in use to warm a hail dent in an aluminum hood. The back of the panel has been checked for adhesive before heating. Move the heat gun in a circle around the edge of the dent and work to the center. Monitor the heat to stay below 400° F. When the dent reaches 400° F, remove the heat. Watch the dent to see if it raises. If the dent remains, heat again. If two heatings do not raise the dent, use the following method. Dent A larger dent is shown in Figure 9-66. The back side of the panel was first checked for adhesives, and none were found. The paint is removed by sanding with 80-grit paper. Studs are welded into the deepest part of the dent. The bridge spans the damage and hooks to the studs. Slight upward pressure is applied by the technician. As the aluminum is heated to 400° F, more upward pressure is applied with the bridge. A straightedge is used to check that the low area has been raised. When the low area is at proper contour, the perimeter of the dent is lightly tapped with a body hammer. Goodheart-Willcox Publisher Figure 9-64. Aluminum can crack due to work hardening. The damaged area on this hood was heated before the clamp was tightened to minimize the possibility of cracking. Aluminum hood Goodheart-Willcox Publisher Figure 9-65. Move the heat gun in a circle around the edge of the dent and work toward the center. Monitor the heat to stay below 400° F. When the dent reaches 400° F, remove the heat. Heat gun Goodheart-Willcox Publisher Figure 9-66. The bridge spans the damage and the lever hooks to the studs that have been welded into the deepest part of the dent. Slight upward pressure is applied by the technician as the damaged area is slowly heated. Bridge