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Chapter 8 Nonstructural Panel Repair
dinging hammer. Use a gradual approach. Start at the
bottom of the arrowhead and work upward. Alternate
tapping from one side of the arrowhead to the other.
3. Raising—As the arrowheads are pulled out, weld ad-
ditional pins in any remaining low areas. Raise these
areas gradually, starting with the lowest pin and end-
ing with the highest. Pull each pin slightly in an effort
to gradually restore the crown in the panel. Remove
the pins and check the damaged area for level.
4. Leveling—Any remaining high areas should be low-
ered by tapping. Tapping on high areas without sup-
porting adjacent low or properly contoured areas may
cause the crown to collapse. Weld draw pins in place
to support adjacent low or properly contoured areas.
While holding a draw pin to support the panel, tap any
high areas with a dinging hammer.
5. Shrinking—Any metal that was pulled too high by a
draw pin can be lowered by shrinking with the draw pin
welder. Heat the area with the welding tip, tap the heat-
ed area twice, and then cool the area with a wet rag.
One-Sided Repair, Body Line
The steps in performing a one-sided arrowhead
repair that involves a body line are as follows:
1. Raising—Weld a line of draw pins to the damaged
body line. If a gang clamp is available, hook it up to
the draw pins. Partially raise the body line. If a gang
clamp is not available, use the slide hammer to raise
the body line, starting with the lowest pin and ending
with the highest. After partially raising the body line,
weld a draw pin below the point of the arrowhead.
Use a slide hammer to pull the pin out.
N O T E
A W-shaped wire can be used in place of draw pins to
raise the body line. If W-shaped wire is used, pull it with
a claw handle. See Figure 8-48.
2. Leveling—While pulling out on the pin below the point
of the arrowhead, use a dinging hammer to lower the
sides of the arrowhead. Work from the outermost
parts of the arrowhead’s sides toward the point.
3. Raising—Return to the draw pins in the body line.
Raise them to the proper height. Set draw pins in
the shaft of the arrowhead. Raise these low areas by
starting at the ends and working toward the center.
4. Shrinking—Any metal that was pulled too high by a
draw pin can be lowered by shrinking with the draw pin
welder. Heat the area with the welding tip, tap the heat-
ed area twice, and then cool the area with a wet rag.
Two-Sided Repair, No Body Line
A two-sided arrowhead repair that does not involve a
body line is relatively simple. The high-crown panel is stiff
enough to be metal finished, but it may also be roughed out
and filled. If a change in panel length is present, begin with
step 1 below. If the panel length is correct, begin with step 2.
The steps in performing this type of repair are as follows:
1. Pushing—Use a four-ton hydraulic power set to re-
store the length of the panel. As the panel length-
ens, the lift reaction will raise the low area.
2. Raising—Use a dolly with the same contour as the
underside of the undamaged panel to hit just under
the point of each arrowhead. Start with the deepest
arrowhead and gradually raise each. Continue tap-
ping with the dolly until each arrowhead is raised.
3. Leveling—Hold the dolly tightly against the area un-
der the point. Use a dinging hammer to lower the
high ridges on the side of each arrowhead. Start at
the bottom of the arrowhead and work toward the
point. Alternate sides when hammering toward the
point. The leveling releases the arrowhead.
4. Stretching—If the arrowhead has a sharp point that
was not removed by hammer-off-dolly tapping, use
hammer-on-dolly technique to stretch the upset met-
al. Press a dolly with the same contour as the under-
side of the undamaged panel against the inside of
the panel, under the point of the arrowhead. Tap on
the point with a stretching hammer. Start with light
taps. If the metal does not stretch, tap harder. Use
the dolly to raise the low areas that remain once the
arrowheads have been released. Tap out on the un-
derside of the panel with the dolly. If an upset area—
a V-shaped groove in the shaft—remains, it can be
removed by hammer-on-dolly stretching. Start ham-
mering on the dolly at one end of the V-groove and
work toward the other end. See Figure 8-49.
Claw handle
W-shaped wire
Figure 8-48. When performing a one-sided arrowhead
repair that involves a body line, raise the body line first.
Here, W-shaped wire has been welded to the body line and
a claw hook is attached to the wire to pull the damage out.