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Chapter 8 Nonstructural Panel Repair
Figure 8-50. In a tight fold, the folds touch. Stretching
is necessary when repairing these types of folds.
4. Filing—File across the repair area to identify high
areas and low areas. Avoid body lines. Pick and file
to restore panel contour.
Finishing
As previously mentioned, roughing out restores the
approximate contour of a panel and finishing completes
the repair by restoring the exact contour. The roughing out
process must be completed before attempting finishing.
Any remaining buckles and stretched or upset areas will
cause problems during the finishing process. There are
two ways to finish a panel: metal finishing and filling.
Metal finishing means the lows and highs will be removed
entirely by picking and filing after the roughing process is
complete. In filling, body filler is applied to low areas and
block sanded to restore the exact shape of the panel.
Metal Finishing
Metal finishing is the continuation of the pick and
file process started during roughing. If metal finishing is
done correctly, no filler will be used in the repair.
To metal finish a panel, both sides of the panel
must be accessible. Metal finishing is most successful
on arrowheads in high-crown or double-crown panels
without a body line. The arrowheads can be roughed
out and the contour restored by metal finishing because
the high-crown or double-crown panels are stiff enough
to be easily worked. Additionally, high-crown panels are
less likely to stretch than low-crown panels. Filler is a
better choice for low crown and panels with body lines.
During the metal finishing process, every high area
must be tapped down and every low area must be
tapped up. Continue picking and filing until the panel is
smooth and level. Identify high or low areas with a metal
file or a grinder. The metal file or grinder disk contacts
and marks high areas; low areas are not contacted by
the file or grinder disk. Use short file strokes on double-
crown panels. You can also check for highs and lows
with a straightedge or with your hand. If you find a low
area that is 1/8" in diameter or smaller, tap the area up
with careful blind picking. One well-placed tap should
be all that is required. Try not to raise the low area too
much. File or grind to eliminate high areas that are 1/8"
in diameter or smaller. Low or high areas that are larger
than 1/8" in diameter should be moved with a series
of light taps around the perimeter that gradually work
toward the center.
When lowering a high area, do not cause the adja-
cent metal to collapse by tapping too hard. Support
adjacent areas with a dolly. As the metal is worked, the
picking will tighten the metal, making it less likely to
move. Try to lower the panel to the proper contour rather
than tapping a high area down and making a low spot.
You must then tap the low area up. Too much tapping up
and down will harden the panel, making it unworkable.
Filling
Filling involves the use of filler to restore panel
contour once roughing out is completed. There are two
types of filler used on vehicles: body filler and lead filler.
Body filler, or plastic filler, is far more common than lead
filler. Body filler requires less skill to apply than lead
filler. When used properly, body filler is as durable as
lead filler, except that lead filler will not crack as body
filler does if a filled panel bends or flexes. Restoration
shops and a few body shops still use lead filler.
Using Body Filler
Body filler should not be thicker than 1/8". Low spots
deeper than 1/8" should be raised before filling. False
stretch must be shrunk or eliminated. If a false stretch is
popped in and filled, the “oil can” will eventually pop out
Unibody
tie down
Unirail
damage
Hook
up
Pull
Figure 8-51. Much of the indirect damage on this quarter
panel will be pulled out when the frame rail is lengthened.
Folds touch