Automotive Bodywork and Rust Repair
Page 30
metal returned to normal. The key to this result was in understanding the role
calipers to precisely transfer its
of the small area of direct damage, and relieving it.
position to the decklid’s back side.
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AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
R E PAI R I NG C OLLI S ION DAMAG E I N A DECK LI D
Next, a line was drawn to
7
indicate the exact position of
the direct damage, under the sub
The prying was done with the bent part of a pry bar, inserted through the
8
structure. It is along this line that
sub structure hole in the center of this photo. The pry bar shaft was
force was applied with a pry bar,
marked for depth of insertion, indexing it to the left edge of the hole.
against the decklid skin, to work the
direct damage out.
It was critical to watch, and to
10
evaluate, the effect of each pry
bar twist. A second worker sometimes
provided another set of hands,
stabilizing the panel, while hamm-
ering lightly on the rim of the direct
damage dent, as Herb applied prying
force to it.
Once the pry bar was positioned,
9
the bending operation was
accomplished by twisting it. After
several attempts, the chalk mark on
the pry bar smeared, but we could feel
the proper depth of insertion by then,
and did not need to see it.
Once the small knot of direct
11
damage had been pried out, we
went to a broader prying tool, to force
out the area of metal surrounding it.
That look visible on Herb’s face is
genuine teeth-grittin’ determination.
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
139
CHAPTE R 13
once the relatively small areas of
deformed metal that are holding it
out of position are removed.
It is critically important that the
attempt to pry the direct damage
area out, and to release the metal
that it has locked out-of-place, be
made with the greatest possible accu-
racy. A near miss would create a seri-
ous problem that would have to be
corrected. For that reason, we trans-
ferred the exact position of the direct
damage line from the front to the
back of the panel with a large pair of
calipers. Then, we made a chalk
Some areas of displaced metal
mark, indicating the exact area
13 resisted movement by our soft- under the decklid’s substructure,
With the locking factor of the
rubber mallet. A dead-blow plastic
from where the prying force would
12 metal in the direct damage
shot mallet proved ideal for
have to be applied.
relieved, a soft-rubber mallet was
persuading these areas back into
We selected a suitable body-
used to push out the un-deformed
place. Both the rubber and dead-blow
prying tool, and marked its depth
metal that comprised most of the
mallets were used more to remind the
behind and into the substructure
area of the dent. Access to this area
un-deformed metal where it belonged
hole. We then inserted it through the
was refreshingly good.
than to form it.
hole to accomplish the prying
It is always useful to mark
15 areas of a panel that require
straightening work. As Herb tapped
lightly on the panel’s topside, he felt
As the straightening work progressed, Herb kept feeling the surface of
and marked where he was tapping on
14 the panel to confirm its progress toward its final format. The importance its reverse side, identifying an area
of checking work by feeling it cannot be overemphasized.
that still needed to be lifted.
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AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
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maneuver. The whole process was
performed as carefully as possible,
since one false move could worsen
the damage. The initial move in this
job was to work out a small but
strongly deformed knot of metal, as a
first step in releasing the damage.
This meant applying considerable
but very accurate force to a very
small spot. The twisting motion of a
pry bar was ideal for this purpose
because it confined the applied force
to a small area.
The prying was done very slowly,
and in many small, incremental
steps. It was critical to watch the
metal that was being pried move,
from the outside of the panel, to
determine when it had been moved
far enough to accomplish the first
stage of restoring the panel to its
Pry bars are useful for raising broad areas of low metal when you
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original format.
cannot access them directly. Here, Herb lifted a shallow dent. He lightly
The actual amount of movement
hammered the ridges surrounding it, on the other side, while lifting its central
in the direct damage area was so
crease with pressure from a pry bar.
small that a photo of it would be
hard to distinguish from a photo of
Additional areas of panel damage
are critical to doing autobody damage
the area before prying force was
were located visually, and by feeling
repair work efficiently and well. In this
applied to it. Nonetheless, that small
the panel, and were marked and ham-
work, the simplest and most direct
movement of metal in the panel
mered out with appropriate tools.
approach is often the best approach.
released the locking force at the
This work requires imagination
In a relatively short time, we
point of the direct impact. Next, we
in how best to use tools in ways that
accomplished a dramatic improve-
applied broader force with a large,
will accomplish your goals. You look
ment in the panel. After the initial
curved prying spoon. This worked
at a problem and try to find a tool, or
roughing out of the dents, we felt the
out the larger area of metal around
tool combination, that will solve it.
damaged areas, and located and
the direct impact area.
We used several different prying
relieved a few points that were still
The back of the panel was then
tools to remove this damage.
locking in displaced metal. Then, we
lightly worked with a rubber mallet,
Sometimes, the best tool to do
applied mild force to move the
and with dead-blow mallets. During
part of a job isn’t in your collection.
undamaged metal out, and into
its
this work, a dolly was held against
When that happens, you have to
proper positions. Those few opera-
the ridges on the outside of the
improvise—imagine what is needed
tions greatly improved the panel.
panel at the edges of the dent. In
and then create it.
However, we were still far from fin-
some cases, the buckles at the end of
Sometimes a simple maneuver,
ished with this job.
the
damage—where
the
panel
like inserting a small block of wood
By its nature, autobody panel
finally stopped the deforming metal
under a spoon and hammering it
work is incremental. It takes many
from advancing during the impact—
through a hole in substructure, will
well-planned steps to accomplish
were hammered down lightly, as the
accomplish what is needed. Small,
goals. Each action should improve
panel was reshaped with light pries
specific solutions that accomplish
the result. Each action, when possi-
and soft blows on its back side.
tasks that address the right problems
ble, should be small enough to be
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
141
CHAPTE R 13
Inserting this little scrap of
A spoon was inserted over the wood block to apply force to it. However,
17
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wood between the back side of
using the substructure above the spoon would not work for a prying
the decklid panel and its substructure
fulcrum. The structure was not strong enough.
allowed two other tools to accomplish
a job that they could not have done
reversible because some moves may
There is some overwork in the area of
without the wood block. Because the
not achieve their desired results and
the original impact damage, where it
wood was soft, it did not leave its
may need to be undone. Many small
was pried out, but this can be cor-
outline in the metal.
actions are often far better than a few
rected later.
big ones.
Next, our priority was to remove
The area of damage in the right
the remaining big ridge in the right
side dent has been greatly reduced.
dent area. This was done by
The solution was to use a rod,
19 and to hammer down on the
back of the spoon. A few strong
blows were enough to do the job.
At this point, the panel showed marked improvement. There was some
20
Three simple tools, used together,
overwork on the direct damage crease, just above Herb’s fingers. And
accomplished what, in this case none
one buckle above that still had to be worked out. The mild dent, below and to
of them could do individually.
the left of the buckle, was pried out easily.
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AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
R E PAI R I NG C OLLI S ION DAMAG E I N A DECK LI D
Working through the substructure, behind the panel,
21 required innovative uses of tools. The action
replaced simple blows with a body hammer with very
heavy blows struck against a body spoon’s shank. This is
not a good situation, but it sometimes comes with the
territory of panel work.
hammering down its locking edges,
while applying pressure to the back-
side of the V-channel through what
access points were available. It would
be far better to hammer directly on
the V-channel, off-dolly, but limited
access prevented this approach.
Similar prying work was applied
to the rest of the major dents in the
panel, until most of the metal in it
was in roughly the correct positions.
Mapping damage helps to keep
tabs on the amount of work that
Pressure, applied against the
remains to be done, and may suggest
23 main V-channel in the lower-
sequences for attacking it.
right dent with a big, curved body
The major crease in the right
spoon, combined with light blows
dent area was mapped on the reverse
against its surrounding ridges on the
side of the panel, so that it could be
panel’s surface, allowed much of the
driven out by hammering against it
In this view of the panel, you
metal locked in this dent to move
on a curved body spoon. It was
22 see the ridges and buckles that back into place. Body metal has a
important to back up the area of the
were still locking what was left of the
long memory. If you can identify and
crease to limit the deformation by
dent. With good access to the back of
correct the deformations holding
the spoon that was being hammered
the panel, it would have been easy to
damaged metal out of place, you can
against it. This was done by placing
hammer the V-channels out, off-dolly,
rely on that memory to return much,
and backing up the panel on a
while supporting the buckle ridges
or most, of the metal in a damaged
resilient surface made up of several
with a dolly.
area to its correct positions.
layers of corrugated cardboard.
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
143
CHAPTE R 13
At this point, the major metal
moving had been completed, and it
remained to work out several small
areas of damage, the ones indicated
in chalk on the panel surface. A
small dent in the edge of the decklid
jamb area was corrected with a few
hammer-off-dolly blows. The rest of
the job was mostly small corrections
like this one.
Some of the small-damage areas
that required repair had inevitably
occurred in the process of prying out
the major dents in this panel. If the
panel had not presented such severe
access problems to its back side, it
would have been possible to remove
The damage map, chalked on the remaining damaged areas of the
the major damage with traditional
24 decklid, indicates where metal still needed to be raised (minus
hammer-on-dolly and hammer-off-
signs)and two areas where it had to be lowered (plus signs). Areas that are
dolly techniques. That would have
particularly obvious, like the area of the direct damage, were not mapped.
greatly reduced the amount of small,
A curved, double-ended spoon
26 was chosen to work this
crease, because it had the right
curvature for the job. To avoid
The center of the major remaining crease was transferred to the back
damage to one of the spoon’s
25 side
of the panel’s substructure. This made it easier to locate the crease working surfaces, a bronze hammer
by feeling for it with the body spoon that was used to work it out.
was used to beat on it.
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AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
R E PAI R I NG C OLLI S ION DAMAG E I N A DECK LI D
This small dent, in one of the
27 decklid’s edges, is typical of
damage that can be dealt with
The dolly was held so that hammer blows moved the metal edge out, as
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effectively with the traditional
pressure and rebound from the dolly pushed it in. Metal was never
hammer-off dolly approach. It offers
squashed between the tools, and no stretching occurred. You could reverse
perfect access from behind to hit it
this approach, hammering the bulge down, while supporting the back side
out with a few blows.
with the dolly.
collateral damage repair necessitated
by approaches like prying and spoon
hammering that were used to work
around the panel’s substructure.
This can be tedious and repetitive
work, but each blow should bring the
panel closer to its correct shape. It is
important to avoid stretching the
metal. This means hammering it off-
dolly, to raise low areas. If a hammer
blow is accidentally struck on-dolly,
its sound and feel will announce the
mistake. One such accidental blow
does little harm.
It is critical to use tools that are
shaped correctly for the job at hand.
The crowns of hammers must
roughly match the crowns of the
panel areas that are being worked
out, and dollies have to contact the
After more work, the panel was remapped, and looked like this. Visible
metal that you are trying to stabilize.
29 sanding-board marks helped indicate low and high spots. Note the tic-
Soft tools like rawhide mallets,
tac-toe item, top left. I need to state that this kind of fooling around has no
shot mallets, and hand held shot
place in serious work. By the way, I won.
bags can be very useful in limiting
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
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CHAPTE R 13
As the work progressed, the
With proper technique,
Backing devices like this leather
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crowns of the tools used to
hammering off-dolly can be
bag, filled with lead shot, were
perform it became more critical. This