W E LDI NG BODY M ETAL
formats, by an envelope of vaporized stick
coating in stick welds, and by the inert
outer envelope of the flame in oxy-acetylene
torch welds.
Welding tape is available at high-end
welding supply stores. You tape it over the
back of a seam to be welded, and then
weld the seam in the normal way with MIG
or TIG processes. The fiberglass bandage
in the stainless-steel welding tape
releases inert gas when it is exposed to
Both sides of welding tape are
welding heat, while the stainless-steel
shown here. The side with the
tape keeps air away from the cooling
fiberglass bandage is applied to
weld. When you remove the tape, the
the back sides of weld seams
back of your weld should be positively cor-
before welds are made. This
rosion free, even shiny.
protects these undersides, and
makes for very clean and
Tip #5
corrosion-free welds.
Holding metal pieces in position for
spot welding can be a great, acrobatic
This homemade, foot-operated
Tip #3
bother. Unlike seam welding, spot welds
spot-welding setup frees both
One great enemy of copasetic body
tend to be made in many different locations,
hands for holding and positioning
metal welds is heat buildup that distorts
and setting up locking pliers, magnets, and
the pieces to be welded. This
the metal near the welds. To minimize this
other fixturing devices can be difficult and
device was designed to allow for
heat buildup, and to harden the welds, it is
cumbersome. If you try to hand-hold pieces
good foot travel at a reasonable
good practice to blow compressed air at
in place for spot welding, you wil quickly
level of applied foot pressure.
them immediately after they are made.
wish that the human anatomy included a
This holds true for MIG, TIG, and oxy-
third arm and hand assembly.
Tip #6
acetylene welding, and for any joint or
One solution is to buy or make a foot-
I saved the best and most important
bead format that you use, including tack
pedal-operated spot-welding setup, so
welding tip for last: Always weld clean
welds, short-triggered-section welds, and
that you have two hands free to position
metal. If you try to weld over rust, paint,
long-bead welds. All of them benefit from
metal, while one foot closes the spot
plating, or anything else but base metals,
some forced-air cooling to limit local heat
welder’s arms and turns it on.
you get inclusions of these things in your
buildup and to harden the welds.
One particularly frustrating spot
welds. That compromises their quality.
welding afternoon several years ago, I
Abrasive blasting, sanding, grinding, filing,
Tip #4
made the foot-operated device for my
wire brushing, etc., clean metal ade-
If you want to go fanatical about mak-
spot welder. I fabricated it from things that
quately for welding if it is done completely.
ing quality welds, you should consider
were lying around my shop. It has served
Chemical stripping also accomplishes this
using welding tape to protect the backs of
me well, ever since. Note that it is very
purpose. Whatever method you use, make
your welds from oxidation. Remember, the
easy to remove the spot welder from the
sure that any metal that you weld is as
fronts of your welds are protected by a
device, if its service is needed for mobile
clean as you can get it before you try to
supplied shielding gas in MIG and TIG
applications.
weld it.
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
83
C H A P T E R 9
FILLING
I don’t expect to work in a body
shop any time soon, but if that should
come to pass, I would like to do colli-
sion metal work, bumping, and metal
finishing damaged panels. If am ever
employed that way, it will be one of
my main objectives to give the paint-
prep guys as little to do as possible. I
have nothing personal against them,
or their employment. It is just that
good metal work should require little
or no filling before it is coated with
primer and paint. This is the last stage
of metal work and, as far as the eye
can see, probably the most important.
However, like many other issues
Looking from the panel’s back toward its front, you can see the completed
in metal work, the decisions of when,
repair of a decklid’s left-hinge mounting relief area. For demonstration
where, and how much filler to use are
purposes, the left side of the repair area was filled with body solder material
matters of degree. At some level, it is
and the right side was filled with plastic filler.
almost always possible to do enough
metal finishing, without using fillers,
adjustments, a point at which they
when to quit and to use some filler
to serve up panel work that needs
may create other problems, sometimes
to complete a job. Knowing when to
nothing but primer and some light
elsewhere in a panel. That can mean
quit is among the hardest disciplines
contour sanding to pass the muster of
backing up and doing creative destruc-
to acquire in any line of work.
the highest standards. The question
tion to your work, to try to eliminate
Body filler has a place. That place
becomes, “What does it take to get
that last niggling defect. That process
is as a corrective for minor surface
the metal to that point?” At the very
may create other problems that have
defects, and for very small shortcom-
least, it means hours spent adjusting
to be solved, often with great difficulty
ings in shape. If it is used within
surfaces to perfection.
but without success.
those limits, it is a full-fledged and
There comes a point of diminish-
Put simply, the issue becomes
respected member of the metal fin-
ing returns when you are making such
one of practicality, and of knowing
ishing family. If it is gobbed on to
84
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
F I LLI NG
cover sizeable flaws in metal work, or
added as solids to their resins. They
TR-3, year not known. There was
used creatively to produce what
also lack the adhesion to base metal
minor damage to the left-side hinge-
amounts to sculpture, it is misuse.
of properly tinned lead filler. Despite
mount area of this decklid panel.
their improvement in these two areas,
Note: The convention of describ-
The Secrets of Lead Work
I think that they remain behind lead
ing damage from the perspective of
in both regards. However, that is only
looking from the back of a vehicle
An extensive example of lead
a personal opinion.
forward should always be followed.
work is included in Chapter 12, and
The earliest plastic fillers were
Thus, in nautical terms, the damage
in the photos and captions in the
resins filled with talc. Over the years,
described here was to the port-side
first part of this chapter.
many other, less-moisture-absorbing
decklid hinge-mount area.
Lead was the unquestioned filler
substances, like marble spheres, have
The damage extended from the
of choice in body work from early
been
combined
with
greatly
hinge mount’s center relief to the
automotive times into the early
improved polyester resins to make
outer edge of the decklid. Put simply,
1950s. This was true because it was
plastic fillers. The result is plastic
the outer edge of the hood was
the only known, practical body filler.
fillers that greatly outperform the
sprung out in the hinge-mount area,
Then polyester fillers were intro-
original issues of this type of product.
and the hinge-mount area itself was
duced and, over the years, have
The bottom line for me is that
canted down and to the left.
almost completely eclipsed lead
tin/lead based fillers are metal. Applied
fillers in this work. Polyester fillers
to sheet steel, you have fillers that are
enjoy many advantages over lead. By
somewhat similar to the base metal to
comparison, the material is much less
which they are applied. Tin/lead fillers
expensive, and far less skill intensive
are far softer than the base metal, but
and time consuming to apply. Unlike
they file, sand, and finish more like it
lead particles and fumes, exposure to
than do plastic fillers.
airborne plastic filler particles is not
You can decide for yourself
particularly hazardous, though it is
which type of filler you favor in your
always a good idea to wear a protec-
work. I discuss both of them in the
tive filter mask when you sand plastic
example that follows.
fillers. Modern polyester fillers are
The decklid hinge mount area in
purported to be as durable as lead.
the photograph at the beginning of
Before this repair was begun, the
They are also claimed to be at least as
this chapter shows damage that has
panel repair area looked like this.
workable as lead when it comes to
been bumped back into its roughly
This photo was taken from the front
being filed and sanded to perfection.
correct shape, and then filled and
of the panel. Note that the relief area
I know that I am swimming
metal finished, using both tin/lead
was pushed down on the left, and the
upstream on this one, but I still prefer
body solder and plastic filler, in dif-
metal beyond that was sprung up and
lead filler. Basically, I take issue with
ferent areas of the repair. In the pho-
out from its edge.
both of the last two points, stated
tograph, the tin/lead application is
above, that favor plastic fillers. While
on the left side of the hinge-mount
The nature of this damage, and
polyester fillers have evolved enor-
relief, while plastic filler was used on
how it was removed, is not central
mously in the last 50+ years, I con-
the right side of the relief. You can
to this account of using body fillers,
tinue to doubt that they have the
follow both processes, applied to
but a little information about it pro-
durability of properly applied lead
similar situations, in the photos and
vides some useful background for
fillers. I also question that they can be
captions that follow.
that discussion.
finished as accurately. My reasons for
The decklid arrived with its
doubting their comparable durability
The Project
hinges removed. My guess is that it
to lead is that plastic fillers remain
was caught in an open position by
somewhat water absorbent, even with
The panel used as an example
strong wind, or some other force,
the modern components that are now
here is the decklid from a Triumph
coming from the car’s right rear. This
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
85
CHAPTE R 9
Decklid Panel Repair
After light abrasive blasting with
Twisting the hinge-relief area
1
3
silica sand, the damaged area
sideways, up and away from the
looked like this. The damage is more
A cardboard template was
decklid’s edge, while lightly tapping
2
obvious with the paint and rust
made from the undamaged
the metal beyond it with a body
removed from the panel. You can see
side of the decklid. Then it was turned
hammer, returned the metal to its
around and fitted over the damaged
correct format. Two incremental
hinge-mounting hole in the hinge-
area. It indicates the exact location
applications of this procedure bumped
mount area.
and extent of the panel deformation.
this area back into proper shape.
a very light blast of silica sand, a card-
board template of the hinge-relief
area was cut from the undamaged
right side of the decklid panel. Then,
it was turned around with respect to
the car, and applied over the dam-
aged area to determine the exact
nature and extent of the damage.
About halfway through the initial
The repair was accomplished
5
Filing the repair area began to
filing, the panel looked like this.
simply, by fitting a large monkey
4
reveal high and low spots. Body
Note the low spots along the right side
wrench over the damaged hinge-
files are usually held with both hands,
and to the front of the hinge-mount
relief area, with
a small wooden pad
and slid forward and sideways, with a
relief area.
under the relief and a large one on
toe-to-heel weight shift as they are
top of it. Then, the wrench was
moved. Shown here is a one-hand
ably contacted and engaged the
pulled sideways, away from the dam-
filing motion, used to isolate a
decklid jamb, springing the metal
age, while the metal beyond it, to the
particular high spot.
outward from the hinge-mount area.
left, was tapped lightly with a
The visible damage to this panel was
medium-crown hammer. This com-
probably resulted in breaking the
consistent with this scenario, but
bination of steady pressure and light
right hinge, while forcing the decklid
other sequences are possible.
impact almost completely restored
panel up, and to the left. This would
The deformation of the metal,
the panel to its original format in
have bent and canted the left-hinge-
immediately to the left of the hinge-
one planned operation that was
mount area because the right hinge
mount area, was sufficient to release
repeated twice. Correct contour was
was no longer attached to the panel,
the paint there. Then, exposure to
confirmed by checking the repaired
and could not restrain its movement.
moisture caused that area to rust.
area against the template that had
The left-front lip of the decklid prob-
After cleaning the damaged area with
been made from the undamaged
86
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
F I LLI NG
hinge-mount area on the decklid’s
The
7
other side. After the second opera-
metal in
tion, it fit perfectly.
the repair area
The strength of the repaired
was now
panel was checked by attempting to
heated, in
physically twist it in various ways,
preparation for
while observing the repair area. No
50/50 tinning
movement in the repair area was
solder
observed. There appeared to be no
Before the repair area could be
6
application.
weakness in the metal, and with two
tinned, it was repeatedly wiped
Low and high
correctly mounted hinges, it is
down and dried with enamel reducer.
spots, left by the filing operation, are
doubtful that it will show any This removed any grease and oil from