clearly visible. The low spots were
tendency to lose its shape in the
it, as well as any filing particles that
shallow, and numerous enough to justify
repaired area. Since the hinge-mount
remained on it.
applying lead over the whole area.
area can be highly stressed when the
trunk is opened, it is interesting to
speculate whether the greater adhe-
sion and strength of the lead part of
the repair gives it better durability
than the plastic part of the repair.
The repaired area was filed to
indicate any low or high spots. Some
low areas were found and partially
corrected by picking them up, off-
dolly, while using a shot bag for back-
ing. At this point a few very shallow
8
As the tinning flux was squirted
depressions in the metal remained,
onto and brushed around the
After the panel repair area had
9
most prominently behind the hinge-
repair area, it sizzled and steamed. This
cooled a bit, excess flux was
mount relief area and to its immedi-
was a good indication that it was doing
wiped off. It is important not to wipe
ate left. It might have been possible
its job. The purpose of flux is to clean
all the flux off, or it cannot do its
to raise these areas to level with more
base metal and to promote solder flow.
important job.
pick-hammer work, but their depth
was so shallow that filling them
dry. This should be repeated until
der that is used to bond lead filler
seemed like a better approach.
the solvent-wiping rags and drying
material to it. To remove these
rags come up clean.
adhesion-robbing
contaminants,
Applying Lead Filler Material
It is usually a good idea to lightly
and to perform other wetting and
sand or blast the metal to be tinned
adhesion-promoting goals, apply a
The first step in applying lead
with a fine-grit abrasive paper or
flux to areas to be leaded. There are
filler is to clean the area to which it
blast media, to remove oxides and
many types of liquid, powdered, and
will be applied with a good, degreas-
protective coatings. This should be
paste fluxes on the market. Some of
ing solvent. The adhesion of the tin-
done before it is solvent washed, so
them include solder particles in their
ning solder that bonds the lead filler
that the solvent washing removes
formulations, and make fluxing and
to the panel is compromised by any
sanding debris.
tinning a single-step process.
traces of rust, paint, oil, or grease.
Although metal may look clean
I prefer to use a straight liquid
Always degrease any area that you
after sanding and solvent washing, it
flux that is designated specifically for
plan to fill with lead. This is done by
still has oxides and contaminants on
autobody lead work. This is available
wiping it down with rags, doused in
its surface that interfere with the
from many autobody and catalog
solvent, and then wiping the area
proper adhesion of the tinning sol-
sources. It is applied to metal that has
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
87
CHAPTE R 9
Next, 50/50 solder was applied
It takes some practice to stub
10
12
from a coil to the fluxed,
The solder was applied from
lead from a bar onto tinned
11
heated metal. Note that the torch was
the coil, and complete tinning
metal. The trick is to keep the tinned
not applied to the solder directly, but
was achieved by using a rag to rub it
metal hot with the torch’s outer flame,
to the panel metal. You can see a
around on the panel’s heated area.
while softening the end of a solder
completely tinned area behind where
You may accidentally singe a few rags
bar enough with its inner flame to
the solder is being applied.
as you are learning to do this.
twist it onto the panel.
inexpensive air-draw tip attachments
solder onto it, but not to overheat it
for oxy-acetylene torches that con-
by getting it much hotter than that.
vert them to air-acetylene operation.
Never apply your flame directly
These are a bit clumsy, but they do
to the solder from the coil. As you
work. Note that an oxy-acetylene
melt solder from the coil onto the
flame is much too hot for perform-
base metal, keep playing the torch
ing lead work. Propane torches are
over several square inches of the area
sometimes used for this work, but
that you are tinning. Then, when
their flame is not as long and gradu-
you have deposited enough solder to
ated as is the air-acetylene flame.
do the job, spread it out with a rag
As the lead-shaping work
After the target area has been
until it thinly and consistently cov-
13 began, the paddle was
fluxed, it is a good idea to scrub off
ers the heated area. The solder
lubricated, to keep it from sticking to
any excess flux residue with a rag
should have a shiny appearance as it
the lead as it was spread. To do this,
and/or
spun-nylon
pad.
These
bonds to the metal. Be careful to
we liquefied the surface of the tallow
residues may appear as heavy,
wipe it lightly when you spread it, or
with the end of the torch flame and
brown, gummy deposits, or they
you will remove the solder com-
dipped the working surface of the
may not be present at all. Be careful
pletely, rendering your tinning pro-
paddle into it.
not to scrub down to bare metal
cedure useless.
because a flux coating is necessary
After the entire area to which
been heated to the point that it sizzles
for adhesion of the tinning solder
you plan to apply lead is tinned, it is
off the liquid flux, when it is sprayed
that you apply over it.
time to apply the body lead. My pref-
or dripped onto it. Flux application
Tinning is accomplished by
erence is to use 1/2-pound bars of
turns the metal a light gray color.
keeping the fill area hot with your
30/70 body lead. Appendix I shows
The best flame to use for fluxing,
torch, while melting enough 50/50
&nb
sp; the transition temperatures for vari-
tinning, and applying body lead is
tin/lead solder from a coil onto the
ous tin/lead solder alloys, from solid
one from an air-acetylene torch,
metal to cover the area when that
to paste to liquid. My experience
often called a “plumber’s” torch.
solder is spread uniformly over it. It
tells me that 30/70 is the best alloy
This type of torch produces a flame
is important to use the middle-to-
for most body lead applications,
that is long, and graduated in tem-
end part of your torch flame to keep
with some minor exceptions, like
perature along its length. There are
the metal hot enough to melt the
sealing seams, which may be better
88
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
F I LLI NG
We worked the lead with the
14 end of the torch flame to heat it
The paddled lead in this
16
uniformly to its paste state. We did
We repeatedly tested the lead
example looked like this when
15
this slowly enough to heat through
surface with the paddle, to
its application was completed. The
the entire filler thickness, not just its
indicate when it reached a plastic
dark residues on its surface are
surface. Note that while the lead was
state. A short time after it first
tallow lubricant and flux residues
being heated, the paddle was held at
become plastic, it was ready to work
from tinning that worked up through
the ready.
with the paddle.
the lead.
no good because the tin and lead will
deposited enough lead where you
no longer be alloyed. Without the
need it to accomplish the filling.
tin/lead alloy, there is no plastic state
At first, it is likely that you will
in which this material can be formed
deposit more lead than you need.
with leading tools. Of course, if you
Later, with experience, you will learn
allow your lead to cool too much, it
to deposit the right amount of lead
becomes solid, and resists any
filler for your filling purposes.
attempts to shape it with paddles.
The chief obstacle for novices is
The tallow and flux residues
Before you try to form lead, you
overheating their work areas, and liq-
17 were removed before filing
have to deposit it on the area where
uefying the lead. This is a common
began. To do this, a metal conditioner
you are going to use it. You do this
problem with a simple, but not obvi-
was wiped onto, and scrubbed off,
by heating—but not overheating—
ous, solution. Overheating is made
the leaded surface. This removed
the tinned area of the base metal by
worse because people tend to move
these contaminants.
playing the last few inches of your
their torches sideways when they
torch flame over it. As you are doing
sense that it is occurring. That simply
served by using a 20/80 alloy. A
this, hold a lead bar against the
results in overheating another area,
30/70 lead bar has a plastic state of
panel in an area where you want to
one adjacent to the area that was the
about 130 degrees F. As long as you
deposit lead filler, also keeping the
original problem. The answer is to
keep it in that temperature range, it
end of the bar warm with the torch.
move your torch in-and-out from
will have a consistency something
Slowly attack the base of the lead bar
your work, not to the side, to control
like peanut butter. In this state, it is
with flame that is nearer to the hot
heat. This approach helps you to
easy to work with leading tools.
inner cone of your torch flame, until
maintain your 30/70 body solder in
If you overheat lead, it goes to
it begins to soften. You will see and
the 130-degrees-F range in which it is
liquid and, likely as not, ends up on
feel this happening. When the lead
plastic. It takes some time to perfect
your shoes and/or on the floor. At the
on the end of the bar (about 1 inch
this somewhat unnatural torch
very least, when body lead is over-
or less) is soft enough to deform eas-
manipulation but, after a while, it
heated to its liquid state, its tin and
ily, twist it off and onto the panel.
should become quite natural.
lead components tend to separate.
Then, move to another spot and
The best lead-working tools are
Trying to re-soften separated body
deposit another stub. Continue this
paddles made from seasoned hard
solder, after it has re-solidified, does
stubbing process until you have
maple, boiled in mutton tallow.
AUTOMOTIVE BODY WOR K AN D R UST R E PAI R
89
CHAPTE R 9
As filing continued, areas of
19 base metal appeared through
the body solder. Correct filing
Panel edges should be filed
20
A body file in a flexible holder is
technique ensured that the
18 my favorite general filing tool,
continuous contours being filed into
pressure, accurate file position, and
my first choice of weapon for small
the repair area were the correct ones.
constant monitoring of shape are
and large body-solder filing jobs. It is
It is always a good idea to file across
essential when you file panel edges.
versatile and accurate. That setup was
as much leaded area in one operation
Any inattention can result in damage
used here to file the leaded surface.
as possible.
to a panel.
Mutton tallow is also the preferred
lead a 11⁄2-inch-round shape, it will be
vinegar, and other household sub-
working lubricant for these tools.
possible, but difficult to accomplish
stances, to the metal conditioners
Other popular lubricants, like beeswax
this work with a flat or convex lead-
used to prep metal for painting. A
and chassis grease, cause all kinds of
paddle working surface. The solution
good metal conditioner is your best
problems and should never be used.
is to make your own tool for this pur-
bet for neutralizing contaminants in
To apply fresh lubricant to a maple
pose. It’s just too inefficient to try to
worked lead. Phosphatizing condi-
paddle, you play the end of your air
-
do the job with an incorrectly
tioners are among the most effective
acetylene-torch flame over the surface
shaped tool.
chemicals in this class, and are read-
of a tin of mutton tallow, until it melts
In the example above, I would
ily available from body shop supply
to a depth of about 1/2 inch. Then,
take a stick of kiln-dried hard maple,
outfits. A good move at this point is
dip the work contact surface of the
say 2 x 3/4 inches, and form a
to use a nylon scrubbing pad with
paddle into it. Let the excess tallow
radiused, chamfered, and tapered
your metal conditioner, or other
drip off the paddle, back into the tin.
end on it, starting at about a 13⁄4-inch-
killing agent, to scrub off any visible
The paddle is now lubricated.
round diameter. Then, I would boil
tallow residues on your paddled lead
To work, or form, the lead that
the new tool’s working end, for an
filler surface. Flux residues from tin-
you have stubbed onto the work area,
hour or so, in a tin can with about 2
ning that may have worked up
you use your properly lubricated pad-
inches of mutton tallow in it.
through the body solder may not be
dle to spread it onto the areas where
This step is often left out of the
visible but if they are there, and if
you need it. Deposit the lead a bit
leading process and which, when
you file them into your lead, they
thicker than the approximate thick-
omitted, results in endless later grief.
will cause trouble later.
ness to which you will finish it. Keep
It is critical to kill lead at this point;
You will need to perform the
the lead soft by playing the end of
that is, right after it is applied to
killing process again, when your lead
your flame over it. While you keep it
metal and paddled into preliminary
filler has been filed into final shape.
in its plastic state, it is easy to form it
shape. Killing, in this case, means
That is a precaution to make sure
with your paddle. Of course, all of
removing
flux
and
lubricant
that these residues are completely
this takes some practice, but, with
residues from your work. If left in
removed from your work. The best
the benefit of some experience, it is
and on the lead, such residues would
time to remove them is now, when
not difficult to master.
later raise havoc with primer and