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By Jim Wilk, Licensed Auto Body Technician
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This Ford F250 got too close to a boat trailer
at the marina. There were two gouges in the
side of this vehicle, indicated by the pairs of
red arrows. |
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There is a gouge above and below the
structure line. (Structure lines are used in open areas of
sheet metal to give strength.) |
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| I'm repairing
the top crease first. |
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I exposed the metal in the crease and at least 4 to 6
inches around it. This dent was an exception
because the structure line just below it, so I
only removed the paint just beyond the edge of
the "valley" of the structure line. |
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| Then I
applied the studs with the stud welder. |
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With the
slide puller I pulled the metal out and hammered the
high spots and ridges. The goal here is to
pull the metal outward and then hammer it back
just enough to make the surface smooth. This
pull-and-hammer technique is used for each stud
as I progress along the crease. |
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With nippers
I squeezed the head of the stud and twisted to
cut it off. |
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| Next I moved
to the gouge below the structure line.
By pulling out the top dent first, there
was no longer any "tension" holding the door
inward. |
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WHY? The crease at the top
helps prevent the sheet metal from "oil-canning".
BUT... in this case we want the sheet metal to
"oil-can" and pop outward. So I removed the top crease first
and then used the suction-cup puller to force the metal to
pop out.
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With a
pneumatic suction cup I pulled most of damage
outward. |
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| This
pneumatic suction cup can pull with a force of
up to 90 pounds. |
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I purchased
this tool over 35 years ago and the company went
out business 30 years ago. Many technicians and tool
men have tried to find this tool and can't. |
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| After baring
the metal I placed the studs, following the
crease all the way down. I spaced the studs
about three-quarters of an inch apart. |
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Then after a
coffee break, I started the tedious process of pulling
every one of those studs and working the metal
with a hammer. This procedure took at least an hour to an
hour and a half. |
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Pro Technique:
Once the steel door skin has been
dented, the metal becomes stretched. Through many years of
body work experience I have learned how to heat and shrink
stretched metal. This technique was taught when I first
started my apprenticeship in 1969, but today this technique
is rarely taught.
- With a grinder, I skimmed the area, applying
light
pressure. This heated up the metal.
- Next, I lightly hammered the high spots and
ridges.
- Then I wiped the area with a cold wet
rag (red arrow).
The heat of the grinder will expand the metal
and the cold water will shrink the metal. |
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After doing
this procedure about five times I finally
had
the crease out of the metal. Other situations
may require more or less than five
heating/cooling cycles.
This heating and
shrinking process will also add strength to
metal. |
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| It is a
judgment call to know when the metal is
ready for this next step: To smooth out the
irregularities in the metal, I applied a
light layer of plastic filler. |
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Before it
totally hardened I used a grater to
level the surface. With this procedure I have
less sanding and dust. |
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| I call this a
grater, but it's also called a Surform tool. I have found
the blades at Home Depot. |
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The main part
of this tool is over 30 years old. This style of
handle may be hard to find, but similar tools
are available. |
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| When the
plastic was completely hardened I started sanding. First I used
the pneumatic sander with coarse 40 grit sandpaper. |
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After sanding with 40 grit, I
applied a coat of automotive putty filler. I used a
plastic spreader to apply a smooth coat.
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Then I
hand sanded it with a long board sander, first
with 80
grit and then I with 180 grit. |
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| Now the
repaired area was ready for priming and
painting, which was done by another
professional. |
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After the
painting was done, the painter polished and
waxed the repair area. |
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| After
washing, the truck was good as new. |
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More Info:
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Tools Used:
- Stud Welder
- Slide Hammer
- Suction Cup Dent
Puller
- 7" Disc Grinder (24
or 36 Grit Disc)
- Pneumatic Sanders
- Grater (Surform Tool)
- Long Board Hand
Sander
- Body Shop Hammers
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Materials Used:
- Studs
- Plastic Body Filler
- Sandpaper: 40, 80,
180 Grit
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