Table of Contents
Advertisement
Heat shrinking may be done without using a dolly block
at all, simply by heating, upsetting, and quenching; but it
is better to bump the upsets smooth as the work progresses.
FENDER WELDING:
(See CAUTION, Page 54)
Cuts and tears in fenders may be repaired by acetylene
welding. Align the edges to be welded by bumping, and
remove all paint, rust, and scale. With pliers or clamps
hold the cut together and tack weld every two or three
inches. Then, using the forehand method of welding, with
a 1/16" soft iron rod and a No. 1 tip, weld from the inside
of the cut toward the edge of the fender.
NOTE: Do not weld all the way to the edge. On the
inside of the fender, the surrounding metal absorbs
much of the welding heat. At the edge of the fender
this heat is concentrated and may burn the metal away.
To finish the weld, hold a heavier rod above the cut and
heat about 1/2" of the rod until it melts and drops into the
cut. Using a heavier rod provides enough additional mol-
ten metal to pre-heat the fender and fuse the metal. This
method makes unnecessary any reinforcements of the
weld.
When the position of the weld makes it impossible to
drop molten metal into the cut, hold the welding rod
against the edges of the cut with about 3/8" of the rod
extending beyond the fender. Heat the rod and the edges
of the cut at the same time. This allows molten metal from
the end of the rod to flow back onto the fender and
reinforce the edge.
Do not attempt to weld a fender that has been filed thin or
brazed. Cut out the thin or brazed material and weld in a
patch of new metal of the same thickness as the original
fender.
FORGING A WELD:
After a panel or fender has been welded, some method of
smoothing the bead of the weld is necessary before
painting
painting. It is not advisable to file the bead because this
weakens the weld. The welded seam may be smoothed by
cold shrinking (Page 55) and solder filling (Page 54). A
more economical method is forging the weld as it is made.
To forge a weld, weld about in at a time; then quickly drop
the rod and hammer the bead smooth, using a bumping
hammer and a dolly. Repeat this process along the entire
length of the break. Forging the weld leaves a strong,
smooth seam ready for sanding.
FILING:
The body file ordinarily used in body and fender work is
the Vixen file. The Vixen file is flexible and may be
adjusted to the contour of the area being filed. The file
should be held at an angle of 30° to the line of travel and
worked with long, even strokes, using the adjacent un-
damaged metal as a guide. Short, choppy strokes gouge
the metal and make the sanding operation difficult.
Filing is used before and during the bumping and dinging
operations to mark the high spots and to smooth dinged
and solder filled surfaces. Care must be used in filing
solder filled areas since the solder is relatively soft and
easily cut. Use the Vixen file lightly over the soldered area
to establish the contour; then finish filing with an open-cut
solder float file.
CAUTION: DO NOT FILE HIGH POINTS TO
BRING THEM DOWN TO THE LEVEL OF THE
LOW SPOTS---BRING THE LOW SPOTS UP TO
THE LEVEL OF THE HIGH POINTS BY SOL-
DER FILLING. EXCESSIVE FILING WEAKENS
SHEET METAL AND SHOULD BE AVOIDED.
DINGING WILL TAKE OUT SMALL DENTS OR
SOLDER WILL FILL THEM. IT IS FAR BETTER
TO HAVE A LITTLE TOO MUCH METAL AS A
RESULT OF SOLDER FILLING THAN IT IS TO
HAVE A THIN AND WEAKENED AREA
CAUSED BY TOO MUCH FILING.
BODY MANUAL
57
Advertisement
Table of Contents
