Würth MIG 180-5S Mode D'emploi Original page 35

gap between the rod and the workpiece.
(see fig. N on page 10)
It is important that the gap is maintained during the
welding process and it should be neither too wide
or too narrow. If it is too narrow, the rod will stick to
the workpiece. If it is too wide, the arc will be extin-
guished. It takes a a lot of practice to maintain the
gap. Beginners may usually get sticking or arc extin-
guishing. When the rod sticks to the workpiece, gen-
tly rock it back and forth to separate it from the work-
piece. If you don't, the short circuit occurs, which
leads to welder overload. A good arc is accompa-
nied by a crisp, cracking sound. The sound is similar
to that made when frying eggs. To lay a weld bead,
only 2 movements are required; downwards and in
direction of the weld to be laid.
(see fig. O on page 10)
2.3 Types of weld beads
The following paragraphs discuss the most com-
monly used arc welding beads.
The stringer bead is formed when electrode is trave-
ling in a straight line while kept centered over the
weld joint.
(see fig. P (a) on page 10)
The weave bead is used when you want to deposit
metal over a wider space which wouldn't be possible
using a stringer bead (without transfer oscillation).
It is made by weaving electrode from side to side
with slight hesitation at the end of each oscillation
while moving it longitudinally. That is the best way to
improve weld penetration.
(see fig. P (b) on page 10)
2.4 Welding position
Flat position is the easiest of all welding positions
and is most commonly used. It is best if you can weld
in the flat position if at all possible since good results
are easier to achieve.
(see fig. Q (a) on page 10)
The horizontal positions are performed very
much the same way as the flat weld except that the
angle is different such way that the electrode, and
therefore the arc force, is directed more toward the
metal above the weld joint. This more direct angle
helps prevent the weld puddle from running down-
wards while still allowing slow enough travel speed
to achieve good penetration. A good starting
point for your electrode angle is about 30 degrees
DOWN from being perpendicular to the workpiece.
(see fig. Q (b) on page 10)
2.5 Judging a good weld bead
When the trick of establishing and holding an arc
has been learned, the next step is to lear how to run
a good bead. The first attempts in practice will prob-
ably fall short of acceptable results. Arc too long
will be held or the travel speed will vary from slow
to fast.
a. Weld speed is too fast.
b. Weld speed is too slow.
c. Arc is too long.
d. Ideal weld.
(see fig. R on page 10)
A solid weld bead requires the electrode to be
moved slowly and steadily along the weld seam.
Moving the electrode rapidly or erratically will pre-
vent proper fusion or create a lumpy, uneven bead.
To prevent ELECTRIC SHOCK, do not perform any
welding while standing, kneeling, or lying directly on
the grounded workpiece.
2.6 Finishing the bead
As the coating on the outside of the electrode burns
off, it forms an envelope of protective gasses around
the weld. This prevents air from reaching the molten
metal and creating an undesirable chemical reac-
tion. However, coating burning forms slag. The slag
formation appears as an accumulation of dirty metal
scale on the finished weld. Slag should be removed
by striking the weld with a chipping hammer.
3. The LIFT TIG welding method
3.1 Accessory
Switch off the welder. Remove mains plug from the
wall socket. Connect the ground cable to the posi-
tive dinse socket and screw it tight. Connecct the end
of the ground cable (earth clamp) to the workpiece.
Connect the torch cable to the negative dinse socket
and screw it in clockwise direction. Tighten the torch
gas hose adaptor which connects the shielding gas
cylinder. Insert the mains plug into the mains socket.
3.2 The torch pilot arc
Warning! Turn on the welder. Welding torch's tungsten
electrode is already charged. The tungsten electrode
should not touch anything. This series TIG welding
machine needs contact striking to produce the arc.
How to strike the arc method.
a. Open the built-in TIG torch gas valve. Place the
gas nozzle so that the tungsten electrode and the
workpiece are separated 2-3mm.
b. Create the arc by slowly establishing direct contact
between the tungsten electrode and the workpiece.
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