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EZIARC 160 • EZIARC200
20
o
1.6mm (1/16”)
Striking an Arc
(Fig 1-20)
Arc Length
The securing of an arc length necessary to produce a
neat weld soon becomes almost automatic. You will
find that a long arc produces more heat.
A very long arc produces a crackling or spluttering
noise and the weld metal comes across in large, ir-
regular blobs. The weld bead is flattened and spatter
increases. A short arc is essential if a high quality
weld is to be obtained although if it is too short there
is the danger of it being blanketed by slag and the
electrode tip being solidified in. If this should happen,
give the electrode a quick twist back over the weld to
detach it. Contact or “touch-weld” electrodes such as
E7014 Stick electrodes do not stick in this way, and
make welding much easier.
Rate of Travel
After the arc is struck, your next concern is to main-
tain it, and this requires moving the electrode tip to-
wards the molten pool at the same rate as it is melting
away. At the same time, the electrode has to move
along the plate to form a bead.
Making Welded Joints
Having attained some skill in the handling of an elec-
trode, you will be ready to go on to make up welded
joints.
A. Butt Welds
Set up two plates with their edges parallel, as shown
in Figure 1-21, allowing 1.6mm to 2.4mm gap be-
tween them and tack weld at both ends. This is to
prevent contraction stresses from the cooling weld
metal pulling the plates out of alignment.
Plates thicker than 6.0mm should have their mating
edges bevelled to form a 70º to 90º included angle.
This allows full penetration of the weld metal to the
root. Using a 3.2mm E7014 Stick electrode at 100
amps, deposit a run of weld metal on the bottom of
the joint.
Do not weave the electrode, but maintain a steady
rate of travel along the joint sufficient to produce a
well-formed bead. At first you may notice a tendency
for undercut to form, but keeping the arc length short,
the angle of the electrode at about 20º from vertical,
and the rate of travel not too fast, will help eliminate
this.
Tack Weld
Butt Weld
(Fig 1-21)
Electrode
20
o
- 30
o
Tack Weld
by scratching the electrode along the plate surface
in the same way as a match is struck. As soon as
the arc is established, maintain a 1.6mm to 3.2mm
gap between the burning electrode end and the par-
ent metal. Draw the electrode slowly along as it melts
down.
Another difficulty you may meet is the tendency, af-
ter the arc is struck, to withdraw the electrode so far
that the arc is broken again. A little practice will soon
remedy both of these faults.
The electrode is directed at the weld pool at about 20º
from the vertical. The rate of travel has to be adjusted
so that a well-formed bead is produced.
If the travel is too fast, the bead will be narrow and
strung out and may even be broken up into individual
globules. If the travel is too slow, the weld metal piles
up and the bead will be too large.
