HD Manual Arc Welders
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Figure 11 - Butt weld
Figure 12 - Weld build up sequence
Heavy plate will require several runs to complete the joint. After completing the first run,
chip the slag out and clean the weld with a wire brush. It is important to do this to prevent
slag being trapped by the second run. Subsequent runs are then deposited using either a
weave technique or single beads laid down in the sequence shown in Figure 12. The width
of weave should not be more than three times the core wire diameter of the electrode.
When the joint is completely filled, the back is either machined, ground or gouged out to
remove slag which may be trapped in the root, and to prepare a suitable joint for depositing
the backing run. If a backing bar is used, it is not usually necessary to remove this, since it
serves a similar purpose to the backing run in securing proper fusion at the root of the
weld.
b) Fillet
Welds
These are welds of approximately triangular cross-section made by depositing metal in the
corner of two faces meeting at right angles. Refer to Figure 4.
A piece of angle iron is a suitable specimen with which to begin, or two lengths of strip
steel may be tacked together at right angles. Using a 3.2mm Ferrocraft 21 electrode at 100
amps, position angle iron with one leg horizontal and the other vertical. This is known as a
horizontal-vertical (HV) fillet. Strike the arc and immediately bring the electrode to a
position perpendicular to the line of the fillet and about 45° from the vertical. Some
electrodes require to be sloped about 20° away from the perpendicular position to prevent
slag from running ahead of the weld. Refer to Figure 13. Do not attempt to build up much
larger than 6.4mm width with a 3.2mm electrode, otherwise the weld metal tends to sag
towards the base, and undercut forms on the vertical leg. Multi-runs can be made as
shown in Figure 14. Weaving in HV fillet welds is undesirable.
Figure 13 - Electrode position for HV fillet weld Figure 14 - Multi-runs in HV fillet weld
