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Amperage Selection Guide
Rod Size/ Gauge
Welding Current
1.6mm
40-50 Amps
2.0mm
50-75 Amps
2.5mm
75-105 Amps
3.2mm
105-140 Amps
4.0mm
140-160 Amps
WELDING CURRENT
Welding current level is determined by the size of electrode - the normal operating range and current are
recommended by manufacturers. Typical operating ranges for a selection of electrode sizes are illustrated in
the table. As a rule of thumb when selecting a suitable current level, an electrode will require about 40 Amps
per millimetre (diameter). Therefore, the preferred current level for a 4mm diameter electrode would be 160
Amps, but the acceptable operating range is 140 to 180 Amps. It is important to match the machine to the job
Average Metal Thickness
Electrode Size
1.0 - 2.0mm
2.0mm
2.0 - 5.0mm
2.6mm
5.0 - 8mm
3.2mm
8.0mm +
4.0mm
ELECTRODE SIZE SELECTION
Electrode size selection will be determined by the thickness of the section being welded. A thicker section will
need a larger diameter electrode. The table below shows the maximum size of electrodes for average
thicknesses of section (based on General Purpose 6013 Electrode).
TIPS
• Keep the welding current as low as possible for the job at hand to maintain the best duty cycle from your
welding machine, prevent the flux from burning and make removal slag easier.
• To break the circuit withdraw the electrode from the work piece. Be careful with the end of the electrode,
as it will be HOT. Provided the current setting is correct, the surface of the work piece will also melt by the
intensity of the electric arc. A degree of “penetration” is thereby obtained, and a complete “fusion” of the
work piece and the deposited electrode is met.
• If the transformer overheats, the overload cut-out protector will activate and cut off. The light will illuminate
to show that the cut out has operated.
• After cooling, the protector will reconnect the supply circuit and the welder will be ready for further use.
Note: If the duty cycle of the machine is exceeded, the thermostatic protection will activate and the
machine will cut out, to cool down.
