To ensure high weld quality, the correct arc length is required. Arc length depends on the arc voltage. Any change results in a large change in heat input and current.

As voltage increases, arc length also increases, causing the weld beads to become shallow and wide. Conversely, when the arc voltage decreases, weld beads become deep and high. If the voltage is excessively high voltage reduces the short circuit’s frequency, resulting in a poor weld quality. Excessively low voltage causes the wire to contact the work piece, causing the arc instability.

If the clearance between the contact tip and work piece is excessive, the welding wire overheats and melts too quickly due to the excessive length of the protruding wire. Welding current and penetration decrease.

If the clearance between the contact tip and work piece is too large or small, the effects of the shielding gas are deteriorated, which wastes gas and negatively affects weld quality. The standard clearance is 8-15 mm (0.3-0.6 in).

There are two directions in welding; forward and reverse. These are more commonly known as push or forehand, and pull, drag, or backhand technique.

The push or forward welding technique usually produces lower penetration and a wider, flatter bead because the arc force is directed away from the weld puddle.

The pull or reverse welding technique points the torch back toward the weld puddle and it is dragged away from the deposited metal. Pulling typically produces deeper penetration and a higher, narrower bead with more buildup.

With either technique, the torch should be held at an angle of 10 to 30 degrees.

A larger quantity of shielding gas doesn’t always ensure good shielding effects. Excessive gas flow prevents the gas from remaining around the weld, reducing its shielding effects.

The gas supply must be regulated depending on the nozzle-to-work clearance, welding current, welding speed and welding environment (wind velocity). The standard flow rate is 21 to 32 cubic feet per hour, or 10 to 15 liters per minute.