LW/RW welding techniques are founded basis on gas welding and later used with other welding techniques. There are two techniques for producing welded joints based on this classification as:
- Leftward or Forehand welding Technique
- Rightward or Backhand welding Technique
The difference between Leftward and rightward welding is the way the torch is moved and handled during the welding process as explained in this article.
Leftward or Forehand welding Technique
In Leftward Welding, the welder holds the welding rod in the left hand and the welding torch in the right hand. The welder guides the welding torch in a straight line and moves the welding rod in a dabbing action (the welding torch follows the welding rod). The welding is started from the right side towards the left side. The welding torch follows the welding filler wire & heat is directed away from the finished weld to the area to be welded thus giving clean and neat welds. The leftward technique is used for welding thin plates usually less than 6 mm or 0.25 inches.
Advantages: Smooth or only slightly scaled weld surface; favorable use up to 3 mm workpiece thickness.
Disadvantages: Easily molded weld pool, complete fusion difficult to control & neat welds.
Rightward or Backhand welding Technique
In rightward Welding, the welder guides the welding torch in a straight line and moves the rod in a circular motion (the welding rod follows the welding torch). The welder holds the welding rod in the left hand and the welding torch in the right hand while moving the welding torch from the left to the right direction. As we can see in the below picture, welding starts from the left side and finish on the right side. The torch heat is directed towards the finished weld, so the weld appearance usually has temper colors. The welding direction is opposite to the leftward welding technique.
The Rightward welding technique gives keyhole welding and is thus suitable for welding thick plates more than 6 mm without any groove preparation.
- Targeted heat input,
- Ensured complete fusion,
- Lower cooling speed
- Better protective effect of flame.
- Difficult to use below 3 mm workpiece thickness.
- High requirement for the manual skill of the welder.
Joint Preparation for gas welding
The type of joints such as square or groove weld can be decided by the type of gas welding technique used. For example, leftward welding is suitable for thin plates but requires groove preparation for 2 to 6 mm thickness. While rightward welding technique can be used without groove preparation for higher thickness too. The below table shows the recommended welding joint preparation for gas welding.