There are basically 2 types of gas welding techniques used in Oxy Acetylene gas welding process.
- Forehand technique (or Leftward technique)
- Backhand technique (or Rightward technique)
These two types of gas welding techniques are classified according to the ways in which the welding torch and filler rods are used.
Let me tell you few important things about both the gas welding techniques.
#1) Forehand technique (or Leftward technique)
- In forehand welding technique, the torch is on the right hand side and the filler rod (or filler material) is on the left hand side.
- In forehand technique, the welding torch is kept inclined at an angle of approximately 65° from the weld surface and the torch moves in the direction of the welding.
- In this technique, the weld starts from the right hand side and it is directed towards the left side (away from the finished welded surface).
- Forehand welding technique is generally used for welding of material having thickness up to 5 mm.
- If the material has thickness of more than 3 mm, then “V” shaped groove is necessary to be made, so that the filler material penetrates to the bottom.
- Moreover, this technique is easy to handle, but the main disadvantage of forehand technique is, there may occur excessive melting of edges.
- The forehand technique is also known as leftward technique as the welding proceeds towards the left direction.
#2) Backhand technique (or Rightward technique)
- In backhand welding technique, the torch is on the right hand side and the filler rod (or filler material) is on the left hand side.
- The welding torch is inclined at an angle of 45° from the unwelded surface and the flame is directed towards the molten pool.
- As shown in the above image, the welding starts from the left side and proceeds in the right direction.
- Hence backhand welding technique is also known as rightward technique.
- Here the welding flame is faced towards the finished welded part and the position of filler rod is between the weld and the flame (see above image).
- You can also see in the above image that the angle between the filler rod and welding torch is approximately 90°.
- The main advantage of using backhand welding technique is that the molten pool is clearly observed during the welding process, and the fusion rate is also high.
- Backhand technique consumes less gas as compared to forehand technique.