4f Welding Position Full Patched Jun 2026

| Defect | Appearance | Root Cause | Solution | | :--- | :--- | :--- | :--- | | | A groove melted into the vertical plate just above the weld toe. | Welding too hot; pausing too long on the vertical plate; wrong angle. | Reduce amperage. Tighten the weave. Pause less on the vertical side. | | Lack of Fusion | The weld metal doesn't bond to the vertical plate. | Too cold; moving too fast; poor technique. | Increase heat. Slow down. Ensure you are washing the puddle into the vertical plate. | | Convex (Ropy) Weld | The weld bulges outward like a rope. | Travel speed too slow; amperage too low. | Increase amperage or move faster. Pause on the sides to flatten the center. | | Slag Inclusion | Slag trapped inside the weld (SMAW/FCAW). | Not cleaning between passes; weaving too wide; welding over slag. | Grind every pass. Keep weave width under 3x electrode diameter. | | Overlap | Weld metal rolls over the base metal without fusing. | Too cold; improper angle (pointing down instead of into the corner). | Increase heat. Adjust electrode angle to 45° into the corner. |

"4" designates the overhead position, and "F" designates a fillet weld. 4f welding position full

In the 4F welding position, the weld is made on a vertical surface, and the welding gun or torch is moved in a horizontal direction. This position requires a high level of skill and technique, as the weld pool is subject to gravity, which can cause the molten metal to sag or run. | Defect | Appearance | Root Cause |

A drag (backhand) technique is usually preferred to help prevent metal from running ahead of the arc. Tighten the weave