Oxy-fuel welding in the vertical position requires a technique in order to keep the molten metal from running downward.

In vertical position welding, the axis of the weld is approximately vertical.

When welding is done on a vertical surface, the molten metal has a tendency to run downward and pile up. A weld that is not carefully made will result in a joint with excessive reinforcement at the lower end and some undercutting on the surface of the plates.

When using the Oxy-fuel welding process in the vertical position, the flow of metal can be controlled by pointing the flame upward at a 45 degree angle to the plate, and holding the rod between the flame and the molten puddle (fig. 11-14). The manipulation of the torch and the filler rod keeps the metal from sagging or falling and ensures good penetration and fusion at the joint. Both the torch and the welding rod should be oscillated to deposit a uniform bead. The welding rod should be held slightly above the center line of the joint, and the welding flame should sweep the molten metal across the joint to distribute it evenly.

 Oxy-fuel welding a butt joint in the vertical position.
Butt joints welded in the vertical position should be prepared for welding in the same manner as that required for welding in the flat position.