Stick Underwater Welding

Stick welding/SMAW is a commonly used, economical process for wet underwater welding. This process can be carried out in all positions with the same success as welding in air.

All electrical leads, lighting gear, electrode holder, gloves, etc must be fully insulated and in good condition. Ferritic electrodes with a coating based on iron oxide should be used as they resist hydrogen cracking.

Welding polarity is always DC. DCEN is preferred in order to keep 65-75% of the heat in the metal being welded. DCEP may have to be used for overhead butt welding or welding cracks in the vertical and overhead positions.

Current settings for underwater welding are normally higher than for welding in air, and the control of these settings must be accurate to ensure consistent work. Generally, the greater the depth of the water, the higher must be the machine settings.

When preparing the job before welding, all edges to be welded should be rough ground to fit and all paint and loose scale should be removed.

For striking the arc, the electrode is held at an angle of about 35-45 degrees to the surface of the plate and its end is struck against the plate. After the arc has started, the electrode is held on the plate and pressure is exerted to keep it there.

The arc length should be about the same as that for surface welding. The speed of welding, even in clear water, will be slower than the speed when welding is carried out at the surface.

The most common preparation for underwater welding is the fillet, which is, unfortunately, the more difficult of the joints to weld. Underwater fillet welds invariably require an oscillation, whereas underwater butt welds are rarely performed in this way.

The oscillation technique is achieved by raising and lowering the slope angle whilst welding. The oscillation occurs at the end of the electrode closest to the operator, so that the end closest to the workpiece remains a similar distance to the workpiece.

Slight oscillation of the electrode in this case gives more control over the weld pool and greatly assists the welder in producing a well shaped fillet.