Note

Thick, gauntlet-type rubber gloves in good condition, worn over a pair of Playtex-type gloves afford the best protection against electrical shock. They should be secured at the wrist to prevent slag from getting inside the gloves. In cold water, wet suit gloves in good condition, worn over surgical gloves are equally effective.

E-2.5 Arcwater Electrode Cutting Technique. As always, before conducting any type of electric arc cutting underwater, a ground cable must be attached to the work piece. The diver can either leave the surface with the cutting torch, ground cable and cutting electrodes or they can be lowered after arrival at the work site. The first task is to clean a spot for the ground clamp. The spot should be in a position in front of the diver and should be scraped or wire brushed shiny clean. For diver safety, only C-type clamps should be used as grounding clamps for underwater cutting or welding operations. The clamp must be firmly secured to the work piece and the cable should have sufficient slack to prevent it from being pulled loose. The diver may elect to lightly tack weld the clamp in place when there is a possibility of it working loose. From time to time as the cut progresses, the diver may have to reposition the ground clamp to avoid becoming part of the electrical circuit.

E-2.5.1 Underwater Preparations. Insert the electrode into the collet opening until it bottoms out. Tighten the collet nut. To start cut, hold electrode perpendicular to the surface to be cut. Place tip of electrode against the work and call for water on and then SWITCH ON. If necessary, withdraw electrode slightly and tap it against the work to start the arc.

E-2.5.1.1 Cutting. For cutting, the torch should be held at a 75° angle with the water jet under the electrode. Care must be taken to prevent molten metal blow-back. Once a hole is pierced, proceed along the intended line of cut using a sawing motion Holes can be pierced in the same manner and enlarged using a sawing motion.

E-2.5.1.2 Gouging. The depth of the grove will vary with torch angle, travel speed, amperage and pressure exerted on the electrode. For gouging and weld removal, the torch should be held at a 40° angle to the work with the water jet under the electrode. The torch should be moved forward at a speed sufficient to maintain the arc and the desired groove depth. The diver should not cut deeper than 1/4" in a single pass. This will prevent molten metal from being blown back at the diver.

E-2.6 Material Consumption. Table E-1 is provided for planning purposes. It lists an approximate range of cut through various plate thicknesses up to 3/4-inch plate. Allowances should be made for diver proficiency and underwater conditions such as visibility, metal cleanliness and current.

E-2.7 Post-dive Maintenance. After each use, rinse the torch in fresh water and dry it. Disassemble and inspect for corrosion damage due to electrolysis. Replace any damaged parts as applicable. All equipment should be thoroughly dry before storing. Secure hose ends with caps or tape to keep out debris. Store all equipment, including electrodes, in an oil-free environment.

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