Seven years ago, Lyle Proctor started DDJ Welding, Enumclaw, WA, a firm specializing in welded steel pipelines for the water industry, including hydroelectric dams, local water lines for utilities, pen stocks and power houses. In addition to himself, Proctor regularly employs four or five other welders, equipping them with completely outfitted work trucks. Some years, however, demand increases to the point where as many as 15 welders are needed.
DDJ Welding has Miller Electric Trailblazer 275 DC gas engine-driven welders on two of its trucks. With a peak generator output of 10,500 watts and a welding output of up to 325 amps (300 amps at 100% duty cycle), the units can weld with larger diameter electrodes and gouge with larger carbons (up to 1/4 in.).
"We run a lot of 5/64-in.-diameter E71T8-K6 self-shielded flux cored wire," says Proctor. "On larger diameter pipe, from 48 to 96 in., we will have an arc-on time of 15 to 20 minutes as we weld from the top down to the bottom of the pipe. Our Trailblazer 275, with its 100% duty cycle output, handles those long welds without a problem."
The gas engine drives have proven cost effective. In addition to their lower purchase price, they are significantly lighter than diesel engine drives. This enables Proctor to run 1-ton trucks instead of 1 1/2-ton units. His new Dodge 3500 chassis with 9.5-ft. flatbed cost him about $15,000 less than his older, heavier vehicle.
The lower gross vehicle weight enables Proctor to spec the trucks with a quad cab option. "Since we're on the road all the time, the large cab comes in handy for carrying extra gear," he says. "The 1-ton trucks ride a little smoother, too, which is nice for our guys."
Less weight also makes it easier to meet weight restrictions. "Sometimes we'll run 200 to 300 lbs. of wire in a week," he says. "For one guy to pack that much wire, plus all our other tools, we would really push weight limits by adding a 1,500-lb. diesel welder to the truck. Fortunately, a 600-lb. gas engine drive gives us a huge weight advantage."
Flux cored vs. stick
DDJ Welding wins most of the bids it submits because it completes jobs faster - without sacrificing quality - by using equipment designed for flux cored arc welding in construction applications.
Historically, pipe welders and contractors welding in the field have preferred the stick welding process. But stick welding literally sends profits up in smoke.
"With an E6010 electrode, only about 60% of the electrode mass transforms into the actual weld metal," says John Powers, outside sales, Pacific Welding Supplies/TEC Welding Sales. "The rest of the electrode mass is lost through stubs, evaporates into the atmosphere as smoke or chips off as slag. If you purchase a 50-lb. canister of stick electrodes, you only lay down about 30 lbs. of actual filler metal. Conversely, an E71T8-K6 flux cored wire yields a deposition efficiency of nearly 80%. This means you purchase less filler metal per joint, which increases your bottom line."
Stick welding is also an inherently slow process. A 3/16-in. E6010 electrode deposits about 2.6 lbs. of filler metal per hour. However, a 5/64-in. E71T8-K6 wire, with a wire feed speed of 110 in. per minute and an arc voltage of 20.5, yields a deposition rate of 5.5 lbs. per hour - more than a 100% improvement. Greater deposition efficiency can mean big dollars, since DDJ Welding often gets paid by the joint.
A recent water pipe job for the city of Tacoma involved 48-in.-diameter, 3/16-in. wall pipe welded to AWS D1.1 standards. The bell-and-socket joint required a 1/4-in. fillet weld on the outside of the joint.
Proctor put in a quicker stringer bead (root) pass to heat the pipe and take out any impurities, then put in a structural pass over the top, consuming the first pass and any pinholes that might have occurred. "The pipe required 12.57 ft. of weld, which I completed in about an hour," he states. Completing the same joint with the stick process would have taken at least twice as long.