Gas Engine-Driven Welder Generators Lower Equipment Acquisition Costs; Flux Cored Welding Improves Deposition Rates and Efficiency for Utility Contractor

Gas Engine-Driven Welder Generators Lower Equipment Acquisition Costs; Flux Cored Welding Improves Deposition Rates and Efficiency for Utility Contractor

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DDJ Welding relies on Miller gas engine drives to lower the overhead and operating costs compared to diesel engine drives; switching from Stick to flux cored welding offers a deposition efficiency of 80 percent and increases deposition rates by more than 100 percent.
Published: March 1, 2008
Updated: July 25, 2018

Executive Summary

  • Buying a gas engine drive saved DDJ $8,000 per welder compared to a diesel model.
  • Trailblazer® 275 DC provided more welding and generator output compared to competitive models.
  • Smaller, lighter engine drives (compared to diesel models) allows contractor to buy one-ton trucks with a quad cab instead of larger 1.5-ton trucks.
  • Today’s gas engine drives allow contractors to weld with larger diameter electrodes and gouge with larger carbons to maximize productivity.
  • Flux cored welding improved deposition efficiency and deposition rates over Stick welding in DDJ’s applications.

The Right Tools For the Job: Get the Most From Your Equipment Purchases

Can you imagine an independent contractor, steel fabricator, pipeline welder or mechanical contractor who refused to own a mobile phone? Ten years ago, that might have been an option, but today, refusing to keep pace with technology is the first step toward retirement.

Because welding equipment can last for decades, contractors often fall prey to the, “If it ain’t broke, why fix it?” mentality. Unfortunately, contractors who aren’t willing to examine new welding technology—“that ol’ diesel welder still runs a Stick rod like a dream” is a common excuse—may put themselves at a disadvantage during the bidding process and reduce their profit margins.

To help contractors improve their business, especially those that work from a service truck, three industry experts recently agreed to share advice. They all agree on two key points: whenever possible, shift from large diesel to small gas engine drives and use the flux cored welding process instead of Stick.

A Man and His Trucks

Lyle Proctor started DDJ Welding seven years ago in Enumclaw, Wash., which is about 20 miles east of Tacoma. DDJ Welding specializes in welded steel pipelines in the water industry, such as for hydroelectric dams, local water lines for utilities, pen stocks and power houses. In addition to welding himself, Proctor consistently employs four or five other welders, equipping them with completely outfitted work trucks. Some years, summertime demand increases work to the point where Proctor needs 15 welders.

Lyle Proctor, owner of DDJ Welding, reports that the digital meters on today’s portable “suitcase style” wire feeders are more user-friendly and precise than analog meters.

Bob Hankel, director of outside sales, and John Powers, outside sales, work for Pacific Welding Supplies/Tec Welding Sales. Where many welding supply distributors try to serve any and all markets, the Auburn, Wash., location of Pacific Welding Supplies/Tec Welding Sales focuses on serving a niche market: contractors, Ironworkers and others in the construction welding industry.

“Our job is to stay on top of industry developments, understand contractors’ needs and keep them competitive in the marketplace,” says Hankel. “One such development is the newest generation of gasoline engine-driven welding generators. By introducing DDJ Welding to these products, we helped lower welder acquisition costs by more than $8,000 per welder.”

Less than 10 years ago, “twin cylinder” gas engine products were powered by a 16 HP engine. Today, welding generators such as the Trailblazer® 275 DC and Trailblazer® 302 feature a 23 HP Kohler or a 22 HP Robin gas engine, and more powerful engines provide stronger welding and generator power output.

With a peak generator output of 10,500 watts and a welding output of up to 325 amps (300 amps at 100 percent duty cycle), today’s gas engine drives enable contractors to get more work done. They can weld with larger diameter electrodes and gouge with larger carbons (up to 1/4 in.), which maximizes productivity.

“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 inches, we’ll 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 percent duty cycle output, handles those long welds without a problem. I tried welding with a competitor’s twin cylinder engine drive, and I burned the guts out of them in 1,000 hours.”

The rugged polypropylene case of this portable feeder has obviously taken a beating, but it keeps the sand out and keeps on welding…a good thing considering that DDJ Welding is getting paid by the hour for this Tacoma, Wash. water pipe project.

Given the state of technology available, Proctor had a choice of burning up the competitor’s gas engine drives or equipping all of his service trucks with four-cylinder diesel engine welding generators. While these diesel generators have a 400- to 500-amp output that delivers more than enough power for welding with larger electrodes (a necessity on some jobs), it also has drawbacks. Diesel welders are expensive; list prices start at $13,000. Four cylinder engines are heavy; they weigh 1,500 to 1,700 lbs. And they are large; on average, they measure 50 in. high x 30 in. wide x 64 in. deep.

In comparison, a 300-amp gas engine-driven welding generator costs less (list price is about $4,700), weighs less (just under 600 lbs.) and has a smaller footprint (33 x 20 x 45 inches).

“With smaller gas engine drives, I can run one-ton trucks instead of ton-and-a-half trucks, which lowers my gross weight,” says Proctor. “Also, I can get one-ton 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. The one-ton trucks ride a little smoother, too, which is nice for our guys.”

Using smaller trucks also saves money. Proctor’s new Dodge 3500 chassis with 9.5 ft. flatbed (see photo) cost him about $15,000 less than his older Ford F450 truck.

Finally, keeping gross vehicle weight below regulated limits remains a constant challenge for contractors, and small engine drives help.

“Sometimes we’ll run 200 to 300 lbs. of wire in a week,” says Proctor. “For one guy to pack that much wire, plus all our other tools, we’d 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.”

Currently, Proctor has Trailblazer 275 engine drives on two of his trucks. For guidelines on mounting a twin cylinder gas engine drive on a work truck, visit

Build to Last

Historically, some contactors preferred diesel engine drives because the engines would last about five times longer than gas engines. Now, however, gas engine manufacturers have improved the durability of gas engines to the point where they can be expected to last 4,500 hours with good maintenance. Diesels last, at most, only two or three times longer. Considering that a four-cylinder diesel engine cost three times as much as a twin-cylinder gas engine, plus the thousands of dollars of other savings, the rationale for using diesel engine drives just doesn’t add up in many situations, as the chart below indicates.

 *Diesel vs. gas engine, both welding at 150 amps @ 100% duty cycle

Stick Leaves You Stuck In the Bidding Process

DDJ Welding found its niche because the firm specializes in pipe welding at construction sites and water treatment facilities, but they also have the versatility and skill to weld in many applications (the Trailblazer has a multiprocess MIG/flux cored/Stick/TIG output and provides best-of-class arc performance in every process). The company wins most of the bids it submits because DDJ Welding completes jobs faster without ever sacrificing quality. How? Proctor uses equipment designed for flux cored arc welding in construction applications.

When welding out-of-position and using an auto-darkening helmet, be sure to choose a helmet with four sensors¾two above and two below the viewing window. This way, even any three of the sensors are blocked, the remaining sensor will ensure the helmet still darkens properly.

“Contractors that turn a blind eye to new technology seriously limit their firm’s capabilities, and they hurt profits,” says Proctor.

Historically, pipe welders and contractors that weld in the field have preferred the Stick process. Unfortunately, sticking with Stick literally sends profits up in smoke.

“With an E6010 electrode, only about 60 percent of the electrode mass transforms into the actual weld metal,” says Pacific Welding Supplies/Tec Welding Sales’ John Powers. “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 pounds of actual filler metal. Conversely, an E71T8-K6 flux cored wire yields a deposition efficiency of nearly 80 percent. 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 inches per minute and an arc voltage of 20.5, yields a deposition rate of 5.5 pounds per hour—more than a 100 percent improvement over Stick welding.

Weighing less than 600 lbs., this Trailblazer 275 DC gas engine drive takes up very little room in the back of a work truck. Note the protective roll cage with hangers for easy cable management.

For Proctor, greater deposition efficiency means big dollars: DDJ Welding often gets paid by the joint. On a recent water pipe job for the city of Tacoma (see photos), the project 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 he “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.” Completing the same joint with the Stick process would have taken at least twice as long.

In addition to being faster with flux cored welding, DDJ Welding also produces quality welds. In 2006, the company won a subcontract in Anchorage to weld 80 joints of 42-in. diameter pipe (3/4-in. wall thickness, V-groove, full penetration butt welds). Each joint on the high tensile strength pipe took 14 man-hours to complete.

“On the first day we arrived, we met with the engineering and project managers. Welding was at the top of their priority list,” Proctor recalls. “A few months later, welding was no concern. We completed all 80 joints—and every weld was x-ray inspected—with just one slag inclusion at the surface of the weld. We ground that out, repaired the weld and it passed x-ray. Other construction workers on the job couldn’t believe that we could flux cored weld so quickly and with such quality.”

A New Breed of Portable Feeders

“Although wire welding in the field is not a new concept, there is a new generation of suitcase wire feeders available,” says Powers. “These feeders offer wire feeding performance that matches bench-style shop feeders, a larger contactor rated at 425 amps at 60 percent duty cycle and a more durable case.”

The newest “voltage sensing” feeders can run gas-shielded and self-shielded solid and cored wires from .023- to 5/64-in. diameter. Because they have a much broader arc voltage range (14 to 48 VDC), they can run small and larger wires without arc outages or the “contactor chatter” common with older feeders.

From left to right: Bob Hankel, director of outside sales, outside sales, Pacific Welding Supplies/Tec Welding Sales; Lyle Proctor, owner of DDJ Welding; Don Knight, district manager, Miller Electric Mfg. C.; John Powers, outside sales, Pacific Welding Supplies/Tec Welding Sales

Proctor says that, “John [Powers] introduced me to the Miller SuitCase™ X-TREME™ 12 VS last year. I ran those feeders on the Anchorage job paired with Miller XMT® 350 inverters, and the welders just loved them. They ran perfectly.

“On another 72-in. pipe job, where we wouldn’t break arc for 20 minutes, the X-TREME’s trigger lock function was great. It stopped some of the hand fatigue related to keeping the trigger pulled. We could move around and change hand positions without stopping.”

Another feature Proctor likes of the newest portable wire feeders (and engine drives) are their digital displays.

“Before digital readouts, we set voltage and wire feed speed by feel,” he says. “We’d find a sweet spot and put a scratch mark on the face plate. The digital readouts add more precision, and each machine runs the same. There’s no more guesswork when setting welding parameters.”

Water, Mud and Sand

With its focus on water lines, DDJ Welding does much of its welding down in trenches and inside pipe (some procedures/codes require welds on both the inside and outside of a joint).

“We’re always around water, mud and sand,” Proctor says. “We try to tie the feeders off to make sure they don’t fall, but dirty environments are just a fact of life. So far, the SuitCase feeder has been very durable. We even had them submerged when we left them in a pipe overnight and someone opened a valve. As long as you open the feeder up and let it dry for a couple of days, it will be all right. Just don’t turn it on, or the moisture will cause it to short out.”

To withstand construction job site environments, portable feeders like the SuitCase X-TREME feature a case made from polypropylene—the same rugged material that the U.S. military uses to protect computer hardware—to shield the internal components of the feeder against sudden impacts and rough handling.

[To see a video of the abuse a Miller SuitCase X-TREME feeder can withstand—including being run over by a truck—visit

Worth the Effort

Empty, a portable feeder weighs 23 to 35 lbs., depending on the model, while a roll of welding wire adds up to 25 lbs. (the E71T8-K6 wire DDJ Welding uses comes in 14-lb. coils). Each of Proctor’s trucks is equipped with 450 ft. of lead (three 150-ft. lengths), using 3/0 cable for the ground clamp and 2/0 for the welding lead. To ensure 115 V power is available for running grinders, Proctor tapes a heavy-duty (12/3 SO) extension cord to the welding lead.

Proctor admits that some older operators “don’t want to deal with a wire feeder on the job site or carry a cumbersome feeder in their truck, but the production of a wire feeder is so much better than Stick welding, we feel its worth the effort. In fact, once you get used to carrying the SuitCase, it’s not a big deal. For added mobility in tight spaces, such as the inside of 36-in. diameter pipe, we created small wagons that hold the feeder, a 350-amp inverter, work lights and such. For working in trenches, we just lower the feeder in with a rope so we don’t have to worry about carrying it up and down a ladder.”

Buy the Best

With an overhead of $70 per hour per employee, Proctor wants his welders to be as productive as possible (remember: DDJ Welding gets paid by the joint). That’s why Proctor opted to purchase the newest generation of engine drives and wire feeders.

“You can rarely go wrong looking at new technology,” says Proctor. “You have to keep your eyes open to new developments, and that’s one of the advantages I get by working with Pacific Welding Supply/TEC Welding Sales. They have a diverse customer base and test a lot of different products. If a welder or feeder can pass the test of working in their rental fleet, then I know it’s a good product.

“My company’s slogan is, ‘quality will never be compromised.’ I tell my employees we do things right the first time,” states Proctor. “Better equipment results in better quality, and that’s how I justify my return on investment.”