By Clare Goldsberry, Associate Editor

Mobile welding is required for a variety of applications and settings from large jobs, such as high-rise building construction, bridges, and pipes that run through miles of open land, to small jobs such as fence-maintenance on a farm or ranch.

Portability is important even in factory settings when the job is too big to be moved to the welding shop, so the welder has to go to the job.

All of those factors and circumstances make portability key.

However, mobile welding also has unique challenges that include the need to receive power that is steady and reliable to produce optimal welds, and that power usually is provided by the engine of a maintenance or transportation vehicle. Also, the welding equipment often is exposed to harsh outdoor conditions that include rain and dust and the extremes of heat and cold.

Andy Becker, marketing and strategic planning manager for Climax Portable Machine Tools (www.cpmt.com), said the primary challenge to mobile welding continues to be equipment that is powerful enough to get the job done quickly. Additionally, that equipment has to be able to repeat welds when it’s called on to do so, and it should be capable of being automated.

Climax Portable Machine Tools assembles portable packages for customers in the mining, construction and heavy equipment industries, including welding service companies and equipment dealers.

“The challenge has been to automate the process and also make it easy to use. A lack of skilled welders and machinists means that customers want training as well, which we provide either here at our facility in Newberg, Oregon, or at the customer’s site,” Becker said. One of the specialty areas for Climax Portable Machine Tools is bore welding, in which automated welding equipment reaches inside the bore and welds it from one end to the other. Becker said that his company’s sales of portable welding equipment has grown 20 percent to 25 percent a year over the past several years, indicating a greater demand for mobile welding systems.

While mobile welding time is estimated to be less in comparison to the overall welding time for in-plant requirements, those who specialize in manufacturing mobile welding equipment say that demand for lighter, more versatile mobile welding products is strong.

“Demand for portable machines has never been higher. While there’s no doubt there’s more number of arcs performed inside than outside, outside welding is growing and has been very strong for many years,” said Joe Gitter, product manager for Miller Electric Manufacturing Co. (www.millerwelds.com).

Lyle Proctor, owner of DDJ Welding, found a niche for his company in pipe welding at construction sites and water treatment facilities, but the shop also has the versatility and skill to weld in many applications. Photo courtesy of Miller Electric Co.

Tony Blazina, president of Zena Inc., a maker of portable engine-driven welding equipment (www.zena.net), estimates that for every 10 hours to 20 hours spent welding in a shop, another 5 minutes to 10 minutes of welding is required in the field.

“Typically, when equipment or components (beams, girders, etc.) are installed, someone has to fabricate the final product at the installation location by welding at the job site,” Blazina said.

“Where mobile welding is concerned, for almost every piece of large equipment or a steel beam welded in a shop, installation requires at least some on-site welding for connection, erection or maintenance,” he added.

Welding takes place in a variety of environments from the factory floor to outdoor locations such as industrial structures and high-rise buildings, bridges, and long stretches of pipe, all of which require some degree of mobile welding capabilities. Which means generators and welding equipment must be transported to the job site.

Blazina said that Zena’s engine-driven, commercial duty portable DC arc welder can be attached to an engine of any vehicle from service trucks to farm tractors, to an ocean-going yacht or 4x4 off-road vehicle.

“New technology allows us to replace huge, engine-driven welding machines with generator packages so small and so light that there’s no practical reduction in vehicle payload, and virtually no loss of vehicle cargo space,” he said.

Miller’s Gitter added that there are a couple of issues that are driving the push toward smaller, lighter and more portable welder generator units.

“Fuel costs are driving this, as well as Department of Transportation regulations. Some companies are faced with DOT regulations that say if you drive a truck that over a certain tonnage, then the class changes, which means they are more heavily regulated, the drivers have to keep log books, and other requirements that become another hassle. So if they can reduce machine size and the carried weight, they avoid this,” Gitter said.

John Leisner, product manager for Miller, concurred: “The trend is toward smaller, lighter trucks, so they are demanding smaller, lighter generating and welding equipment. That means they are more likely to have a gas-driven welder generator.”

Zena’s backpack welder weighs 65 lbs and delivers 150 ADC at 100 percent duty cycle.

With smaller and lighter equipment, Leisner said companies now are more likely to send two people per truck, instead of one person per truck which used to be more common.

Additionally, many states require drivers of larger size commercial trucks to have a commercial driver’s license (CDL). Fewer people qualify for commercial driver’s license and, having this license means they earn more money.

“That one-ton truck often has two machines on it now, or one machine used for both welding and generating. They use the generator for grinding metal, cutting metal, and other tasks that often take longer than the actual welding,” Leisner said.

Another trend in portable welding is the migration toward generator power that is independent from welding power, so that other activities such as grinding or metal cutting don’t interfere with the welding arc.

Miller’s Trailblazer for example, can run two independent generators so that the operator can run a generator and weld at the same time.

“With some equipment, if you run a large enough power tool, the welder will see a slight change in the arc. That is the way nearly all small engine drives are, except for the [Miller’s] Trailblazer which has two generators inside one machine to produce 10,500W independent of the welding amperage, which improves the quality of the weld,” Leisner said.

“That makes it a true two-person machine – you can have two operations at one time,” he added.

Flexibility also is key when performing welding tasks in the field. Often a welder might not know exactly what type of welding will be required at the job site, so there’s a demand for the flexibility to do it all and do it well. Liesner said Miller’s Trailblazer product is more suited to run wire, but added that it can do a lot more.

In fact, Leisner pointed out that wire is more prevalent in mobile welding today than 10 years ago.

“It’s easier to run for some welders, but today’s welders run stick so easily that for many it doesn’t matter. Operators with less experience generally find it easier to run wire. Some-times with stick welding you have to stop. With wire you can do more, faster, and get more productivity. While there also are advantages to stick in the field, wire lets you put down more metal faster, so I’m seeing a trend toward wire,” Leisner said.

There’s also a trend toward DC TIG welding with a fairly high percentage of people in the field doing DC TIG welding.

While many people perform DC TIG welding, it’s not done very often in the field.

Leisner explained that one of the difficulties with performing DC TIG welding with portable equipment is filling the crater at the end of the weld, which typically requires a remote control hookup.

“To really end an arc you have to fill in the crater at the end of the weld, which requires the operator to ramp down the amps. In the field it’s a pain to connect a remote control device that runs along the ground where trucks can run over it. Because the wire is more fragile and easily damaged in the field, welders don’t like to use the remote control,” Leisner explained.

To help address this issue, Miller developed its trademarked “Auto-Crater” technology the Trailblazer welder generator. That technology allows the operator to ramp down the amps via a trigger at the torch rather than through a remote control device, which gives them greater control over the crater fill.

Zena also offers patented fingertip controls on its stick welders to allow operators to adjust power while welding. The company also addresses the weight issues in portable welding with its Backpak, which at 65 lbs., 150ADC 100 percent duty cycle, Blazina claimed is the smallest and lightest commercial duty welder on the market.

Manufacturers keep rising to the challenges of designing and developing mobile and portable welding that will meet the requirements of welders and the varied applications that confront them in the field.

Global demand is increasing as well. Gitter said as a global supplier, Miller is seeing stronger sales for its products in international markets, and technology advancements are driving new products.