Application Tips: Welders

Just because you’ve had success using a certain kind of welding machine in the past doesn’t mean you shouldn’t consider something different the next time you buy.

While it may seem counter intuitive to fix something that isn’t broken, you might miss out on advancements that could improve your bottom line if you don’t at least find out if the type of machine you’ve been using for the past 10 years is still the best for your applications. “Ask if there’s a better mousetrap out there you should be using,” says Neal Borchert, business development manager for Miller Electric.

New technology
Inverter technology has improved welders for construction use, making machines smaller and lighter weight, but with the same amperage, says Bruce Morrett, product manager for Hobart Brothers. Most welder manufacturers make key technological strides every two to three years. Knowing how the equipment has changed can help you decide whether upgrading makes financial sense.

Multi-process inverters, which allow you to stick, wire or TIG weld, typically weigh less than 100 pounds, so they can be moved easily, quickly and cost effectively. Many of these inverters can be configured in multi-operator “rack systems.” Compared to conventional multi-operator systems, which may weigh 2 tons and have to be moved with a crane, inverter racks weigh 300 to 800 pounds and can be transported in a half-ton pickup truck.

Features that were optional in the past are standard today. For example, digital meters allow you to set proper amperage and/or voltage levels, as well as view parameters from a distance. Digital meters also let workers confirm they are welding within specifications set by supervisors.

On welding generators, new standard features include covered weld terminals (to better protect against accidental shock) and low-fuel shutdown. On diesel machines, this eliminates the need to have a mechanic reprime the welder, avoiding costly downtime.

New high-quality electronic controls closely manage fuel consumption and sound levels, making welders more environmentally friendly without sacrificing performance, which has significantly improved in recent years, says Doug Miller, welder product manager for Multiquip. Better arc welding controls also allow operators to fine tune the arc to achieve higher quality welds more easily than in the past.

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In addition to not considering newer technology, failing to match equipment to the operator’s skill is a common mistake contractors make when purchasing. “You can purchase the most sophisticated and technologically advanced welder, but if the operator doesn’t possess the necessary knowledge to use it effectively, you’ve wasted money,” Miller says.

John Leisner, product manager for portable power, Miller Electric, says many of today’s machines have hidden technology advances that help people who are not as skilled make good welds. For example, newer welders have a “hot start” feature that can prevent a stick electrode from “sticking” during arc start. They also have adjustable stick arc force, or “dig” controls, that let operators tailor the arc force to match the application and type of stick electrode being used.

To enhance productivity, you might want to rethink the welding process you use, Morrett says. If you are going to be working on a large job and have stick electrode welding equipment, ask yourself if there is a way to upgrade to wire welding, a faster method. To determine whether the job justifies the equipment acquisition costs, Morrett says you should consider: the job’s size; the capital expense for new equipment; the time and expense of training operators (If someone can stick weld, teaching them to wire weld doesn’t take long.); and time constraints (Do you need to make an investment to get the job done in time?).

Before you buy…
If you are relatively new to buying welding equipment or haven’t made a purchase in awhile, here are some questions you should ask yourself.

Is there power at your jobsites? Most contractors prefer electric welders if power is available because they won’t have fuel costs. If you are working indoors, an electric welder is your best option (although some welding generators also have an LP fuel option). If you’re working outdoors or will be moving the welding machine around your jobsites a lot, you might want to eliminate the extension cord by using an engine-driven welder, even if power is available.

Do you need constant voltage or constant current welding capability? Stick or TIG welding steel require a CC machine, which can also be used for air carbon arc gouging. Any kind of MIG or wire welding, on the other hand, is best done with a CV machine, which is typically paired with a portable, “suitcase-style” wire feeder or a spool gun. Note that while flux cored welding can be done using a CC welder and a voltage sensing wire feeder, the arc will be more difficult to control. Also, many welding codes now explicitly require a CV welder when MIG or flux cored welding.

How much amperage do your jobs require? Heavy-duty applications such as welding structural steel might demand running large-diameter electrodes and gouging with big carbons. Welders that offer a top output of 350 to 600 amps at a high duty cycle rating work well in these applications. For lighter-duty construction such as fabricating components or mechanical work, welders with 40 to 300 amps of output will usually suffice.

To judge a plasma cutter’s capacity, use these guidelines:

  • A 25-amp machine will cut 3/8-inch steel.
  • A 55-amp machine will cut 7/8-inch steel.
  • An 80- to 100-amp machine will cut 1- to 1/-inch steel.

What duty cycle do you need? Duty cycle is the number of minutes out of a 10-minute period a machine can operate without building up too much heat internally. For example, a rating of 500 amps at 32 volts at 60 percent duty cycle means a machine can create a 500-amp-at-32-volts output for six continuous minutes out of 10 and then needs to cool for the remaining four.

How much generator power do you want? Engine drives can offer 3,000 to 20,000 watts of generator power to run lights, tools and even another welder or a plasma cutter. Single- and three-phase power options are available. Another thing to consider is if you’ll need generator power while welding. Some machines do this really well, so two or more people can weld or work from a single engine drive.

Do you want a lot of arcs in one area? If so, consider multi-operator welding systems. They reduce costs for transportation, maintenance and fuel, take up less space at the jobsite than several single-arc machines and require only one primary input.

How far will operators be from the welding machine? You might want to buy a remote control so they can fine tune the amperage without returning to the welder’s front panel.

Will engine noise be an issue? Quiet engine drives are available if you need low noise levels for jobs in urban areas or want to reduce noise-related stress on operators. An engine drive that produces 75 decibels at 23 feet is considered quiet. Since sound levels increase exponentially, a 3-decibel increase makes the engine drive 30 percent louder, while a 6-decibel rise causes the welder to be 50 percent louder.

Staying safe
The most common safety violations by welding equipment operators involve improper safety gear. Not wearing gloves or using a welding helmet with the wrong lens shade are two frequent transgressions, Borchert says.

Arc flash is a major safety concern, Miller says. You and your employees must wear the necessary eye protection to prevent eye injury as well as the proper clothing, gloves and boots to protect you from burns caused by sparks and hot metal. Also watch for the shorting out of cables or cables that are in poor condition. Bare spots in the wire can result in minor burns and other injuries.

If you or your employees need to wear a hardhat while welding, hardhat adapters that allow you to wear a welding helmet and a hardhat at the same time are available from most welding distributors.

New website offers welding-related business advice
Miller Electric launched a website in January to help contractors with welding-related business concerns.

The site uses profiles of specific projects to provide information in the top four categories requested by its customers: how to reduce costs, improve productivity, increase operator efficiency and justify purchasing new equipment.

“The answer to all these things really is new technology,” says Terri Barry, public relations manager for Miller. “For instance, to increase productivity and reduce welding costs, you often have to look beyond the arc to pre- and post-weld operations. Would different technology reduce the number of hours spent moving a welder to the jobsite or fixing weld flaws? Those are just some of the real issues the website addresses.”

A blog at the site allows you to share your point of view about welding issues and read advice from your peers and Miller employees. The website is at