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Gas Engine Driven Welding Generator Lowers Costs, Improves Portability for Tilt-Up Contractor

Executive Summary

Miller Electric Mfg. Co.’s Trailblazer® 302 engine drive provides constant uptime and reduced equipment investment cost for Welding Dynamics of Norco, California. The Trailblazer® 302 matched with SuitCase® 8VS and 12VS wire feeders provide the following benefits:

Tilt-Up Construction Improves Productivity and Reduces Downtime

In the world of hard money welding, making money means getting the job done for less—period. In an aggressive, competitive bid situation, contractors must weld faster, try harder and use the most efficient equipment to win. Tom Lane, owner of Welding Dynamics, Norco, Cal., understands what it takes to win, and it’s more than his competitive spirit. For Lane, who welds an average of 40 to 50 tilt-up buildings a year, beating his competitors also requires having experienced operators and powerful, reliable welding generators and suitcase wire feeders from Miller Electric Mfg. Co. Downtime is not an option.

Tilt-Up Construction

Tilt-up concrete construction began in southern California in the late 1950s and continues to account for nearly 90 percent of industrial construction in California, as well as 75 percent of all industrial buildings in the United States. “Tilt-up” construction is used to describe a rapid, economic method for casting and lifting the exterior concrete walls of large industrial buildings, typically warehouses, distribution facilities, manufacturing plants or any number of buildings up to four stories tall.

Using the new Trailblazer 302 engine drive, Welding Dynamics operator Julio Pena flux cored welds a splice plate to join two sections of this tilt-up building. Note the fully enclosed case, SunVision digital meters and super-tough Xenoy faceplate.

First, slabs of concrete are cast in casting slabs and allowed time to gain sufficient strength, usually a week to 10 days. The slabs weigh 40 tons or more and measure only 6 to 8-in. thick. The concrete slabs are then lifted by cranes onto prepared foundations and temporarily braced so that welders can make structural weld connections on the panels. Notably, Lane welded the heaviest panel ever lifted by a single crane, a 150-ton, 51-ft. wide x 42-ft. high x 12-in. thick wall panel for a distribution center in Ontario, California.

In order to connect the panels, steel channels and angles are attached to the concrete with Nelson studs. The studs are fastened to the back of the channel and are cast in the concrete; the 3/8 in.-thick channels are effectively embedded. Lane then uses a steel plate to form a spliced plate weld connection between the two panels. Some plates may have seat landings that extend from the top or bottom of the plate, depending on where the bar joists need to be placed for the roof structure.

From the floor to the roof, the building shell is often completed in as little as four weeks, but the welding for the building often needs to be done in as little as a day, leaving a very small window of opportunityfor Lane to produce. Considering Welding Dynamics employs only three welders, including Lane, the window becomes even smaller. However, when the job is for Oltman Construction Company, the largest producer of tilt-up buildings in the United States, Lane can’t afford to miss it.

“I started working with these people in 1999, and it’s just constant work and continuing to prove your productivity,” says Lane. Particularly when working with Oltman, who puts up approximately 125 buildings a year, Lane realizes the importance of efficiency in tilt-up construction. On just one property in Valencia, California, Lane worked on 18 Oltman buildings, and in May of 2004 alone, Lane had 22 building starts.

To be profitable, tilt-up contractors need to weld more than 1000 inches a day. However, Lane welds approximately 1500 to 1600 inches a day and attributes his speed to his experience, effort and superior equipment. Because it’s a structural weld connection, not to mention that it’s performed in one of the most active earthquake areas in the United States, it must meet seismic standards and adhere to AWS D1.1 (American Welding Society Structural Code). For seismic applications, AWS D1.1 requires welders with CV (constant voltage) output, so contractors with welding generators that only have CC output might consider upgrading to a CC/CV machine.

Welding Dynamics operator Julio Pena uses Miller’s SuitCase 12VS wire feeder to make a 5/16-in. fillet weld on this landing, which will support a joist for a tilt-up building. The splice plate holding the two sections together is directly above it.

Tilt-up welds are made using “seismic” wires, which means they must have certain mechanical properties for use in seismic applications. The wires must be used within specific parameters to get good results. Lane, who runs self-shielded flux cored wire all day long, requires a welding generator that provides 1) sufficient power, 2) consistent output 3) premium CV arc performance and 4) durability and portability.

Two Welder System

For an Oltman job in Valencia, Lane tacks the splice plates in place and makes the flat position welds with his Miller Big 40G, an engine-driven welding generator with a 400-amp output. The Big 40G allows Lane to jump up to 400 amps using 5/64-in. E70T-7. E70T-7 wire is designed to give welders peak performance at higher amperage and voltage settings while maintaining excellent arc stability and high deposition rates. In short, Lane welds fast.

After Lane makes the flat welds on the steel splice plates, which are 20-in. wide x 8-in. high x 7/8-in. thick, one of Lane’s operators, Julio Pena, then comes in behind Lane to do the out-of-position welding (sides and bottom of the plate). Pena uses Miller’s new Trailblazer® 302, an engine-driven welding generator that provides a CC/CV, AC/DC output of 300 amps, 25 volts at 100 percent duty cycle. Compared to the previous model (which has been considered the best machine in its class for nearly 20 years), the Trailblazer 302 provides even better flux cored welding arc starts and a more stable welding arc.

Pena uses .072-in. E71T-8 wire to perform the vertical-up welds because the out-of-position welds require a smaller diameter wire that will produce the bead profile specified by the construction engineers, a 5/16-in. fillet weld, at the fastest possible travel speed. The fast freezing slag of this wire supports the high deposition rate on Pena’s vertical-up welds. The Trailblazer 302 provides Pena with the power he needs to obtain good penetration on the structural weld connections.

“With deep penetration welds, you need a lot of heat,” says Pena. “On other jobs, I have run this machine at 290 amps all day long without a problem.” In total, Pena has more than 650 trouble-free hours of welding with the Trailblazer, most of it at 250 amps or more.

Dependable Output

Because he’s running voltage sensitive wires in the hot California sun, Pena needs a power source that will ensure consistent output throughout the day. With the Trailblazer 302, which has its welding power rated at an ambient temperature of 104 degrees F, Pena doesn’t worry that output will drop if the machine gets hot—it doesn’t. As a result, he is able to weld all day without having to get off the telescopic boom lift to adjust the voltage. For a tilt-up job that must be completed in one day, every minute counts.

The new Trailblazer stays cooler than other engine drive because it features a fully enclosed case with a redesigned airflow system that keeps the internal components cooler. For truck mounting his machines, Lane sees a big improvement.

“We like that the air exhaust is discharged upwards from the back, top part of the machine. That eliminates problems with overheating when the machine is truck-mounted because the air can’t re-circulate,” says Lane. “Compared to the previous model, the Trailblazer 302 seems to be a little stronger at the end of the day.”

For high productivity welding on tilt-up buildings, Welding Dynamics uses a two-person set-up. Owner Tom Lane (with the Miller BIG 40G) runs 5/64-in. E70T-7 flux cored wire for the tack and flat position welds, then operator Julio Pena (with the Trailblazer 302) follows behind him, using .072-in. E71T-8 wire for the out-of-position welds.

For further accuracy, the Trailblazer has digital meters that display preset amperage or voltage when not welding and actual amperage and voltage while welding. When welding stops, the meters will display actual readings that are visible for up to 5 seconds, permitting Pena to see exactly what he’s burning during and after his welds. For the vertical-up connections, Pena’s desired welding parameters are approximately 23 volts and 260 amps.

“When I let up on the gun trigger, the last reading holds. That feature is dynamite,” says Pena.

To further enhance visibility, the new Trailblazer 302 features SunVision™ digital meters, which are readable up to 25 feet away in direct sunlight.

Another feature Lane likes is the machine’s quieter operation. “Quiet means less tension at the end of the day,” he says. “Also, we’re not the only ones on the job site. Now, communication is easier and we can hold a comfortable conversation.”

Durability and Portability

Lane knows the difference between a great deal and a great machine. If he uses a great machine, he produces more, and in the business of hard money welding (as opposed to billing a job based on time and materials), it’s that simple. He runs his Trailblazer hard and believes it runs better as a result. With only two employees, he can’t afford any breakdowns.

“You can’t save money by struggling to make something work that just isn’t good enough,” says Lane. “A great deal is no compensation for buying an inferior machine.”

In fact, not too long ago, one of Lane’s Trailblazer 301Gs went on a road trip—quite literally. In Lane’s eyes, the machine came out the winner. After one of his guys fell asleep at the wheel on the road to a job in Las Vegas, the machine was catapulted out of the truck and sent cartwheeling down the freeway at 60 mph. Both the driver and the Trailblazer survived with minimal injuries. Lane is still welding with his Trailblazer.

The new Trailblazer 302 gives Lane even more confidence. At first, he was skeptical of the machine’s Xenoy® cover, believing plastics wouldn’t hold up. Now, he’s convinced that plastics provide the strongest option for protection. “When I initially see plastic, I think it’s going to break, but I think it is a great upgrade over previous models,” says Lane.

Lane also likes the Trailblazer’s portability compared to larger diesel engine drives. Because insurance will only cover his equipment if it’s physically manned or completely fenced and locked in, he must transport his equipment on a daily basis. He learned this lesson, once, when two of his machines were stolen from a job site. As a result, he has a custom built truck with an auto crane that can easily lift the machine on and off the truck.

“Some machines are so heavy that you have to leave them on site, and then they are susceptible to theft and vandalism,” says Lane. “Instead, with these Trailblazer 302s, you can throw three or four in a pick-up truck and head down the road with complete security every night because your machines went home with you.”

Hard Money

Lane is always thinking ahead. When he bought his first truck, he was uncertified, unlicensed and uninsured. His first job didn’t work out very well, so with the little money he made, he hired a private welding instructor and became certified. Unfortunately, he let his license expire just a few months prior to the Northridge earthquake in 1994. Another lesson learned.

“During one of the hottest times in Los Angeles for welding, I was uncertified,” Lane says. “I was so angry at myself that I went and got every welding certification that the city of Los Angeles had to offer for manual and semi-automatic welding, and went and picked up additional AWS certifications. I used that experience to motivate me.”

However, Lane has been motivated from day one. When he started Welding Dynamics in 1990, his partners were going to be the labor end of the business, and he planned to handle the financial end. Within two weeks, he fired everyone.

“They were non-investing partners, and unless you have someone’s money involved, you don’t have their heart,” says Lane. “Where your money is, so is your heart.” With Lane, it just might be the other way around.<-->

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