Executive Summary:
Structural steel contractor Coastal Steel Inc. does away with stand-alone machines and reduces fuel use, clutter and hassle with the Trailblazer® 302 Air Pak™ combination welder/generator/air compressor.
- Easily powers shear wrenches and other power tools off generator power.
- Air compressor easily operates button punches, chipping hammers and roof fastening systems.
- Stick (SMAW) and Flux Cored (FCAW) capabilities critical to structural steel erection and deck installation.
- The new Auburn Professional Plaza in Auburn, Wash., is 500 tons of structural steel squeezed onto a postage stamp. The four-story building will house some of the City of Auburn's offices, as well as medical and banking facilities. The 88,000 square-foot structure is built onto one existing downtown city block. Its construction includes 738 bar joists, 60,000 sq. ft. of composite floor deck and 28,000 sq. ft. of roof deck.
Coastal Steel Inc. (Tacoma, Wash.) erected every piece of steel on the site. Such a job typically requires a fleet of welders, generators and air compressors to run all the tools necessary to erect steel; everything from shear wrenches to button punches and pneumatic chipping hammers. As one of the first companies to commission Miller's Trailblazer® 302 Air Pak™-a combination welder, generator and air compressor-Coastal Steel discovered that two of these machines gave them the power to run all of its tools and to reduce the clutter of equipment on the job site. It also reduces the overhead related to multiple machines and the associated maintenance/depreciation.
Steve Price and Chad Hummel (Coastal Steel) discuss the Auburn Professional Plaza in Auburn, Wa.
"When you only have to move a single unit from job to job, you have obvious cost savings in labor and fuel," says Steve Price, president, Coastal Steel. "The less you have on site, the less cluttered things are, and the less equipment you have to secure at night to prevent theft. Having this one unit makes obsolete the other individual pieces of equipment. And it doesn't take any more fuel to run than just a stand-alone welder, yet you've also got the compressor and generator functions."
Raising the Structural Steel Skeleton
Coastal Steel specializes in structural steel erection up to four stories. These structures are secured using a combination of high strength tension shear bolts (or TC bolts) and welding. A TC bolt has its own built-in torque control. Its torque requirements are achieved by engaging both the bolt and nut with sockets and driving it with an electric counter-rotating shear wrench until the control groove shears off. Once secured, the joints are welded to their support using either the Stick (SMAW) or Flux Cored (FCAW) welding process, depending on location and the style of the joint.
Hummel welds a diagonal moment brace using the Flux Cored welding process. Flux Cored is preferred for wire welding in the field for its high deposition rates and self shielding.
Instead of having numerous machines scattered around the jobsite, field superintendent Chad Hummel centrally-locates the welder/generator/air compressor to let his welders and bolt-upmen work simultaneously off of one machine. The moment welder also runs a pneumatic chipping hammer to remove slag between each pass, thus allowing all three of the machine's functions to work concurrently.
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Having a combined welder/generator/air compressor lets multiple workers work from the same machine. Here, Hummel is elevated with Miller's SuitCase® X-TREME™ 12VS wire feeder and a pneumatic chipping hammer, both which run back to the Trailblazer 302 Air Pak.
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"We'll pull a 12/3 power cord off the Air Pak's generator to run the shear wrench," explains Hummel, "And while one guy is doing that, you can run a pneumatic button punch and weld at the same time. All of that can go on if you have a unit centrally-located and enough air hose and welding lead to reach."
A typical electric shear wrench consumes a maximum 1,400 watts of power. The Trailblazer 302 Air Pak's 13,000 watts of Accu-Rated™ peak generator power gives it more than enough power to simultaneously run the shear wrench or other electric tools, including grinders, drills, impact wrenches and screw guns. Hummel and his crew are able to weld and run power tools with no loss in efficiency due to the machine's two separate generators. One generator powers the welding arc while the other provides usable electricity.
"It will not draw down your welding volts when using the generator," says Hummel.
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| Coastal Steel field superintendent Chad Hummel welds a diagonal moment brace on the ground floor of the Auburn Professional Plaza. |
Coastal Steel matches the Trailblazer 302 Air Pak with a SuitCase® X-TREME™ 12VS wire feeder for flux cored welding. A typical flux cored weld is a CP-joint connecting a ¾-in. thick beam to a ¾-in thick plate on a column of the brace frame (both Grade 50 steel). The root opening is 3/8-in. with a groove angle of 30 degrees. Setting the welder between 225 and 280 amps, the operator uses a .072-in Fabshield® XLR-8™ (E71T-8) filler wire from Hobart Brothers to make multiple passes to fill the joint. Slag is chipped away between each pass with a pneumatic chipping hammer, and Hummel uses the machine's air carbon arc gouging capabilities to back gouge the weld. He'll use either a ¼- or 5/16-in. carbon rod to back gouge after the copper backing bar (used to provide solid baking to the weld) is removed. This removes any foreign material in the root.
Hummel switches over to the machine's Stick capabilities for fillet welds, such as when welding the bar joists to a beam or to joist girders. This typically involves joining ½-in. steel plates with an E7018 electrode. The machine is set between 135 and 170 amps if using a 5/32-in. electrode and 110-130 amps if using a 1/8-in. electrode.
"It's really a machine that someone who specializes in bar joists and deck erection can't be without," says Price. "The multi-process welding capabilities allow us to quickly switch from Stick to flux cored, and we're able to power all of our electric and pneumatic tools without any loss in efficiency."
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| Coastal Steel situates its Trailblazer 302 Air Pak at a central location on the jobsite, or elevates it to the floor they are currently working on, so that workers may simultaneously pull from its air, electricity and welding power. |
Floor and Roof Deck Requires All Machine Functions
Coastal Steel begins placing floor deck once each floor's skeleton is completed. The exact order/procedure for laying the floor and roof deck varies on each job and is detailed in the deck manufacturer's drawing. The sheets of composite deck are formed from galvanized rolled steel and account for 60,000 sq. ft. of the floor and 28,000 sq. ft. of the roof. Once the deck is laid and positioned, each deck sheet is tacked into place using pin guns. What happens next is often determined by weather-a common interference in the Pacific Northwest.
The typical specification is to puddle weld the deck to the support beams below it and to join the male and female ends of the deck first by crimping or button punching, and then, sometimes, additionally with a top seam weld. If rain interferes and makes welding difficult, the engineer can approve an alternate process of either crimping or button punching the seam and securing the deck to the supports with a ¾-in. pin fired into the structure by a .27-caliber Hilti powder gun. This can be done as long as the process meets the required pounds per linear foot (PLF, or shear load).
"There are different configurations based on the load that's required by the engineer at any given location on the floor," says Hummel. "For instance, the perimeters are subject to more wind uplift and sheer than the interior of the building is. So there's a matrix of things that the engineer uses to determine the amount of welding, crimping and punching."
Having the flexibility to quickly switch between each process-and to run them simultaneously-is a major benefit to Coastal Steel.
"When we're welding down the roof deck, we can be simultaneously button punching as we go," says Price. "There's no longer a need for a compressor and a welder, thereby saving the cost of transporting two machines and the fuel to run those two machines. It uses virtually the same fuel while both operations (compressor and welder) are working."
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| Hummel uses the pneumatic Gator Grip to crimp together the male and female ends of 18-gauge floor deck. Whether welding, crimping or using a button punch, the Trailblazer 302 Air Pak powers most of the deck installation. |
When welding floor and roof deck, Coastal Steel relies on puddle welding (or burnthrough spot welding) to join the deck to the steel structure below. This Stick welding process involves striking an arc on the deck surface and forming a hole in the deck. Electrode filler metal is transferred into the hole and joins the deck to the support structure below. This process is carried out with a 1/8-in. E6022 Stick electrode with the welding settings between 150 and 180 amps. The machine's welding output (300 amps DC/250 amps AC) is more than enough to handle the job.
For air tools, the machine offers Coastal Steel 26 CFM (70 to 160 PSI) of air at 100-percent duty cycle-more than enough air to run its pneumatic tools used in floor and roof applications. A pneumatic button punch only requires 4 CFM and 100 PSI. It also easily operates Pneutek Inc.'s roof fastening system. The basic deck crimping tool only requires 15 continuous CFM. Hummel will even split the air supply so that one guy can button punch while another guy uses a chipping hammer. All of this without causing any lag in the machine's welding or power generation capabilities.
"When you have the constant air supply being provided by the rotary screw compressor, it has more capacity than any of the tools require," says Price. "These crimpers and punches are all designed to run off of small portable compressors. This machine gives us the option to run two or three tools, all at the same time."
Coastal Steel's Trailblazer 302 Air Pak is also outfitted with a fully-integrated air cooler/separator that removes 70 percent of the humidity from the air used to power pneumatic tools. In wet regions where winter temperatures reach or drop below freezing, such as the Pacific Northwest, moisture in the air supply can wreak havoc on tools.
"The air dryer takes out the humidity," says Hummel. "Our pneumatic pin gun was freezing up on us during the winter with our old compressor, so you'd have to add a drying substance to it. This machine doesn't have that issue."
Conclusion
The Trailblazer 302 Air Pak simplifies equipment management and lowers fuel use compared to operating both a stand-alone compressor and a welding generator. It lowers your overhead by hundreds upon thousands of dollars in cost related to purchasing separate generators and air compressors, and reduces the amount of depreciable equipment (and related maintenance) in your fleet. As one of the first contractors to use the combination welder/generator/air compressor on his site, Steve Price sees a clear benefit for its use in structural steel erection and floor/roof deck installation.
"This Trailblazer 302 Air Pak is like nothing else out there that we are aware of," says Price. "You get the versatility of multiple uses from one self-contained unit as well as an economy of fuel. It's extremely useful in our business model."
"As long as you're out of state, it's an absolute must," he says with a laugh. "If you're working in our area, don't do it. I don't need the competition. Just keep doing it the old way."
SIDEBAR:
Helping Design the Perfect Machine
Miller sees its Trailblazer 302 Air Pak-a combination welder/generator/air compressor-as a machine that benefits the construction industry as a whole by allowing contractors to reduce the size of their equipment fleet without losing any function. Structural steel contractors, however, can take special pride in knowing that one of their own had heavy input into its design.
"We showed Miller the type of equipment we use," says Steve Price, president, Coastal Steel. "They brought out a prototype machine and we brought out a button punch and some floor deck and I showed them what we do."
From that meeting, Miller decided to work with Coastal Steel and Pacific Welding Supply to ensure that the machine met the needs of a structural steel contractor. Air output, welding power, generator capacity and engine horsepower were all built-in to satisfy the varying demands of steel erection.
"Coastal Steel offers a perfect combination of needs to design a product like the Trailblazer 302 Air Pak," says John Powers, welding sales, Pacific Welding Supply. "Regardless of the stage of the project, these guys always need welding, power and air. The design of this product gives them one machine to replace two or three. That's a substantial savings in overhead cost, maintenance and labor."