Robert Yates has long been known as possessing one of racing’s sharper minds, especially given his ability to refine horsepower. For the past 30 years, he has built an impressive career and carved out a well-earned reputation as a premier builder of engines by working for such legendary drivers as Bobby Allison and Cale Yarborough. Now his own drivers—Dale Jarrett (#88) and Elliott Sadler (#38)—continue to set Yates apart from his colleagues and competitors in the professional stock car racing industry.

Located in Mooresville, N.C., just north of Charlotte, Robert Yates Racing (established 1988) carefully maintains its owner’s reputation for building quality engines and leading the pack in horsepower innovations. Not surprisingly, the quality fabrication for which Yates is famous starts in the chassis fabrication shop. Here, fabricators complete pre-body work, the type of fabrication that calls for high-integrity welding.

One thing that sets Robert Yates Racing apart from its competitors is that the team makes the majority of its chassis (about 15 per year) entirely from scratch.

The gulf widens even more from other teams because Yates’ fabricators rely on the GTAW (TIG) welding process to build the bulk of their chassis and reserve the more traditional GMAW (MIG) process for welding the floors and tacking up sheet metal. In either case, the team continues to rely on the welding technology offered by Miller Electric Mfg. Co., Weldcraft and Bernard to get the job done.

Homemade Quality from Scratch

Like any fabrication activity, building and modifying a chassis for Yates’ drivers involves multiple steps to ensure that the final product is of the highest quality possible. Joe Hoffman, manager of Yates’ chassis fabrication shop, explains why Yates insists on building “homemade” chassis, starting with all the sub-assemblies.

“Without giving away any trade secrets, there are certain qualities that our drivers and race teams want in a chassis, and we can achieve those qualities by designing our own,” says Hoffman. “Some of the things are weight-related, and some things are actually component-related, but either way, we can do it. If we bought a chassis, we wouldn’t have that advantage.”

That’s the same reason Yates’ chassis fabricators rely on the TIG process for the majority of their welding needs—precision and custom-made quality. The smaller components on the chassis and suspension require fabricators to craft exceptionally small weld beads, often underneath the car or in an equally awkward position. To maintain quality control, fabricators use Miller’s Dynasty® 300 DX AC/DC TIG welder (they also keep Dynasty 200s in the shop) with Weldcraft’s SF-225 Modular Flex Head Torch Package.

A Yates’ fabricator TIG welds the front frame support for the sway bar tube using his Dynasty 200. The machine’s advanced squarewave technology and ultra smooth DC creates strong, precision welds on each of Yates’ chassis.

The Dynasty’s advanced squarewave technology provides positive arc starts and superior arc stability, while the SF-225 allows them to get into tight or awkward angles. When welding aluminum, the Dynasty’s technology also permits more precise control of the weld puddle, bead width and penetration by allowing fabricators to adjust output frequency and extend balance control.

The Dynasty 300 operates on either single- or three-phase power and offers Yates’ fabricators a range of 5 to 300 amps. At the rated AC rated output of 250 amps at 30V, the Dynasty has a 40 percent duty cycle; for DC welding, the machine also provides a 40 percent duty cycle at a rated output of 200 amps at 28 V. Miller’s exclusive Lift-Arc™ technology allows fabricators to initiate the arc automatically without using a high frequency start, but they can also choose a non-contact, high frequency start if they prefer. A built-in pulser also helps reduce heat input to ensure clean, accurate welds.

“While MIG welding could complete the job faster when fabricating smaller components for the chassis or engine, our engineers decided that the precision and quality we get from the TIG welding process is more desirable,” Hoffman explains. “We save the MIG work for just the floors, our tack welds and eventually, skinning (or finishing) the cars.”

Precision Technology, Precision Welds

When TIG welding, Yates’ fabricators know that they need to compromise between working slowly at lower amperages (to keep the heat input down) and trying to complete the work in a timely matter. Moving too fast and using too much heat can distort the base metal, a problem that could seriously affect the structure and safety of the chassis. For example, when Brad Turner, a Yates team fabricator, uses his Dynasty to weld 1 ¼ - inch engine bar braces using a.040-inch diameter filler rod and 3/32-inch diameter tungsten, he needs to create a balance between speed and efficiency.

Fortunately, through years of experience, Turner can judge the amount of heat used just by the color of the bead when he’s finished welding. “I weld the outside of the bar first and then come back and weld the inside,” he explains. “It gets darker if I apply excess heat, so experience tells me to back off the foot control.”

Weldcraft’s SF-225 allows fabricators to choose the right torch head for the job. Here a fabricator TIG welds a sway bar tube to the front frame support.

The Dynasty’s balance control function also helps. By allowing Turner to fine tune a larger portion of the welding cycle toward EN (electrode negative), he can achieve better penetration and faster travel speeds without increasing his heat input and distorting the metal. As a result, Yates believes that TIG welding produces chassis with superior structural integrity. While exact numbers aren’t available for public knowledge, the deflection strength¾how many pounds of force it takes to move the chassis a given distance¾of a TIG welded chassis is greater than that of a MIG welded chassis. That’s not to say that MIG welding won’t produce a structurally sound frame, but Yates prefers to use that technique for other parts of the building process.

John Harvey, another fabricator in the chassis shop, spends a good deal of his time welding radiator overflow tanks located in front of the cars between the radiator and the motor. The tanks are 3 inches in diameter by 16 inches long, and they’re made of 3003 aluminum. “They’re a real pain to weld,” Harvey says. Fortunately, the Dynasty’s advanced squarewave technology provides greater control for a more focused, tighter arc, which is a critical feature when welding thinner [.040-in.] aluminum.

Using the Dynasty in combination with Weldcraft’s SF-225 torch packages also helps Harvey and Turner weld areas with limited access and eliminates the need to keep extra torches in the shop. With its flex neck and multiple torch heads, the SF-225 lets Yates fabricators create seven different torch configurations from an existing water-cooled TIG torch. Having that ability helps fabricators adjust to the many different welding angles and means less downtime for torch changeover. Harvey and Turner just need to change out the torch head instead of the whole torch, which helps them get the job of building the racecars done quicker.

“I like the combination of the Miller machine and Weldcraft torch,” Harvey says. “I can change the AC arc characteristics as much as I need to, from 50 to 90 percent electrode negative on the balance control and 20 to 250 Hz on the output frequency and tailor the arc cone width to the application. And these are butt welds, not overlapped, so all the fits have to be right there. Having an easy option for controlling the weld bead and switching out torch heads to weld those joints definitely helps.” Harvey also uses the Dynasty and SF-225 to weld .090-in. chrome-moly control arms. He limits the amperage control to about one-third of the Dynasty’s total amperage output in order to get better resolution out of the foot pedal. As the amperage slowly increases and the weld puddle forms, all the impurities go to the top of the weld. Harvey explains that he also keeps his torch and filler rod in position after he finishes welding, because the post-flow shielding gas improves weld quality and reduce contaminants, both factors essential to creating top quality welds on the Yates’ chassis.

TIG welding also creates a more aesthetically pleasing weld, another reason why the Yates’ team relies on the superior TIG welding capabilities of the Dynasty. “Obviously, you can’t see all the welds in a race car, but we take a great deal of pride in our work, and that includes how it looks,” Hoffman says. “Besides providing outstanding structural integrity, the stacked dime appearance of a TIG bead looks better, too. That’s important to us.”

It’s important to the many of the Robert Yates Racing fans out there, too. Whether they think about it or not, sound welds mean sound performance and that means winning cars season after season.

Despite their fondness of TIG welding, the Yates’ team does weld about 10 to 15 percent of their racecars using the MIG process. With the help of Miller’s Millermatic® 210, which provides a welding range of 30 to 210 amps and a 60 percent duty cycle at the rated output of 160 amps, 24.5 V, Yates’ fabricators can adjust to the parameters needed to tack weld parts, weld the stitch floors and fit the body to the chassis (also called ‘skinning’).

For tacking the interior sheet metal on the rear clip of the racecar, as shown here, fabricators opt for the MIG process using a Bernard Q-Gun and Centerfire nozzle.

 

The addition of Bernard® Q150 air-cooled MIG guns allows Yates’ fabricators to choose between various trigger options—locking trigger, dual pull trigger, dual schedule switch and trigger extension—while the guns’ thick walled rigid strain relief and twist-in direct plugs increase the guns’ durability and make them easier for the crew to maintain. To meet specific weld parameters, whether for skinning the car or MIG welding the floors, Bernard’s Centerfire™ tips, nozzles and diffusers help fabricators maintain consistent arc lengths (because of the fixed nozzle recess), achieve smooth gas flow and reduce spatter—all features essential to creating top quality welds for top quality racecars.

According to Hoffman, “Having such good strain relief on the end of this gun really helps us get the job done—we spend a lot less time changing over components and a lot more time welding. The fact that we are also making consistent, virtually spatter-free welds without much cleanup definitely keeps us on track.”