Here’s How Tesla Glued Together The Cybertruck That Broke During Trailer Hitch Testing

When Tesla started using giant castings to build cars, auto industry commentators rushed to state it would be impossible to economically repair these vehicles. Last year, we ran a big explainer on how these large aluminum parts can actually be fixed after an accident. Now, we’re getting to see what just goes into one of these repairs thanks to YouTuber JerryRigEverything.

The last time we saw JerryRigEverything’s’s Cybertruck, it was in bad shape. A torture testing exercise saw an excavator apply a massive force of 10,400 pounds downwards on the trailer hitch. The rear large component casting — known as megacasting in some rare cases and “gigacasting” in Tesla parlance — of the Cybertruck snapped, and the hitch and rear bumper were effectively torn from the vehicle.

Given that the rear gigacasting is one large continuous part on the Cybertruck, you might think the vehicle would be totaled from this kind of damage. However, as JerryRigEverything’s new video shows us, Tesla has advanced repair techniques to solve just these sort of problems. It sounds silly, but they really can glue everything back together.

Getting Sectioned

The Cybertruck’s chassis is built from three major components—a large aluminum casting in the front, a center section made of high-strength steel, and another large casting at the rear. The castings are made using Tesla’s Gigacasting process, which is so-named because the castings are much larger than was traditionally possible to create with high-pressure die casting techniques.

When JerryRigEverything’s truck was damaged in his torture test on YouTube, the rear casting was snapped off a little ways behind the rear drive unit. The destruction extended to some of the wiring passing through the area.  This effectively immobilized the vehicle, as the Cybertruck’s electronics detected the damage to the wiring harness and shut everything down as a safety precaution.

The original failure is worth the watch.

Upon seeing the rear end torn apart by an excavator, JerryRigEverything had suspected the truck was totaled. Indeed, prevailing opinion in the press over much of the last few years has been that gigacastings are not possible to economically repair. However, as we’ve explored previously at The Autopian, Tesla actually openly publishes repair guides for its gigacastings that lay out precisely how they can be fixed after a crash. You can load them up right in your browser at home.

Investigating the damage, JerryRigEverything notes a particular line on the Cybertruck’s rear casting. If the Cybertruck suffers damage to the rear, it’s possible to section the casting along this line and replace the damaged section. There’s a similar cut line along the middle, too, which indicates where the casting can be cut to replace either the left or right hand side in the event of side impact damage.

A Tesla technician begins repairing JerryRigEverything’s truck by hacking off the damaged rear sections with a reciprocating saw. The cut is made along the designated reference line for replacing a rear section of the casting.

Tesla provides diagrams that indicate where cuts should be made for executing different types of repairs. These diagrams reference obvious features on the casting to guide the technician’s saw. The cuts don’t have to be too exact—there’s a few millimeters of tolerance allowed, since hacking away at broken castings isn’t the most precise science. Once the damaged chunk is removed from the rear of JerryRigEverything’s truck, a handheld sander is used to clean up burrs on the cutline ready for the next step.

Once the cut is made, technicians then line up the replacement rear section with the existing casting. It’s designed to be a snug fit that snaps on to the original casting and holds itself in place. It’s tapped with a hammer to lock it on to the original part. Technicians then apply clamps to hold everything extra securely.

Installing Replacement Pieces Using Rivets And Insanely Strong Glue With ‘Glass Beads’

Holes are then drilled through the original rear casting and the add-on replacement section to make way for rivets. Once drilled, the replacement section is removed and both it and the original casting are cleaned. This is so that the mating parts can be slathered in structural adhesive prior to assembly.

As you might expect, gluing together bits of a vehicle is a serious business. The adhesive chosen for the job is a two-part mix known as Fusor 2098. Produced by Parker, it’s approved for crash repairs by multiple OEMs, including Tesla, GM, Chrysler, and Honda.

It might sound silly to use glue, but this modern adhesive is remarkably strong. It offers a tensile strength of 3,190 pounds per square inch (~22 MPa). It’s not necessarily as strong as the base metal, but applied properly with the right hardware, it can be used to repair the casting to the point where the truck once again meets factory specifications. Taking into account the manner in which it can be applied, it can be a stronger or more practical solution than welding parts back together in some cases.

With Fusor 2098, you get 90 minutes of working time, and parts must then be clamped for six hours during curing. Total cure takes 24 hours. The glue is first applied to the mating parts, then spread out with a brush to create a thick consistent layer. A second layer is then squirted on top to ensure there’s plenty of glue to squish out of the joint when it’s assembled. If you were ever criticized for using too much glue in craft projects as a kid, this is almost the opposite. Tesla’s technicians can be seen laying it on thick when repairing JerryRigEverything’s truck. It’s also notable that the two-part epoxy contains microscopic “non-compressible” glass beads, which ensure that not too much glue is squeezed out when the parts are brought together.

With the glue applied, the replacement sections are assembled on to the original casting, including overlapping plates to bridge across the cutline and add strength. The rivets are then installed, but make no mistake—they’re largely just there to ensure the pieces locate correctly. The glue is what’s really creating the majority of the strength in the joint. For a neater look, the Tesla technicians wipe off excess glue that squeezes out of the joints as they’re assembled and riveted together.

With the rear replacement frame rail sections assembled on the damaged casting, the glue was allowed to set for the standard 24-hour period. Once done, the steel receiver hitch could be bolted back on to the now-repaired rear gigacasting.

JerryRigEverything also notes that the Cybertruck features seperate bolt-on energy absorbers as part of the rear bumper assembly. These aluminum parts are cast with ripples to crumple and absorb energy when hit from behind. For lower-energy crashes, they can take the brunt of an impact and be easily and cheaply swapped out, ideally avoiding damage to the main rear gigacasting. “The parts that are most likely to be damaged are super easy to swap out,” says JerryRigEverything.

With all those components in place, it’s time to reassemble the rest of the panels and support structures that make up the rear of the Cybertruck. Everything is lined up in position, and the tailgate and panels checked for fit before drilling holes and mounting the tailgate support towers to the repaired section of the rear gigacasting. When the fit is correct, the tailgate support towers are covered in the same structural adhesive before they’re riveted up, clamped, and allowed to set in place.

“When I snapped the Cybertruck casting during my tongue weight durability test, I assumed that the whole truck was completely totaled, or that it would cost more than the truck was worth to repair since the casting basically is the whole truck,” says JerryRigEverything. “But thanks to this sectioning procedure, I was pleasantly surprised to learn that my poor decision making didn’t total out the truck.” The final repair cost came in at $13,994, with the repairs taking less than a week at Tesla’s collision center.

“Now obviously, no two accidents are the same,” says JerryRigEverything. “Unless you’re specifically ripping your hitch off with an excavator, your repair costs will probably be different.” Jerry also notes that his torture test wasn’t necessarily representative of real world scenarios of driving and towing with a Cybertruck. “I just want to clarify, while finding the failure limit of the Cybertruck’s tongue weight was extremely fun, it did fail at ten times its static tongue weight load rating,” says JerryRigEverything.

He found the rear casting failed at at tongue weight of approximately 10,400 pounds, while as per Tesla’s specification, the tongue weight is not supposed to exceed 1,100 pounds. “As long as you load and balance your trailer correctly, the Cybertruck will always be able to tow its weighted capacity just fine,” he says.

Lifting The Cybertruck Via A 2.5″ Circle Of Glue

With his truck repaired, JerryRigEverything wraps his video up with one final test. To show off the strength of the Fusor 2098 adhesive, he uses it to glue together two aluminum lifting eyes with a simple butt joint. The glue joint measures just 2.5 inches in diameter. On paper, the joint should be able to withstand 15,000 pounds—the weight of over two Cybertrucks—in tensile loading. After following the proper application and curing guidelines, JerryRigEverything demonstrates the astounding ability of this adhesive by using the the assembled glue joint to lift his Cybertruck from a crane.

It’s an intuitive way to show off just how strong this adhesive really is.  “The strength of the glue is not something to worry about,” he says. “Judging by the amount of adhesive they put on that rear casting, I bet it is just as strong now as it was originally.”

Fixing A Tesla Gigacasting Doesn’t Look As Hard As Some Thought

Coming in with a low-five-figure bill, JerryRigEverything’s repair wasn’t that cheap, but given the nature of the damage, it could have been worse. It was by no means anywhere near expensive enough to risk totaling the vehicle. While it’s never desirable to see your vehicle suffer major structural damage, this video shows quite clearly that it’s not the disaster some have made it out to be. Gigacastings can be repaired, and this is the most direct and visual proof we’ve had yet. Fears around gigacasting repairs have been given a lot of air time, but this video shows truth behind the hype.

Image credits: JerryRigEverything via YouTube screenshot, Tesla