In a perfect world, our cars would be built of the same material as Wile E Coyote. Tragic accident involving unlikely ACME boulder-flinging apparatus? No problem, everything will just snap back to normal for the next episode.
Unfortunately, modern cars are made of steel, aluminium, and plastic, and they’re made to crumple on impact to protect their occupants. Modern automotive engineers know that people are much harder to fix than cars, so they build cushioning into their designs. Sadly, that’s turned the once-harmless fender-bender into a full-scale repair.
But that’s what insurance is for, right? You get your claim, and you drop off the keys at your local friendly body shop and then – hey, presto! – your car emerges, good as new after a few days. What, do they have a few ACME-sized general purpose mallets back there? A giant air-compressor to pop that deflated form back into shape again?
With the aftereffects of slippery wintertime conditions in full effect, I walked through the “Employees Only” door at the family-run Coache Collision in North Vancouver, BC. If you’ve just rubbed an unseen post or had a badly-driven Kia bounce off your rear bumper, here’s how a body shop can stitch your ride back together.
A Body of Work
Norbert Tietze’s collision repair shop has been putting the (sometimes careless) denizens of North Vancouver back on the road for nearly four decades now. His father founded the business in the 1970s, mostly specializing in imports. Tietze started off working in the paint booth, and his brother Eric is also an experienced painter in the shop. Tietze’s oldest son is just joining the front office crew, marking three generations in the family business.
In the early going, lead was often used as a filler, the paint was solvent-based, and dent-repair was somewhat easier with thick-gauge steel to work with. These days, the toughest job faced by the team at Coache is probably the never-ending slew of paperwork associated with insurance. Even as a fully-certified shop, documenting every step is key. With approximately thirty cars coming through for repair work every week, the front office is very busy.
It’s in the back, though, that the really interesting stuff happens. Once the claim is filed and the keys handed over, the injured vehicle is brought in to be fully cleaned. There are three basic elements to the repair: the bodywork, the paintwork, and the detailing. Here at Coache, there are six technicians divided between paint and body, and a pair of experienced detailers. These last will be the first to lay hands on a damaged vehicle.
Dissecting the Damage
While he’s an experienced estimator, Tietze knows that there’s more to a potential repair than meets the eye. Surface damage is almost always less than the structural injuries that hide behind panels or under the hood.
First though, any car is fully cleaned and inspected for cosmetic issues. As Norbert says, “Nobody really looks at their car until it’s been in an accident.” Especially in the winter months, when grime and dirt disguise minor cosmetic blemishes, the detailers and technicians are careful to record each flaw in the paint, marking it out with a grease pencil, and making a digital video of the car’s condition as it comes in. Coache has a reputation as a particularly careful and perfection-obsessed shop, and documents everything to ensure that reputation is earned.
Next, the body technicians remove the damaged skin and look for any hidden damage. At this point, the estimate may need to be altered, if something particularly critical is found. Among the cars undergoing work is a stricken grey Kia with its bumper cover off. While the damage looks fairly superficial, the angle of the accident has caused what Norbert refers to as a “sway,” or a shift in the car’s unibody chassis. Head-on, and some of the subframe might have required cutting out and replacement.
Framed Up and Weld Done
The frame straightening is accomplished through the use of hydraulic towers that can be positioned to pull from any direction. Factory alignment tolerances are +/- 5mm, but Coache will repair to within 3mm, using specialized clamps that attach close to the car’s jack points.
Metalwork is done based on a gradient ranging from simple dent repair to factory-style resistance welding. The former involves sanding down to bare metal and then tacking on a small spur to be used to re-work the metal back to its original form. Most dents will come out this way, unless the crease is particularly bad.
Welding is done when there’s a tear in the metal, or if a new skin needs to be put on a door or similar. There are several types of welders in operation in the shop, the largest and most complicated of which is the resistance welder. This huge machine has a business end that looks like the claw of some huge robotic crab; it’s exactly the same tool you might find on a modern automotive factory floor and clamps on to tack the sheetmetal together. A digital readout indicates if the weld is within factory tolerances.
While Coache doesn’t handle structural aluminium, their technicians can replace aluminium body panels. This requires an entirely separate set of tools, as the metals can react with each other to accelerate corrosion.
Finally, filler is also used, very sparingly, mostly as part of the sanding and finishing process before going to paint. Where once unscrupulous shops would fill entire holes with Bondo, the surfacing materials used here are just that, millimetre-thick coats that are mostly sanded off as the body shop crew hand-finishes and primes each job.
Paint by Numbers
“The biggest misconception,” Tietze says, leading the way into the paint booth, “Is that the colour is just the colour. You could take two identical silver cars and park them next to each other and they could be built on different days and be completely different.” Not only is every batch of paint mixed specifically for a car, it doesn’t come from the manufacturers.
In the paintroom, rows of base colours can be measured out onto a scale that gives the paint technician a general formula based on the manufacturer’s paint code. The tech will then use a spray card to test the paint’s actual colour. A light designed to throw off the same wavelength is used to illuminate both card and vehicle paint, and the painter’s experienced eye tweaks the tone until it’s just-right. While computerized systems exist, the skill of a trained tradesman is still more accurate.
Once the car is taped-off, primed and sanded, the base coat of colour is applied. Again, skill is key here, as a certain amount of blending and fading needs to be accomplished so the newly-painted panel doesn’t stand out. Most paint is applied in two stages, a base colour and a clear coat. The specialized paint booth is designed to provide a heated, dry environment to speed the drying process. For most repairs, it will take 90 minutes from a prepped surface to the completed repair.
Some time ago, automotive paint moved from solvent-based to water-based, slowing drying times, but causing less environmental damage. Coache adopted the process early-on, and is continually tweaking its equipment. One innovation can be found in the nitrogen dried and heated air-supply for the pressurized paint gun. With less introduced moisture than a standard paint delivery system, it cuts down on drying time.
Pearl paints are currently the most difficult to repair, with four separate layers, but there is something worse: matte paint. Even in a sealed paint room, dust and contaminants can cause slight irregularities in the paint. With ordinary clearcoat, wet-sanding or polishing can effect a spot repair. With matte-paint, there’s nothing that can be done; it’s a pain to repair and Tietze’s shop would rather not touch it.
Home and Dry
Once the paint is dry, it will technically take six to eight weeks to fully cure. However, any car leaving Coache’s shop is perfectly capable of standing up to a hand-wash – no waxing or polishing of course.
The detailers will have one more careful look over the car before it leaves, and they themselves have a particular skill set when it comes to mastery of the high-speed polisher, and clever tricks to deal with scratches and swirls in paint.
In fact, if there’s a take-away lesson from this busy body shop, it’s that little here, aside from the paperwork, is digitized and computerized. The bodywork technicians should more properly be called craftsmen. The paintwork team should be more properly called artists.
If you’re lucky, you might never need the services provided here. But if your luck runs out, well, just be glad they’re so good at what they do.