CyclistBlack Magic: Inside Carbon Bike RepairThis was CBRs first repair, and wow it was broken. It was in about 15 pieces, says Rob Granville, turning over an intriguing-looking Cervlo frame in his hands thats somehow both scarred yet perfectly smooth. The guy lost his arm on this bike. He time-trialled into the front of this car and his arm went into the grille and he got flung over the roof and his arm got left behind. The bike veered off pretty much intact but then got run over by an articulated truck.He actually came in with a different bike but told me about this one and said we could have it to fiddle around with we had nothing to practise on back then. He said, Itll come in a bin bag, and I said, Yeah well get that going again, and we did, even with all the damage and the missing material. Him? Yeah, the doctors managed to sew his arm back on.Granville is the founder of Carbon Bike Repair, which, you guessed it, repairs carbon fibre bicycles. Judging from the queue of frames hanging on the in rack at the entrance to the main workshop, theres little that cant be fixed, from hairline fractures and chain-suck scars through to severed stays and ripped-off head tubes. They come from far and wide, and if you ever wondered how good such a repair could be, you need only examine CBRs list of customers.Along with the private customers, we deal with insurance company claims, brand warranties and referrals we work with brands like Trek and Specialized and pro teams, and youd be amazed at what we can repair, or what people want to get repaired. Like Luke Rowes Pinarello. It was on the roof of a team car that clipped a gazebo and it punctured a hole in the down tube. That bike was brought over during a race, we fixed it over one night, painted it, and sent it back.I remember saying to Team Sky, Why dont you give him a new bike? The bike is screwed. They said its his lucky bike, and often thats what its about. Everyone feels something for their favourite bike, and we can usually help.Article continues belowMike MassaroMike MassaroMike MassaroMike MassaroMike MassaroMike MassaroMike MassaroMethod and rationaleCarbon Bike Repair has been going since 2013. An industrial designer by trade, Granville found himself inspired into road riding by the 2012 Olympics only to find the carbon bikes he desired were expensive. So instead he bought a broken one a Bianchi Oltre for 80 quid, and I used my background and education to figure out how to repair it.That bike got noticed on a ride and led Granville to his first unofficial customer with a broken De Rosa.After that I was inundated. Everyone had a problem, and I thought, No ones sorting these guys out. I was selling my company so I moved over one of my best employees, Marek, and we set ourselves up in my garage and slowly developed our repair process. There was no carbon fibre repair handbook when we started. We wrote it ourselves.Since then CBR has expanded into larger premises in Leatherhead plus another in Granvilles native South Africa. At the UK branch alone proudly displayed as an ever-increasing number on a giant counter in the office theyve dealt with nearly 20,000 bikes.We can pretty much fix anything so long as the frame geometry isnt totally wrecked or its not something like a fork crown or wheel rim bead hook, where we couldnt guarantee the safety on such high-stress areas.Over the years repairs have become more specialised, but the fundamentals remain the same as the early days.To demonstrate, were introduced to Jim Hayward, CBRs principal carbon fibre repair technician, whos busy with an endoscope, moving the camera around a suspected crack on a Pinarello Dogma and watching the image on a big screen. This sort of inspection is the first port of call.This has been sent by Pinarello. Its new but theyre worried it has been damaged in transit so Im trying to determine if this is a hairline crack in the top tube, says Hayward. On this occasion the crack is cosmetic so its off to CBRs paintshop before being returned to Pinarello.This is one side of the business, says Hayward, with CBR offering health checks to frames, verifying their integrity after, say, a crash, using processes such as ultrasound and thermographic imaging. But reaching for another frame, a Specialized Venge, he shows us the other end of the spectrum. The frame was all but severed across the seatstays, seat tube and down tube.This guy was hit by a car he was OK but then the driver drove over the bike. Its an old-generation Venge, so even though the repair will probably be half the cost of a new frame, its for sentimental reasons really.Despite its serious-looking nature, Hayward says the processes for such a repair are relatively straightforward. First, all the broken material is removed from a crack, often ground away with a Dremel. Carbon fibre plies are cut to measure, covered in resin and layered up over the area. The repair is compressed to remove air bubbles and excess resin sometimes with tape, or for larger, more complex repairs, a vacuum bag then cured in an infrared oven. Lastly the repair, which sits proud, is flatted back to match the tube profile before the frame heads to paint.It almost sounds simple, but the reality is anything but. There are special cases that require new tubes to be inserted inside a frame for strength or that require multiple curing cycles due to the intricacy. And thats on top of the years of experience needed to use the tools, plus the expertise in understanding how carbon works. Repairs arent just a case of wrapping a crack in a carbon bandage.You have to repair to the same wall thickness, says Granville. Otherwise you end up with this huge lump of material in a thin tube, and where thick meets thin the stresses are concentrated and the repair can break. So if youve got a hole in a tube, you have to fix the inside bases so that the inside of the tube is represented, otherwise the repair collapses in on itself and you end up with a bulbous lump on the inside of the tube. Thats where the experience and skill of someone like Jim comes in, and the very specific way we grind out the broken area to leave enough material to bond to.On that last point, Granville will say no more the way the edges of a broken area are prepared in a stepped or feathered way (although he doesnt use these words) is crucial to the integrity of a repair and hence a closely guarded secret. Do it wrong and theres either not enough material to bond to or you remove too much, unnecessarily undermining the frame. Its art as much as science, but there are specialist tools CBRs technicians can call on to help, such as an ultrasound scanner to reveal the thickness of a tube wall. Then, more recently, theres Frank.Article continues belowThe journey of a broken carbon frame1: A Specialized Venge snapped through the down tube and stays joins the repair queue.Mike Massaro2 (above and below): Senior technician Jim Hayward ascertains the true extent of the damage using methods such as ultrasound, thermographic imaging and endoscopy.Mike MassaroMike Massaro3: Compromised material is ground away from the repair area in preparation for re-wrapping.Mike Massaro4: Carbon plies are cut and soaked in resinMike Massaro5: then wrapped in layers around the repair area.Mike Massaro6: The new plies are compacted to remove voids and excess resin either with compression tape or vacuum bagging.Mike Massaro7: Repair areas are masked and highlighted to protect existing material.Mike Massaro8: Frames or parts are baked in an infrared oven, which speeds up the curing process over a regular oven, making repairs possible in a day.Mike Massaro9: The cured repair area. Note how the area now sits proud of the tube, which is where Frank comes inMike Massaro10: Frank the robot precisely grinds away the excess repair material to fractions of a millimetre to seamlessly match the tubes original profile.Mike Massaro11 (above and below): Repaired frames are sent to paint. Here, CBRs technical manager, Marek Homola, shows us the huge archive of logos that are necessary, all of which are made in-house.Mike MassaroMike Massaro12 (above and below): The team is constantly learning about, and assessing, its work and others, as CBR founder Rob Granville shows us with a cut-up Cervlo. Knowledge is key, and nothing reaches paint unless it has been perfectly repaired.Mike MassaroMike Massaro13: Jim Hayward appraises a repaired Pinarello Dogma, which at one point had all but lost its head tube, among other serious damage. Youd never know it. Repairs take from one to five weeks, while costs range from hundreds to thousands, depending on complexity.Mike MassaroAutomated serviceSitting in a huge metal box with a Perspex window, Frank is a giant, orange robotic arm with a tiny grinding tip for a finger. On Franks jig is a Bianchi Infinito, whose two substantial breaks through top tube and seat tube are wrapped and cured and ready for the reprofiling that will make them all but invisible.Frank allows us to reprofile those tubes exactly to match the original profiles, to fractions of a millimetre, says Hayward as the robot arm comes to life, making tiny vertical movements up and down the top tube as it grinds the excess material away.Key to this process is 3D scanning. The technicians need to guide Frank He cant exactly see or feel the bike, says Hayward which means inputting a virtual model of the repair area then programming Frank to grind away the precise excess but no more. Its ostensibly the same thing Hayward also does by hand, only with Frank its exceptionally precise, something that has become increasingly necessary given how thin modern tube walls have become. Even so, theres huge potential for error. Hayward reaches up to get a broken frame off the wall.This is a reminder of just how powerful Frank is. You have to program the arm to return home [to its folded position] after the grinding, and on this frame we got the coordinates wrong and Frank just tore through the frame on its way back. Its also why you can never be inside the box when its on. It wouldnt stop if you were in the way.Its impressive stuff, but it does beg a question: with brands consistently banging the drum about how their very specific carbon layup affects how a bike rides, could such repairs ruin ride characteristics, and can they truly last?Maybe you could make that argument, but weve never had a customer tell us their bike rides any differently, says Granville, and we give a lifetime warranty on repairs except for areas we call interfaces, like a seat clamp, which can get crushed by the user. Last year we had a 0.04% return rate.Final phaseAfter the structural side of the repair comes the paint, which is all done in-house.The aim is to give you the bike back, and you say, Oh, wheres the repair? says Marek Homola, CBRs original employee and technical manager. But paint is becoming more challenging. What looks like a small, simple area can mean a whole repaint of a tube, so the final part is making a repair disappear. Paint is where the magic happens.Its a complex business of artistry and invention. Paint needs to be mixed and matched often by eye, and logos, for example, arent readily supplied by brands, so Homola and his painters will work off photographs of bikes, painstakingly rendering them as computer images so they can then be printed and applied. The result is an ever-growing archive, as evidenced by the Colnago crib-sheet Homola brings up on his screen, which contains everything from Colnago logos across the years to the highly intricate, airbrushed Master graphics.At the start I used to do every single bicycle, says Homola, who also, perhaps unsurprisingly, is a luthier, making guitars in his spare time. Now theyre too complicated for just one person. It would be too slow and we have too many to restore.Its certainly a good problem to have, and indeed one full of job satisfaction and not just because of the repairs.Its been a pleasure running CBR and meeting the customers, says Granville. My God, the stories behind the bikes we get turbo trainer heart attacks, being attacked by an illegal fox hunt on a gravel ride. One of my favourites was this guy who got up early one morning and hit the road. He got to a roundabout and there was one car on the road. And that one car, she was on the phone, didnt see him, so she hit him as he was going around the corner, launching him into the air. He had a backpack on and that caught him on the roof-rack how he survived, I mean. But the funny thing was, he was trapped on her roof, the bike was there, but he was gone. She was so freaked out that she called the emergency services and from the roof he can hear her saying, I dont know how to say this, but I think I just hit a ghost. Yeah, we fixed his bike.The post Black Magic: Inside Carbon Bike Repair appeared first on Cyclist.