Will you repair this?

[leeubok]

And, (I think this is really important), we keep an environmentally dirty bike on the road instead of landfill. Carbon fibre is very dirty to produce. It's mostly made from pitch, dirty, oily tar, at huge energy costs. The epoxy resin is full of carcinogens and nasty chemicals... Processing the carbon takes a 700kPa pressurised 120 degree oven!

 

It's much greener to keep it on the road and not waste all of that effort than to scrap it and make another bike from scratch.

Wow, I didn't know this! 

 

I want to echo what others have said, thanks to you and Bogus for the expert advice given here. Graeme, it's a pity I didn't get to meet you in person when I dropped my Pyga frame off at your workshop. I hope there isn't a next time, but maybe I'll just pop in to say hello whenever I'm in Durbs again

Edited November 27, 2019 by leeubok

[ABrooks]

I have a question regarding the inspection of a cracked carbon bike, do you only inspect the crash area or do you inspect the whole bike? Also what method do you use to pick up on cracks in the frame after a crash?

[Mopkop]

I have a question regarding the inspection of a cracked carbon bike, do you only inspect the crash area or do you inspect the whole bike? Also what method do you use to pick up on cracks in the frame after a crash?

 

My Question exactly, still waiting for an answer

[Danger Dassie]

My Question exactly, still waiting for an answer

 

Relax, the okes have thus far been answering everything so far. Sure they'll get to answering the question, no doubt they also have work to do. 

 

Generally laser scanning/xrays can be done, but there are a number of NDT (None Destructive Test) methodologies in use to determine a repair and/or further tests are needed. 

It's also dependant on the inherent design, ie a tight radius on a specific area may need extra tests to be sure there are no voids. 

 

Graeme or Anton will probably give a more detailed idea, but they've already alluded to this in how they asses any possible repair job in the first place.

[NotSoBigBen]

Sometimes it's like being stuck in a badly run bike shop with a load of angry middle aged men around here

 

Entertaining if nothing else [emoji12]

[Mamil]

Thanks Carbon Ninja --

 

I'm sure it's an emotional thing - having seen a bike looking like the one the OP is discussing, I would really battle to feel comfortable trusting the mass of my mamilian bulk to a structure that I knew had been so seriously mangled.

 

And an insurance company that wanted to persuade me to do so would have a tough task.

 

Your explanation goes some way to shedding light on what the process involves so thanks for that.

 

 

 

 

 

I can well understand how you might be incredulous, and I am glad that you acknowledge that you are a layman. This is where trust in the expertise that I have (and you don't) is required.

Fortunately no one forces you to ride a repaired frame, if you can't get your head around it then you must simply opt for another solution.

As for the science, there's plenty but I'll make an attempt to summarise :

CFRP or carbon fibre reinforced plastic comes essentially in two versions, thermoplastic and thermoset. Bikes are made with thermoset resin and this is imminently repairable because it is imminently bondable.

New frames are made in multiple pieces that are glued together, typically stays are glued via lugs to the one piece front triangle. The join is then "taped" to make it one piece. In a job like the one that is the subject of this thread, I would emulate this process by creating an internal lug that joins the two halves of the head tube together, then I would tape the two halves. (Taping is just a term for wrapping carbon fabric on a closed surface, it's not taping like sellotape)!

I have a big that maintains alignment and the lug that I make is largely geometrically conformal with the internal surfaces of the original head tube. In this way a repair adds only 10s of grams to the original mass, rather than hundreds.

Appropriatly selected reinforcing carbon fabric and epoxy matrix then merge the two halves of the head tube via an appropriate consolidation and fibre volume fraction maintaining process. I use VI mostly, sometimes vacuum bagging. You won't find insulation tape in this workshop, no "Pap en Lap" as my colleague Anton calls it!

My methods are all derived from repair method standard best practice from the civilian aerospace industry. These manuals are published by Boeing, Airbus and so on for technicians to make repairs to their planes which are increasingly composite intensive.

Oh, and lastly, I've had the quality of my laminates tested independently. I did this to ensure a low void and high fibre volume fraction laminate a was being repeatably achieved by my repair methodology.

Lastly, I forgot to add, the analogy with orthopedic science is not totally valid, medicine is not an exact science where composites are, pretty much. There are many variables and unknown unknowns in the world of medicine, but luckily in this arena, its far more exacting.

[BogusOne]

My Question exactly, still waiting for an answer

Mainly by visual inspection and sound checks to determine the difference in pitch in areas of concern and generally over the complete frame if it was involved in a crash or incident.

 

In the near future i will be able to actually look at the tubes on the inside as far as possible. Which will make assessments easier as to the extent of internal damages once my endoscope arrives.

 

Unfortunately i do not have access to Xray equipment... Yet...

[CARANXCycleMobile]

Good news your'e ok,as for the bike its chapter 3....Bin it.

Cant believe they want to repair,it will definitely influence the stiffness and ride quality with an/any repair.

[Wayne Potgieter]

OP : “Will you repair this?”

 

Industry professional with oodles of experience and qualifications : “Yes”

 

Bunch of people with no experience or qualifications armed only with opinion: “No! We know better and the professional is wrong!!!”

 

This place makes me laugh.

[shaper]

OP : “Will you repair this?”

Industry professional with oodles of experience and qualifications : “Yes”

Bunch of people with no experience or qualifications armed only with opinion: “No! We know better and the professional is wrong!!!”

This place makes me laugh.

Industry people with no regulation or standards and based on trust of the individual doing the work

[Wayne Potgieter]

Industry people with no regulation or standards and based on trust of the individual doing the work

like most businesses are based on an element of trust.

 

Even if there was a regulatory body, you would simply be transferring your trust to them and their qualifications. The legal ramifications for the contractor are still very real so in some respects having a regulatory body can be a moot point.

[Mudsimus]

OP : “Will you repair this?”

 

Industry professional with oodles of experience and qualifications : “Yes”

 

Bunch of people with no experience or qualifications armed only with opinion: “No! We know better and the professional is wrong!!!”

 

This place makes me laugh.

There is a difference between can this be repaired and will you repair this. We determined that this can be repaired. Through numerous “laughable” opinions its also obvious that almost no one will repair this and would rather replace the frame. Edited November 27, 2019 by Mudsimus

[BigDL]

OP : “Will you repair this?”

 

Industry professional with oodles of experience and qualifications : “Yes”

 

Bunch of people with no experience or qualifications armed only with opinion: “No! We know better and the professional is wrong!!!”

 

This place makes me laugh.

Well said

[Mamil]

There is that aspect to it for sure. And there's also "hand in completely bust up bike. Pick it up in a fortnight and do 75kmph down the hill on it with failure meaning possible death and definite serious injury knowing what it looked like before". And for me that's the basis of the "no way" I've expressed.

 

OP : “Will you repair this?”

 

Industry professional with oodles of experience and qualifications : “Yes”

 

Bunch of people with no experience or qualifications armed only with opinion: “No! We know better and the professional is wrong!!!”

 

This place makes me laugh.

[Wayne Potgieter]

There is that aspect to it for sure. And there's also "hand in completely bust up bike. Pick it up in a fortnight and do 75kmph down the hill on it with failure meaning possible death and definite serious injury knowing what it looked like before". And for me that's the basis of the "no way" I've expressed.

 

 

respectfully speaking this is an opinion.

 

The professional has stipulated and others have confirmed that the repair is stronger than the original (which has already failed)

 

I agree it is nerve wracking but there is an element of danger in this sport.

 

Plus, insurer has the right to repair so the only choice that you have is to accept the repair or deviate from the signed and agreed policy by doing your own thing.

 

(On mobile app please excuse grammar)

[shaper]

like most businesses are based on an element of trust.

Even if there was a regulatory body, you would simply be transferring your trust to them and their qualifications. The legal ramifications for the contractor are still very real so in some respects having a regulatory body can be a moot point.

Most businesses where there is a public liability are regulated and require adequate insurance in place whether proffesional indemnity or contractors all risk, so the level of trust is mitigated and therefore not a moot point.

 

Further in this day and age, most businesses have to maintain a standard by doing a certain numbef of CPD to stay current with regulations, else be at risk of loosing regulatory body status.

 

As stated by both "professionals" there is no regulatory body, just hands on experience and no liability insurance... which is concerning when the insurance industry is pushing for repair rather than replace

Edited November 27, 2019 by shaper