Carbon damage

For discussions about bikes and equipment.
Canuk
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Re: Carbon damage

Postby Canuk » 3 Jan 2019, 11:07am

mig wrote:would you have a carbon fork repaired?


A good quality brand new carbon fork from a reputable Taiwanese manufacturer costs between £40-60.

It wouldn't be be cost effective to do so, when a top quality fork is available after market at this price.

I ask you the same question, would you have an aluminium or titanium fork repaired?

mig
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Joined: 19 Oct 2011, 9:39pm

Re: Carbon damage

Postby mig » 3 Jan 2019, 11:10am

Canuk wrote:
mig wrote:would you have a carbon fork repaired?


A good quality brand new carbon fork from a reputable Taiwanese manufacturer costs between £40-60.

It wouldn't be be cost effective to do so, when a top quality fork is available after market at this price.

I ask you the same question, would you have an aluminium or titanium fork repaired?


no, but then again i wouldn't ride a bike with one.

Canuk
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Joined: 4 Oct 2016, 11:43pm

Re: Carbon damage

Postby Canuk » 3 Jan 2019, 11:17am

mig wrote:
Canuk wrote:
mig wrote:would you have a carbon fork repaired?


A good quality brand new carbon fork from a reputable Taiwanese manufacturer costs between £40-60.

It wouldn't be be cost effective to do so, when a top quality fork is available after market at this price.

I ask you the same question, would you have an aluminium or titanium fork repaired?


no, but then again i wouldn't ride a bike with one.


Would you repair a steel fork, when you could buy a brand new chrome plate Cr-Mo fork for £70? I doubt it. Forks are consumables now. FWIW I've never broken a fork, ever. But I have had the fork crown come partially away from the steerer on a vintage 531 Dawes Galaxy, in the days when they were knocked out ten to the dozen in the UK. The Taiwanese version is a quantum leap ahead of that.

mig
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Joined: 19 Oct 2011, 9:39pm

Re: Carbon damage

Postby mig » 3 Jan 2019, 12:12pm

maybe yes. depends on the damage vs cost of course. i do have a good framebuilder in the LBS though.

the youtube video 'still' for the carbon repair company showed substantial damage to a carbon fork but economics dictate that a new one would be the preferred option anyway? that must reduce their market somewhat. perhaps they just bang in a new one anyway and post it back! :wink:

Vorpal
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Re: Carbon damage

Postby Vorpal » 3 Jan 2019, 12:22pm

If it was mine, I would
a) make an appointment to get it looked at
b) ride it in the meanwhile & keep an eye on it

If it is damaged, it can break suddenly. If it does break, it's likely to do so under high stresses, such as occur when hitting a pothole, accelerating from stop, honking up a steep hill, hard braking, etc.
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― Nelson Mandela, Long Walk to Freedom

apriestley881
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Joined: 30 Dec 2018, 8:48pm

Re: Carbon damage

Postby apriestley881 » 3 Jan 2019, 10:52pm

Hi Guys, still here. Hadn't checked the thread as I had expected to be notified by email when I got replies. I am based in Northern Ireland and had previously contacted Donard Bikes who said they were to busy to fix it. Owen, the owner of Donard Bikes had a quick look at my frame in person and said it was cracked but did not use any X-RAY equipment to look at it. If I do get it X-RAYED and am certain it is a crack, do you think it's safe to get it repaired by a Marine Repair Specialist? I haven't been riding on it but have been keeping a close eye on it. Damage remains unchanged and still no flex from damaged area when pressure is applied.

Vorpal
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Re: Carbon damage

Postby Vorpal » 4 Jan 2019, 8:30am

apriestley881 wrote:Hi Guys, still here. Hadn't checked the thread as I had expected to be notified by email when I got replies. I am based in Northern Ireland and had previously contacted Donard Bikes who said they were to busy to fix it. Owen, the owner of Donard Bikes had a quick look at my frame in person and said it was cracked but did not use any X-RAY equipment to look at it. If I do get it X-RAYED and am certain it is a crack, do you think it's safe to get it repaired by a Marine Repair Specialist? I haven't been riding on it but have been keeping a close eye on it. Damage remains unchanged and still no flex from damaged area when pressure is applied.

I expect that it is safe. They may notunderstand all of the stresses in a bicycle frames, but the materials are not significantly different. There may be a trade-off between appearance and strength. I would err on the side of strength. Discuss it with the repairer.

I t may be worth your time and effort to find another shop that repairs carbon fibre bicycle frames, though. If Donard Bikes are too busy, do they know of the next nearest places that can do it?

Edited to add: if you want to receive email about replies, click on the little spanner at the bottom, and make sure the box is ticked for topic subscription. If it was alread ticked, adn and you havenæt gotten email, check under your user control panel that it shows up under watched threads, and that your email address is correct.
“In some ways, it is easier to be a dissident, for then one is without responsibility.”
― Nelson Mandela, Long Walk to Freedom

alexnharvey
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Re: Carbon damage

Postby alexnharvey » 4 Jan 2019, 10:28am

You haven't said how the damage occurred which would be helpful to know, as would better quality pictures. Although if someone in the bike trade has inspected it in person and told you it's cracked I'd tend to believe them.

As for repair, it really depends on what they mean by describing themselves as a "Marine Repair Specialist". Is this a bog standard boat repairer giving themselves a slightly grandiose title or someone who has additional training and experience to undertake repairs on highly stressed carbon laminates?
You could ask the boat repairer if they've worked on carbon spars, that is the closest job in boat repair to what you're asking them to do. If they don't have lots of experience working on carbon masts and spinnaker poles I wouldn't let them touch your bike. I spent a bit of time working as a subcontractor for a boat repairer working on glass fibre boats and yachts and personally, I wouldn't have tried to fix a customer's carbon mast without training. If they can do good repairs on carbon spars then a bike repair should be manageable and they still might not do as good a job cosmetically as a specialist in carbon bike repairs.

I was impressed with processes shown in the GCN video posted before. If you're going to get it done, get it done right.

As an aside, it would be very good if the forum defaulted to notifying the original posters of topics by email, as the OP expected.

apriestley881
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Joined: 30 Dec 2018, 8:48pm

Re: Carbon damage

Postby apriestley881 » 4 Jan 2019, 4:57pm

The damage happened when the frame had been posted for fitting of a part.
Had the bike scanned and it is definitely cracked (this was done using ultra sound). Will post the photos of the extent of damage later.
As far as im aware the next closest carbon bike repair company is in Dublin, Ireand or England.
The 'marine repair specialist' has "40 years experience working with industrial grp and other composites, Bryan Willis Marine can offer a comprehensive service maintaining GRP, FRP and Carbon Fibre devices and components."

reohn2
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Re: Carbon damage

Postby reohn2 » 4 Jan 2019, 5:33pm

Brucey wrote:......... This sort of damage is (IME) easily caused by something as 'unusual' as the bike falling over.

cheers

It's my concern with CF frames and forks,the damage on the face of it looks small but could be much worse where it can't be seen,whereas a metal frame will dent and although unsightly does not compromise the frame's strength.
Obviously that doesn't apply to all metal frame dents but most are usually nothing but unsightly.
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Airsporter1st
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Re: Carbon damage

Postby Airsporter1st » 4 Jan 2019, 5:37pm

apriestley881 wrote:The damage happened when the frame had been posted for fitting of a part.
Had the bike scanned and it is definitely cracked (this was done using ultra sound). Will post the photos of the extent of damage later.
As far as im aware the next closest carbon bike repair company is in Dublin, Ireand or England.
The 'marine repair specialist' has "40 years experience working with industrial grp and other composites, Bryan Willis Marine can offer a comprehensive service maintaining GRP, FRP and Carbon Fibre devices and components."


Unless they have experience of bike frames and/or the ability to calculate stresses, they may 'play it safe' and make a much thicker/more extensive repair than strictly necessary. The only drawbacks to that, I would think, are a possible loss of flexibility, increased cost and an adverse affect on aesthetics.

landsurfer
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Re: Carbon damage

Postby landsurfer » 4 Jan 2019, 5:46pm

As i have posted on here a few times, in other posts .... my working experience with carbon fibre structures in the Aerospace field is not totally positive ... a knock or minor impact "may" lead to de-lamination of the tubular structure.
The evidence of which is failure of the structure ... no warning .. failure ..
However that failure may be a "soft" failure .... twisting of a frame etc .. or a "sudden" failure ... a tube snapping .. there is no practical way of discerning which it will be ...

I will refer to John ... a regular TT-ist ... from Ards ... who saws up his carbon TT frames and skips them after each 2 full seasons of competition ... "Im not taking the risk, and i'm not selling the risk on" ...
John is a Chartered Mechanical Engineer in the Aerospace sector ...
I'm with John.
Ulster will fight, and Ulster will be right ... Carson.
The Road Goes On Forever ...

mig
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Re: Carbon damage

Postby mig » 4 Jan 2019, 10:08pm

yeah but if someone sent the bits off to the above company......

apriestley881
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Joined: 30 Dec 2018, 8:48pm

Re: Carbon damage

Postby apriestley881 » 5 Jan 2019, 3:53pm

I have tried to attach the images of the ultrasound results but keep getting a HTTP Error. Anyone know how to fix this?

Vorpal
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Re: Carbon damage

Postby Vorpal » 5 Jan 2019, 4:48pm

apriestley881 wrote:I have tried to attach the images of the ultrasound results but keep getting a HTTP Error. Anyone know how to fix this?

It's probably the file format.

Can you convert it to jpg?
“In some ways, it is easier to be a dissident, for then one is without responsibility.”
― Nelson Mandela, Long Walk to Freedom