Testing a carbon bike frame- NDT
drplumbster
Posts: 83
Ok.... this is a BIG POST on here!
For a long time, I have searched and explored this issue that seems to crop up time and time again,
How do I know if my crashed carbon frame is safe to ride?
What method is best to check it etc etc etc.....
I have FINALLY found out the answers.....
I have found a very experienced pro who has over 30 years of experience in the NDT industry mostly working with high end yachts, but has a history working with carbon and actually built a carbon bike frame 30 years ago!
I can put people in touch if they want. He is based in the South of England. He is not me, I am getting nothing for this, I was just so pleased to have finally found someone who I trust to do this.
For a long time, I have searched and explored this issue that seems to crop up time and time again,
How do I know if my crashed carbon frame is safe to ride?
What method is best to check it etc etc etc.....
I have FINALLY found out the answers.....
I have found a very experienced pro who has over 30 years of experience in the NDT industry mostly working with high end yachts, but has a history working with carbon and actually built a carbon bike frame 30 years ago!
I can put people in touch if they want. He is based in the South of England. He is not me, I am getting nothing for this, I was just so pleased to have finally found someone who I trust to do this.
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Comments
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I have 25 years expierience in NDT and IMO there is no reliable testing of carbon fiber composites possible.0
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I have 25 years expierience in NDT and IMO there is no reliable testing of carbon fiber composites possible.
Well, this guy thinks that using a combination of techniques it is reliable.
Thermography – Infrared Testing - IR, Liquid Penetrant -PT, Volumetric Examination Method, Ultrasonic Testing -UT.
I am not an NDT expert and you clearly are but the methods used satisfied me.............0 -
So, does the expert think that his 30 year old carbon fibre bike is safe to ride?
If he doesn't know, I'd ask another expert.0 -
I can't remember what the going rate per hour for an NDT inspector was at the company I used to work for but I wouldn't be surprised if the bill exceeded the original cost of the frame several times over after using all those techniques on it.0
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I can't remember what the going rate per hour for an NDT inspector was at the company I used to work for but I wouldn't be surprised if the bill exceeded the original cost of the frame several times over after using all those techniques on it.
This!
I'm not sure the OP will be back but if they do return, how much do they charge?www.conjunctivitis.com - a site for sore eyes0 -
If his expertise is in yachting composites, I'd think he'd be looking for gross delaminations in the hull structures. Whether CF bike frames fail in the same mode is debatable. Dye pen will show cracks - and happily show you cracks in the paint / gel coat that have nothing to do with the structural integrity - ok for steel/alu/Ti, not much cop for composites. UT will show sub-surface voids, which may or may not make the frame unusable, or may have been there since day 1. Never used thermography so can't comment. Volumetric just means UT or RT, it's not a separate technique. And I cannot see how thermographic examination can help on a cold body such as a frame?
So nothing there would necessarily satisfy me. UT or RT would seem to be the most likely (after Mk. 1 eyeball) methods to show defects, but RT (radiographic, or X-ray) is bloody expensive, and UT open to interpretation (quite literally). You HAVE to know what you're looking at to make sense of the results.
All in all I'm very sceptical.0 -
I have 25 years expierience in NDT and IMO there is no reliable testing of carbon fiber composites possible.
Well, this guy thinks that using a combination of techniques it is reliable.
Thermography – Infrared Testing - IR, Liquid Penetrant -PT, Volumetric Examination Method, Ultrasonic Testing -UT.
I am not an NDT expert and you clearly are but the methods used satisfied me.............
If you had to be chraged for all of that, it would probably be cheaper to buy a new frame, no?left the forum March 20230 -
If his expertise is in yachting composites, I'd think he'd be looking for gross delaminations in the hull structures. Whether CF bike frames fail in the same mode is debatable. Dye pen will show cracks - and happily show you cracks in the paint / gel coat that have nothing to do with the structural integrity - ok for steel/alu/Ti, not much cop for composites. UT will show sub-surface voids, which may or may not make the frame unusable, or may have been there since day 1. Never used thermography so can't comment. Volumetric just means UT or RT, it's not a separate technique. And I cannot see how thermographic examination can help on a cold body such as a frame?
So nothing there would necessarily satisfy me. UT or RT would seem to be the most likely (after Mk. 1 eyeball) methods to show defects, but RT (radiographic, or X-ray) is bloody expensive, and UT open to interpretation (quite literally). You HAVE to know what you're looking at to make sense of the results.
All in all I'm very sceptical.
All very true sir.
I would be surpriced if the outcome of all 4 possible metodths together would be more reliable than throwing a dice.0 -
There are various carbon frame repair concerns in the UK that can be Googled, including the one linked below.
http://www.carbonbikerepair.co.uk/?gclid=CjwKEAjwueytBRCmpOyZ2L-xrG8SJADwH5c64SesdjSGEuEafjomjxEqrVLJITi-J0YyjxI60tDHUBoC5Hrw_wcB
They should be able to diagnose non-visible fractures before repair, so should come up with an estimate for you before you have to decide if it's worth having the work done.To err is human, but to make a real balls up takes a super computer.0 -
They should be able, but they're not.0
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I can't remember what the going rate per hour for an NDT inspector was at the company I used to work for but I wouldn't be surprised if the bill exceeded the original cost of the frame several times over after using all those techniques on it.
This!
I'm not sure the OP will be back but if they do return, how much do they charge?
? Why wouldn't I be back? Bit of an odd statement?
The guy (graham) charged me £95 pretty reasonable I would say.0 -
They should be able, but they're not.
If they couldn't diagnose damage then they wouldn't be in the frame repair business. The cost of litigation if a frame failed under a rider after repair would close a business.
Go to a professional frame repair company, rather than someone who is in an associated business.To err is human, but to make a real balls up takes a super computer.0 -
So, they must be good or they wouldn't be doing it? Does this apply to other professions? How about car mechanics, or builders? No one ever has any issues there.They should be able, but they're not.
If they couldn't diagnose damage then they wouldn't be in the frame repair business. The cost of litigation if a frame failed under a rider after repair would close a business.
Pseudo-intellectual, you aren't.0 -
So, they must be good or they wouldn't be doing it? Does this apply to other professions? How about car mechanics, or builders? No one ever has any issues there.They should be able, but they're not.
If they couldn't diagnose damage then they wouldn't be in the frame repair business. The cost of litigation if a frame failed under a rider after repair would close a business.
Pseudo-intellectual, you aren't.
I concede, you have a good point. Let's say being able to diagnose damage should be part of their basic skill set to be in that business.To err is human, but to make a real balls up takes a super computer.0 -
Nice answer. My hunch is that competent use of a suite of analytical techniques would give a pretty good indication of whether or not there was damage, but I honestly don't know.
So, they must be good or they wouldn't be doing it? Does this apply to other professions? How about car mechanics, or builders? No one ever has any issues there.They should be able, but they're not.
If they couldn't diagnose damage then they wouldn't be in the frame repair business. The cost of litigation if a frame failed under a rider after repair would close a business.
Pseudo-intellectual, you aren't.
I concede, you have a good point. Let's say being able to diagnose damage should be part of their basic skill set to be in that business.0 -
As part of my original research I contacted a number of frame repair companies. Not a single one offered anywhere near the level of NDT that I ended up with and most simply offered visual inspection and internal (fibre optic scope) along with 'tap testing' which frankly doesn't tell you anything at all!0
