Small crack on the head tube

[Digga]

Poloding Along said:

Could it be possible to drill a hole at the sharp end of the crack to stop it propagating further and then take it to a machine shop and have a collar put on at the base?

Not sure if this would work, just floating an idea.

No.

1. It won't stop the crack propagating further in the frame.
2. My original opinion - which I stick to - is that the crack may weld be propagating from beneath the weld, not to it. In which case a collar won't stop it opening and spreading further up the headtube or into the down tube.

As I was once told about my first mtb frame; the only thing it's good for is filling a gap in the fence.

[rhinochopig]

Digga said:

No.

1. It won't stop the crack propagating further in the frame.
2. My original opinion - which I stick to - is that the crack may weld be propagating from beneath the weld, not to it. In which case a collar won't stop it opening and spreading further up the headtube or into the down tube.

As I was once told about my first mtb frame; the only thing it's good for is filling a gap in the fence.

The other use is to chop of the bottom bracket along with a few inches of the tubes, mount it on a wooden base, and turn it into a crash of the month trophy.

[Digga]

rhinochopig said:

The other use is to chop of the bottom bracket along with a few inches of the tubes, mount it on a wooden base, and turn it into a crash of the month trophy.

Or as Brant richard 'alledgedgly' (according to a post on another forum) told someone who'd called to complain about the headtube cracking on a 456ti; use it as a coat hanger.

[Gooby]

Digga said:

Poloding Along said:

Could it be possible to drill a hole at the sharp end of the crack to stop it propagating further and then take it to a machine shop and have a collar put on at the base?

Not sure if this would work, just floating an idea.

No.

1. It won't stop the crack propagating further in the frame.
2. My original opinion - which I stick to - is that the crack may weld be propagating from beneath the weld, not to it. In which case a collar won't stop it opening and spreading further up the headtube or into the down tube.

As I was once told about my first mtb frame; the only thing it's good for is filling a gap in the fence.

The only way I could see to repair that would be to TIG weld the fracture up into the the weld it has propogated from. This has only a limited chance of success because
1) Aluminium is VERY difficult to weld in this kind of situation
2) TIG welding causes a lot of heat to build up in the component and has a fait chance of inducing a heat stress deformity
3) the threads within the component will have to be re-cut
4) Frame will need to be re-painted.

All this means it is probably cheaper to replace the frame.

I am not being judgemental here but it doesnt look to be a very expensive frame, I am basing that assumption on the bearing shown in the picture, quality kit isnt stamped, and it isnt stamped "made in Italy".

I have a fair amount of experience with industrial adhesives and the thought of using "plastic metal" to repair this fills me with dredd that you may actually try it! Plastic metal will not withstand the vibration and subben shock that this part of the frame has to withstand. Put it this way, would you bet a long stay in hospital that it would work?

[BliarOut]

Gooby said:

Digga said:

Poloding Along said:

Could it be possible to drill a hole at the sharp end of the crack to stop it propagating further and then take it to a machine shop and have a collar put on at the base?

Not sure if this would work, just floating an idea.

No.

1. It won't stop the crack propagating further in the frame.
2. My original opinion - which I stick to - is that the crack may weld be propagating from beneath the weld, not to it. In which case a collar won't stop it opening and spreading further up the headtube or into the down tube.

As I was once told about my first mtb frame; the only thing it's good for is filling a gap in the fence.

The only way I could see to repair that would be to TIG weld the fracture up into the the weld it has propogated from. This has only a limited chance of success because
1) Aluminium is VERY difficult to weld in this kind of situation
2) TIG welding causes a lot of heat to build up in the component and has a fait chance of inducing a heat stress deformity
3) the threads within the component will have to be re-cut
4) Frame will need to be re-painted.

All this means it is probably cheaper to replace the frame.

I am not being judgemental here but it doesnt look to be a very expensive frame, I am basing that assumption on the bearing shown in the picture, quality kit isnt stamped, and it isnt stamped "made in Italy".

I have a fair amount of experience with industrial adhesives and the thought of using "plastic metal" to repair this fills me with dredd that you may actually try it! Plastic metal will not withstand the vibration and subben shock that this part of the frame has to withstand. Put it this way, would you bet a long stay in hospital that it would work?

Pah, I've drilled it, tapped it, filed it, blued it till it makes an oil tight crankcase seal. Any idea how much a Ducati engine, or coming to that former nose in the folder of a newspaper press vibrates? Used properly it's amazing stuff.

[ShredderXLE]

Gooby said:

I am not being judgemental here but it doesnt look to be a very expensive frame, I am basing that assumption on the bearing shown in the picture, quality kit isnt stamped, and it isnt stamped "made in Italy".

That stamp is on the headset cup (probably campagnolo) and is a completely separate component from the frame.....which being a Pinarello I would imagine would be made in Italy too (although the "surprise" was their basic frame in the range it is still very nice)

[Gooby]

ShredderXLE said:

Gooby said:

I am not being judgemental here but it doesnt look to be a very expensive frame, I am basing that assumption on the bearing shown in the picture, quality kit isnt stamped, and it isnt stamped "made in Italy".

That stamp is on the headset cup (probably campagnolo) and is a completely separate component from the frame.....which being a Pinarello I would imagine would be made in Italy too (although the "surprise" was their basic frame in the range it is still very nice)

I am not disputing that - there is no such thing as nasty Pinarello but ...
ok, my comment was dismissive and I am sorry...

[Gooby]

BliarOut said:

Pah, I've drilled it, tapped it, filed it, blued it till it makes an oil tight crankcase seal. Any idea how much a Ducati engine, or coming to that former nose in the folder of a newspaper press vibrates? Used properly it's amazing stuff.

I will agree - the right adhesive in the right place can be incredible. I ran a project where we were putting £150k optic on the nose of a £100k airbearing with an industrial superglue then spinning it at 80,000 rpm. Before we perfected the gluing procedure, I have seen a failure and the optic disapear through a bullet proof test casing, through a wooden lab desk and leave through a wall....

It isnt the vibration that is the problem, it is the sudden shock from hitting a pothole etc that will cause the failure. Having seen some of the finite element analysis conducted for Cerevelo, the point stress that this component is under is huge and I wouldnt trust that to plastic metal.

[Roman]

Gooby said:

BliarOut said:

Pah, I've drilled it, tapped it, filed it, blued it till it makes an oil tight crankcase seal. Any idea how much a Ducati engine, or coming to that former nose in the folder of a newspaper press vibrates? Used properly it's amazing stuff.

I will agree - the right adhesive in the right place can be incredible. I ran a project where we were putting £150k optic on the nose of a £100k airbearing with an industrial superglue then spinning it at 80,000 rpm. Before we perfected the gluing procedure, I have seen a failure and the optic disapear through a bullet proof test casing, through a wooden lab desk and leave through a wall....

It isnt the vibration that is the problem, it is the sudden shock from hitting a pothole etc that will cause the failure. Having seen some of the finite element analysis conducted for Cerevelo, the point stress that this component is under is huge and I wouldnt trust that to plastic metal.

As great as Plastic Metal sounds I wouldn't bet my safety on a crack that's been filled with it having greater tensile strength than the original non faulty/damaged component (and even that failed).

Every time you hit a pothole or brake there will be forces trying to pull the crack further apart and if it does fail it could be sudden and under high load/speed.

To me the base model Pinarello ali frames look just like generic Taiwanese ali frames produced for the likes of Kinesis, Raleigh etc and available to buy for around £150-£200 - nothing wrong with that if they are.

[BliarOut]

Roman said:

Gooby said:

BliarOut said:

Pah, I've drilled it, tapped it, filed it, blued it till it makes an oil tight crankcase seal. Any idea how much a Ducati engine, or coming to that former nose in the folder of a newspaper press vibrates? Used properly it's amazing stuff.

I will agree - the right adhesive in the right place can be incredible. I ran a project where we were putting £150k optic on the nose of a £100k airbearing with an industrial superglue then spinning it at 80,000 rpm. Before we perfected the gluing procedure, I have seen a failure and the optic disapear through a bullet proof test casing, through a wooden lab desk and leave through a wall....

It isnt the vibration that is the problem, it is the sudden shock from hitting a pothole etc that will cause the failure. Having seen some of the finite element analysis conducted for Cerevelo, the point stress that this component is under is huge and I wouldnt trust that to plastic metal.

As great as Plastic Metal sounds I wouldn't bet my safety on it having greater tensile strength than the original non faulty/damaged component (and even that failed).

Every time you hit a pothole or brake there will be forces trying to pull the crack further apart and if it does fail it could be sudden and under high load/speed.

To me the base model Pinarello ali frames look just like generic Taiwanese ali frames produced for the likes of Kinesis, Raleigh etc and available to buy for around £150-£200 - nothing wrong with that if they are.

Do you ever fly?

[Roman]

BliarOut said:

Roman said:

Gooby said:

BliarOut said:

Pah, I've drilled it, tapped it, filed it, blued it till it makes an oil tight crankcase seal. Any idea how much a Ducati engine, or coming to that former nose in the folder of a newspaper press vibrates? Used properly it's amazing stuff.

I will agree - the right adhesive in the right place can be incredible. I ran a project where we were putting £150k optic on the nose of a £100k airbearing with an industrial superglue then spinning it at 80,000 rpm. Before we perfected the gluing procedure, I have seen a failure and the optic disapear through a bullet proof test casing, through a wooden lab desk and leave through a wall....

It isnt the vibration that is the problem, it is the sudden shock from hitting a pothole etc that will cause the failure. Having seen some of the finite element analysis conducted for Cerevelo, the point stress that this component is under is huge and I wouldnt trust that to plastic metal.

As great as Plastic Metal sounds I wouldn't bet my safety on it having greater tensile strength than the original non faulty/damaged component (and even that failed).

Every time you hit a pothole or brake there will be forces trying to pull the crack further apart and if it does fail it could be sudden and under high load/speed.

To me the base model Pinarello ali frames look just like generic Taiwanese ali frames produced for the likes of Kinesis, Raleigh etc and available to buy for around £150-£200 - nothing wrong with that if they are.

Do you ever fly?

Yes, why?

Do they repair already failing components under high tensile loads with Plastic Metal as opposed to replacing them?

[BliarOut]

There's a teeny side load when you corner as the bearing cup spreads the load, the majority of the forces are in compression and are again spread.

I'd be quite happy to ride it


Planes, wings, glue... Scary st

[Roman]

No those forces wouldn't bother me - it would be the force of 100kg of rider and bike at 40mph hitting a pothole or emergency braking trying to rip the crack further apart that would make me feel less comfortable!

For all we can tell it could be fractured half way up the headtube.

I'm not against ali & glue by any means though - I used to race on a duralinum frame with bonded joints and loved it. However, once the rear mech hanger and seat collar snapped I never felt confident in it during bunch sprints following repairs so it was replaced and passed on to my Father for an easier life riding too and from his Cricket club!

[Digga]

Gooby said:

BliarOut said:

Pah, I've drilled it, tapped it, filed it, blued it till it makes an oil tight crankcase seal. Any idea how much a Ducati engine, or coming to that former nose in the folder of a newspaper press vibrates? Used properly it's amazing stuff.

I will agree - the right adhesive in the right place can be incredible.

And let's face it, any true engineer loves a good, effective bodge.

But there's still no fking way I'd ever ride it. Voodo stuff that 'special glue'.

[BliarOut]

Gimme some Gaffa tape and I'll take the bugger down Ditchling

[Raven Flyer]

You could open the crack out with a Dremel, fill it full of Grip Fill and put a couple of big jubilee clips around it.

Otherwise, the frame is a write off.