Author Topic: Tandem frame fracture? (Read 5855 times)

321up · « **on:** 04 August, 2014, 05:21:55 pm »

This looks to me very much like a fatigue fracture...

... your opinions comments please.

LittleWheelsandBig · « **Reply #1 on:** 04 August, 2014, 07:08:52 pm »

What does it look like with the bolt and nut removed?

PAC · « **Reply #2 on:** 04 August, 2014, 08:22:26 pm »

Possibly just the paint that's cracked...? Hopefully...

321up · « **Reply #3 on:** 04 August, 2014, 09:56:05 pm »

Quote from: PAC on 04 August, 2014, 08:22:26 pm

Possibly just the paint that's cracked...? Hopefully...

The suppliers explaination is that the crack in the paint is caused by clamping the wheel in, its reassuring to have a second opinion though. Thanks for the replies.

321up · « **Reply #4 on:** 06 August, 2014, 09:21:33 am »

UPDATE:

Photos with more detail...

Yesterday our supplier upheld their reputation for excellent service and offered to provide us with a frame to use whilst ours is sent back for inspection. We are very grateful as the alternative was to risk using it or cancel our plans for the next two weeks.

321up · « **Reply #5 on:** 06 August, 2014, 09:30:07 am »

I think the design of the dropout could be significantly improved by extending the raised area that the axle lock nut rests against to maximise the thickness of the metal where it is cutout for the hanger on the other side. Having both sides reducing in thickness at the same point is not ideal.

mrcharly-YHT · « **Reply #6 on:** 06 August, 2014, 10:31:17 am »

Classic aluminium fatigue fracture. 'tis the nature of the material, unfortunately. Good to hear the supplier are being cooperative.

Veloman · « **Reply #7 on:** 06 August, 2014, 10:47:59 am »

Glad to hear the supplier is serving you well and I wish you luck with a replacement.

Clearly due to your awesome pedalling technique and mileage!

321up · « **Reply #8 on:** 14 April, 2015, 02:24:20 pm »

Quote from: 321up on 06 August, 2014, 09:21:33 am

UPDATE:

Photos with more detail...

Yesterday our supplier upheld their reputation for excellent service and offered to provide us with a frame to use whilst ours is sent back for inspection. We are very grateful as the alternative was to risk using it or cancel our plans for the next two weeks.

UPDATE: Our supplier replaced our first frame free of charge last year. These are photos of the replacement frame after less than a year and less than 5000 miles of use...

Our supplier says that it's just the paint that cracked. Also they are now saying that the first frame was not fractured, and that they have never had one of these frames crack.

... why would the paint crack like this if the metal is not fractured? Do you think that these frames are fractured? Do you know of any Aluminium Orbit frames that have fractured?

mzjo · « **Reply #9 on:** 14 April, 2015, 03:17:08 pm »

Go to your local welding supplier and get a set of crack testing aerosols. Interpreting the results sometimes needs a bit of experience but it will give you an idea with relatively little expense. Pity we didn't think of that with the first frame, you might have had evidence to present/dispute/discuss.
Normally there are three aerosols, cleaner, penetrant and developer but often over here users don't seem to bother about buying the cleaner.

Biggsy · « **Reply #10 on:** 14 April, 2015, 03:28:58 pm »

In the first two first Update photos, there are lines in the bare metal in line with the cracks in the paint. There are two of these coincidences - making me think the metal is cracked the whole way.

I'd remove paint from the replacement frame to check further, and try the testing aerosols Mzjo mentions.

zigzag · « **Reply #11 on:** 15 April, 2015, 12:15:37 am »

looking at where the crack starts (edge of the weld seam) my bet would be on the weld failure, not just paint.

The French Tandem · « **Reply #12 on:** 15 April, 2015, 05:38:02 am »

There is no reason for the paint to crack right on the weld, where the metal is very thick, and not elsewhere, where the metal is thinner. I have no experience with Orbit Al frames, but a few years ago, we had a very similar crack on a titanium frame. In our case, there was no possible dispute since there was no paint at all on the frame.

rafletcher · « **Reply #13 on:** 15 April, 2015, 08:35:53 am »

Yep, definitely a job for dye penetrant testing. Definitely looks to be a crack in the weld to me.

Wowbagger · « **Reply #14 on:** 15 April, 2015, 11:33:13 am »

I was going to ask what make of frame it was. It's a good job you've got those photographs of the first crack - I'm not impressed with the denial.

rabbit · « **Reply #15 on:** 15 April, 2015, 11:38:11 am »

Ooof cheeky buggers denying that it didn't happen in the first place! The original photos are obviously a cracked frame and I would expect this one to be the same.

Will follow this thread with interest. Keep us updated.

They clearly don't test their frames to "321-up power throughput" standard!

mrcharly-YHT · « **Reply #16 on:** 15 April, 2015, 11:41:36 am »

Was the first failure a crack in the frame or the dérailleur hanger?

The second one looks like weld failure to me. Butt-ugly welding, too. Most TIG welding looks ugly that that looks like a classic example of making the weld fat in an attempt to make it strong enough.

I am not an expert, but I would have said that tig welded aluminium is a poor choice of construction for a tandem. Aluminium simply doesn't cope with flexing and tig welds done like that concentrate the forces.

321up · « **Reply #17 on:** 16 April, 2015, 07:45:22 am »

Quote from: mrcharly on 15 April, 2015, 11:41:36 am

Was the first failure a crack in the frame or the dérailleur hanger?

in the frame

321up · « **Reply #18 on:** 16 April, 2015, 08:01:30 am »

Quote from: mzjo on 14 April, 2015, 03:17:08 pm

Go to your local welding supplier and get a set of crack testing aerosols. Interpreting the results sometimes needs a bit of experience but it will give you an idea with relatively little expense. Pity we didn't think of that with the first frame, you might have had evidence to present/dispute/discuss.
Normally there are three aerosols, cleaner, penetrant and developer but often over here users don't seem to bother about buying the cleaner.

Thanks for all the replys. I was going to ask about methods to make cracks in metal more visible - dirty oil works to some degree, hopefully the testing products recommended will be better.

I'll see if I can chip the paint off without marking the metal.

rafletcher · « **Reply #19 on:** 16 April, 2015, 08:21:01 am »

It shouldn't matter too much about marking the base metal - at least for dye pen testing, as the dye will penetrate down into any crack, and after cleaning and spraying with the white "developer" spray, any dye that's seeped down into the crack with be drawn out. The odd spot on surface crevices should be readily distinguishable from a line of a crack.

aidan.f · « **Reply #20 on:** 16 April, 2015, 09:49:10 pm »

Reckon you could blow bubbles out of that frame with some soapy water inside and a track pump connected to the seat post

jamesld8 · « **Reply #21 on:** 17 April, 2015, 07:03:28 am »

The crack you show in weld looks very similar to a crack in my old Ti frame around headtube, crack thro` tube and then into weld; with no paint on a Ti frame obvious that could only be the metal.

It`s worth removing BB too and looking inside as crack should be then visible inside too, countering any spurious ideas about `paint cracks` which IMO you most definitely do NOT have

Time for a refund and a steel frame ? (btw stick to your guns on that although my Ti frame was a replacement only warranty after some discussions I obtained financial refund instead as it was second failed frame, excellent service by retailer / manufacturer

)

321up · « **Reply #22 on:** 06 May, 2015, 02:38:08 pm »

My attempt to scrape off an area of cracked paint on the weld between the chainstay and bottom bracket mauled the malleable metal masking any possible metal fracture. Any suggestions for paint stripper that is safe on aluminium?

Any idea what's caused these small brown volcano like ruptures in the paint on two other welds?...

between chainstay and chainstay bridge...

betweed chainstay and dropout...

Somnolent · « **Reply #23 on:** 06 May, 2015, 03:29:06 pm »

At a guess I'd say inclusions of some sort of crap in the filler metal.

rafletcher · « **Reply #24 on:** 06 May, 2015, 03:50:47 pm »

Quote from: Somnolent on 06 May, 2015, 03:29:06 pm

At a guess I'd say inclusions of some sort of crap in the filler metal.

Or just mild steel particles that got onto the bare metal before spraying - adjacent grinding can do this.