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PostPosted: Mon Sep 02, 2013 1:51 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8221
Location: New Forest, UK
Hmm, that is going to be difficult as there is no cylindrical end to the headtube to shrink a band around.

I suspect that frame is relegated to wall art.


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PostPosted: Mon Sep 02, 2013 3:12 pm 
Devout Dirtbag

Joined: Mon Sep 13, 2010 12:59 am
Posts: 112
Location: leicester
mine was on the top lug of the headtube- i'll try and put a pic.. cheers


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PostPosted: Mon Sep 02, 2013 3:14 pm 
Retro Guru

Joined: Fri Jan 28, 2011 11:23 pm
Posts: 506
I was thinking that
well, we're not dead yet, not so far from my mates is a welder who repaired an old master of mine that had a torn derailleur hanger, so I'll see what they say whilst I'm there, if I un bond the tubes then repair


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PostPosted: Mon Sep 02, 2013 5:32 pm 
Retro Guru

Joined: Tue Oct 16, 2012 4:16 pm
Posts: 1568
Location: NOTTINGHAM
Seemingly a fairly common trait with these vintage Alans - this one was on ebay yesterday....

I've read that you can bond a collar as already suggested, but in addition you can drill a hole at the top of the crack which in theory should stop it spreading further. Whether you could weld a collar on the inside rather than the outside i'm not sure but it would give you more contact area to weld / bond to. Might need to thin the headset cup down a bit but probably worth a go.
Other option may be to weld a strap externally but as a half circle.


Attachments:
Alan Split.JPG
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PostPosted: Mon Sep 02, 2013 6:13 pm 
Retro Guru

Joined: Fri Jan 28, 2011 11:23 pm
Posts: 506
thanks, that split looks almost identical!
what did the ebay one go for?

cheers


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PostPosted: Mon Sep 02, 2013 6:18 pm 
retrobike rider
retrobike rider
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Joined: Tue Jan 29, 2008 11:04 pm
Posts: 1802
Location: A wretched hive of scum and villainy...
Drilling a stress relief hole might help on some frames, but on your blue frame, the crack's already all the way through the lug. :cry:

The blue middle section of the headtube is a separate tube bonded in. It should be safe from cracking, as the headset cup only fits into the lower silver cast section, which is cracked.

If you can find out which alloy the lug castings are made with, and de-bond the headtube, it would be possible to weld up the crack with the right filler rod.
Any welding around the headlug without separating the tubes will also kill any epoxy bonds in the area, making it even less rideable; only 80ºC needed.

If I understand ALANs correctly, unlike Vitus bonded frames, the tubes are threaded into the lugs and bonded so in order to separate the lower head lug you'd have to de-bond the DT/BB and TT/ST junctions too.
(Not sure if they are standard thread on both ends RH/RH, or RH/LH like turnbuckles.)

Then sand, clean, acetone and re-bond the top tube, down tube and headtube junctions simultaneously using a good quality structural epoxy, then hold the frame in a jig to keep the alignment while the glue sets.

IMHO probably not really worth it. :(

All the best,


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PostPosted: Mon Sep 02, 2013 6:38 pm 
Retro Guru

Joined: Tue Oct 16, 2012 4:16 pm
Posts: 1568
Location: NOTTINGHAM
saarf wrote:
thanks, that split looks almost identical!
what did the ebay one go for?

cheers


http://www.ebay.co.uk/itm/Classic-Light ... 27d7208802

Didn't meet it's reserve as part of a 3 bike combo!


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PostPosted: Mon Sep 02, 2013 6:41 pm 
Retro Guru
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Joined: Sun Mar 17, 2013 10:25 pm
Posts: 1262
FINNEY1973 wrote:
...Didn't meet it's reserve as part of a 3 bike combo!



Quote:
I've just noticed a small crack on the front of the Alan see pic



Looks like it's been there for a long time :shock:


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PostPosted: Mon Sep 02, 2013 7:49 pm 
Retro Guru

Joined: Tue Oct 16, 2012 4:16 pm
Posts: 1568
Location: NOTTINGHAM
47p2 wrote:
FINNEY1973 wrote:
...Didn't meet it's reserve as part of a 3 bike combo!



Quote:
I've just noticed a small crack on the front of the Alan see pic



Looks like it's been there for a long time :shock:


Very much so, not something that you just notice unless of course you have had the bikes in a shed for years being unused as those 3 bikes sort of suggest.

Always liked these old Alans, this has put me off owning one though I must admit. Seem beautifully made but a little fragile as the years pass - real shame.


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PostPosted: Mon Sep 02, 2013 7:56 pm 
Retro Guru
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Joined: Sun Mar 17, 2013 10:25 pm
Posts: 1262
We have some very poor road surfaces where I cycle and my Alan takes it all in its stride.

I suspect a poorly fitted headset that has been forced could be a major contributor to this problem


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