Alan Record Headtube crack
- Thread starter saarf
- Start date
FINNEY1973
Senior Retro Guru
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.
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
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,
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,
FINNEY1973
Senior Retro Guru
saarf":2u8e8ebg said:
http://www.ebay.co.uk/itm/Classic-Light ... 27d7208802
Didn't meet it's reserve as part of a 3 bike combo!
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
FINNEY1973
Senior Retro Guru
47p2":2le3wpvt said:
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.
