Is it feasible to repair a crack in a frame around the seatpost clamp? Being an aluminium frame I understand soldering is problematic. It doesn't matter if seatpost is fixed in place as per a solution involving epoxy/some kind of wrap etc.

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    This is toast, bin it. – Vladimir F Jan 28 at 15:23
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    Also, that's not a 'crack by seatpost clamp', it's right through the top tube/seat tube intersection – Argenti Apparatus Jan 28 at 16:15
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    Bike is a Boardman Comp and is most definitely alloy. No real financial value - I can remove the expensive bits that I added - however huge emotional attachment from sharing 30k+ kms.... – gorytus Jan 28 at 16:41
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    Do check what frame warranty Boardman offers - and see if you're covered. I would not ride that bike as-is, and I doubt its weldable. – Criggie Jan 28 at 18:54
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    On Al frames cracks tend to follow weld lines, but these don't. On a Al frame that has no visible welds, there must be filler applied over the welds then sanded smooth. I wonder if the filler and paint has cracked but not the underlying Al frame. (of course there may be a crack in the Al, but the surface crack is in a different place.) – Argenti Apparatus Jan 28 at 19:54

Is it feasible to repair a crack in a frame around the seatpost clamp?

1. possible to do easily or conveniently.
2. likely; probable.

It is possible to repair an aluminum frame. It is not easy or convenient.

It's all about how much effort/money you are willing to put into this project.

Finding someone with a gas tungsten arc welding rig who would be willing to weld on your frame is one thing. Finding someone who knows what they are doing is something else.

Here is a discussion on a welding forum with an intelligent answer on aluminum bicycle frame repair. Here is a snippet of the conversation relating to repairing a frame:

Any repair should be made via gtaw (tig-heliarc) by an EXPERIENCED welder. If the frame is truely 7005 then 5180 would be the filler material of choice. This will allow the frame to undergo heat treatment to restore it to its original condition. If the frame is actually a t6 alloy more than likely you should use a 4643 filler which again will allow heat treatment.....if you wish to repair without heat treatment use 5356 which will work on either alloy but without heat treatment it will never be in the condition it was when produced.

The most feasible solution is to see this as an excellent opportunity to upgrade.

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    +1, right answer, but it would be good to say more explicitly that one of the major hurdles to repairing it being cost effective is stripping, heat treating, and refinishing. – Nathan Knutson Jan 28 at 18:06
  • @NathanKnutson The quote mentions heat treatment. The linked conversation refers to stripping and refinishing. Thanks for making these steps clearer. – David D Jan 28 at 18:19
  • Good information on heat treatment. The quote makes it clear that it's necessary to know the original aluminum alloy to make a proper repair. – Weiwen Ng Jan 28 at 21:14

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