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


feasible:
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.