shovelon
Senior Retro Guru
It is easily weldable, but you need to get the correct seatpost diameter and run at least 4 inches into the tube after repair. It will take a good 6 months to regain some good age hardening, so a long insertion is best.
All alum frames tend to do this eventually. Proflexes in particular because they have the short seat mast, and GT-idrives because of the window they machined just under the clamp area.
Go see your local welder and see what they say. If they have 5356 filler or equivelant heat treatable filler, and do not overheat during weld, it will work great. I have collapsing mandrels that retain the original inside diameter, but you may have to drum sand the penetration from the inside it your welder does not have them. I have 27.2 for proflex, 31.8 for trek and GT, and 30.9 for Mountain Cycle.
Seatpost shims are the devil!
All alum frames tend to do this eventually. Proflexes in particular because they have the short seat mast, and GT-idrives because of the window they machined just under the clamp area.
Go see your local welder and see what they say. If they have 5356 filler or equivelant heat treatable filler, and do not overheat during weld, it will work great. I have collapsing mandrels that retain the original inside diameter, but you may have to drum sand the penetration from the inside it your welder does not have them. I have 27.2 for proflex, 31.8 for trek and GT, and 30.9 for Mountain Cycle.
Seatpost shims are the devil!