Best way to fix chain stay 6061

Y u no TIG?

I am calling around to get the job done.
All I have is an old Lincoln arc welder. Its heavy and selling it, no 220 other then washer dryer room next to garage door.
So TIG welding theres no post-heat treatment?

rideit said:

Y u no TIG?

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There still is. But tig is easier to control heat while welding.

Ultimate Tensile Strength of T6 hardened 6061 is almost 3x that of the annealed (6061-O) condition of 6061 which is what you will produce if you weld your frame.
While getting a TIG weld repair made to the frame is fairly strait forward, performing the heat treatment to then return it from annealed condition to T6 hardness with the necessary jigging to keep frame in alignment is usually considered prohibitively expensive to save a single frame, cost to do so would likely exceed value of the frame unless you have access to the industrial equipment needed to heat treat batches of frames as manufactureres do. Sadly, an 6061-T6 frame is essentially financially totaled once it cracks.

GrayJay said:

Ultimate Tensile Strength of T6 hardened 6061 is almost 3x that of the annealed (6061-O) condition of 6061 which is what you will produce if you weld your frame.

6061-O Aluminum vs. 6061-T6 Aluminum :: MakeItFrom.com

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While getting a TIG weld repair made to the frame is fairly strait forward, performing the heat treatment to then return it from annealed condition to T6 hardness with the necessary jigging to keep frame in alignment is usually considered prohibitively expensive to save a single frame, cost to do so would likely exceed value of the frame unless you have access to the industrial equipment needed to heat treat batches of frames as manufactureres do. Sadly, an 6061-T6 frame is essentially financially totaled once it cracks.

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Not only that but if it was a weld that cracked or at a weld that's usually a good indicator that the bike is at the end of its life. I've had cracks professionally repaired from the highest skilled people in the land (SAPA extrusions) only to have cracks show up elsewhere in short order. The life of aluminum is finite.

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WHALENARD said:

Not only that but if it was a weld that cracked or at a weld that's usually a good indicator that the bike is at the end of its life. I've had cracks professionally repaired from the highest skilled people in the land (SAPA extrusions) only to have cracks show up elsewhere in short order. The life of aluminum is finite.

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I'd chock that up to shitty design though, instead of reaching the end of the fatigue life of the frame. Realistically you shouldn't approach the number of cycles for failure in a LONG time...but also realistically, there are probably areas of the frame that are under-designed or flawed in production, so they probably don't meet the intended specs for load limit, so normal riding causes the weakest link to fail, essentially a localized or micro-scale overload, vs number of cycles. It could obviously be a lot more complex than that, but unless we are talking 20 years old, I would be thinking overloads on an under-designed or under-manufactured frame.

Jayem said:

I'd chock that up to shitty design though, instead of reaching the end of the fatigue life of the frame. Realistically you shouldn't approach the number of cycles for failure in a LONG time...but also realistically, there are probably areas of the frame that are under-designed or flawed in production, so they probably don't meet the intended specs for load limit, so normal riding causes the weakest link to fail, essentially a localized or micro-scale overload, vs number of cycles. It could obviously be a lot more complex than that, but unless we are talking 20 years old, I would be thinking overloads on an under-designed or under-manufactured frame.

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A Turner 6-pack and Highline respectively. Certainly no expert on the engineering that goes into bike design, but they were pretty robust designs of their day.

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WHALENARD said:

A Turner 6-pack and Highline respectively. Certainly no expert on the engineering that goes into bike design, but they were pretty robust designs of their day.

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I broke the 6-pack due to running too long of a seatpost, my fault there. I didn't break the hiline, but there was an issue with the early model chainstays I believe. Chainstays, yokes and the dropout areas, have always been high stress and challenging for manufacturers to get right. Other than just pushing the bike too far (overloads), it would have to be production flaws or design flaws if cracks started showing up elsewhere. I did beat the hell out of that 6-pack and it's rear end, which stayed with me after I got a new front triangle. Never any other trouble from it. The Hiline I didn't have as long, but it seemed to be a very stout ride...a little too stout actually, in that it was just more than I ever really needed.