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TiHabanero 09-20-18 04:40 PM

Frame Repair Question
 
An acqaintance of mine approached me about repairing a steel frame that has a crack in the seat tube that runs length wise about 3 inches and the right side chain stay that has a U shaped crack between the BB and chain stay bridge. I told him that will be super labor intensive and perhaps just the chain stay can be replaced and the seat tube crack filled in and wrapped with a piece of metal and brazed in place. Is this a viable approach?

Second question: How is it people find out I have build a few frames and they come to me with their broken frames for repair? Built 3 frames and this is the 4th person seeking a repair.

pwyg 09-21-18 07:35 PM

what you are describing sounds bad, First if you are attempting to band aid a crack is something I would never consider. You need to approach from the point of replacing the entire tube or tubes. Tig welded steel frames that crack along the weld can easily be v grooved to increase the weld contact area for the filler material then build a larger than normal fillet. These will generally last longer than Tig joints in general. As for what you got going on I need to see what is going on to evaluate the repair. Just to let you know I have seen builders with 20 years in the craft screw up basic repairs because they have no clue other than how to put one together in a fixture.

unterhausen 09-22-18 11:53 AM

I think many repairs are more difficult than building a new frame. One issue most people disregard is that there is usually a reason why the frame broke, and that reason is not always something you can fix. The last two repairs I did were like that. One had a broken head tube and the other had a crack in the seat stay/seat tube junction.

TiHabanero 09-23-18 11:31 AM

Unterhausen, were you able to determine what caused the failures?

unterhausen 09-23-18 01:08 PM

In the case of the seat stay, the stress relief hole at the bottom of the seat lug slot was far too close to the edge of the seat stay. In the case of the head tube, the top and down tubes were clocked, so the miter didn't close. It certainly didn't help that the lug had been thinned so much

I could have fixed the seat stay issue by replacing the stays. Too much work, but that's the way I would quote it in the future and let the customer decide. In the case of the head tube, it's really a gonner.

Andrew R Stewart 09-24-18 10:15 PM

What kind of reputation are you comfortable with? A lot of us "more then hobby but not full pros" do some repairs that in hindsight we would reconsider later. It's part of the curve we learn on. Where along that curve we find our sweet spot changes as we look back.

One thing that I have found to be the case with any repair is that it takes longer then I initially plan on. Then when the results don't really meat my personal standards I question my initial decision. Over the years I've done less and less repairs, choosing those where I find gratification in (because the $ don't equal my efforts usually).

I agree with Eric's thoughts on why the cracks happened in the first place. Over cooked during brazing, twisted alignment "corrected" at the factory, poor initial fit up or other won't be fully corrected by a quickie repair. Unless the frame is something special, the customer isn't hoping for a rider or you just want to learn at any cost I'd question this job. Andy


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