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Old 01-11-13, 09:08 PM   #1
no_bike
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Crack in weld?

Just received a new tig welded chromo frame only to find something suspicious in one of the welds. Where the drive side chainstay meets the bottom bracket there is a tiny uneven black line that looks suspiciously like a crack. It's difficult to view well and even more difficult to take a coherent photo of. I will try to ask around locally but I feel like I need either frame builders' advice or veteran welders' advice. This frame has never been built up and is brand new. I'm trying to develop some more context to decide whether to contact the mfg. and dealer. If it's a crack that will grow and fail or some bizarre way the paint settled... I understand such cracks can develop when too much heat is applied during assembly and they continue to grow? I know the photo is poor but it's the best I could do and I figure frame builders know enough...

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Old 01-11-13, 10:08 PM   #2
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Send the pic to the builder.
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Old 01-11-13, 10:32 PM   #3
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I don't think it's a crack but just bad welding because I see a pinhole on the nondriveside stay and even the beads connecting the stays to the BB shell are just inconsistent compared to the seat tube to bb. The toes of the weld on the driveside stay appear to be cold and not enough amperage was given. The spot of concern I'm not sure is a crack but could be excessive filler or where got the tungsten stuck to the bead while welding. I'd worry more about the toe of the welds just below that "cracked" section. But overall I've seen worse looks to be just a asian built production welded frame. If it was supposed to be a high quality frame that cost some coin from a well known company then I'd complain. That's just my .02 from a TIG welder.
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Old 01-12-13, 06:14 PM   #4
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So, the area in question could be a kind of void space but not a crack? And this kind of void doesn't necessarily become a growing crack? Also, I was able to get a better pic. The line pretty much meets the toe of the weld (if I'm using "toe" correctly) and you mentioned the toe could be something to worry about?

I'm incredulous that I found this "crack" extremely soon after removing the bubble wrap and yet the mfgs. didn't see it. Hopefully they saw it and decided it's inconsequential.

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Old 01-14-13, 05:08 AM   #5
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It looks a bit like a cracked tack and the welder didn't go over it when finish welded. I find flaws in my powder paint jobs that require stripping at about the same frequency as I miss a small weld like that. It happens.

It won't propagate but could be a source of future corrosion issues.
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Old 02-01-13, 11:48 AM   #6
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Looks like the welder didn't tie in the end of the weld to the beginning of the bead really well, or was a bit cold and "globby" when he started his weld - maybe added the filler too soon before the puddle was fully established... Or as noted, it could be the weld crater overlapping a tack.... Been 13 years since i worked as a code welder so my "eye" may be a little rusty...
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