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Old 10-28-10, 06:26 PM   #1
denverartist
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Crack in vintage Colnago dropout - can it be repaired?

On the right rear dropout, just aft of the chainstay joint, my old Colnago Super has developed a crack. Looking closely, under a respray job, I think there was a previous repair. The crack is on one side only, outer side, does not go through, and does not move or flex. I can ride the bike, but obviously can't live with this.
Can this be mig welded or does one have to rebraze?

Thanks for any advice. Many have dealt with this type of question before on this forum, I'm sure.

Pete


Last edited by denverartist; 10-28-10 at 06:35 PM. Reason: add picture
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Old 10-28-10, 06:29 PM   #2
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picture?
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Old 10-28-10, 06:34 PM   #3
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It would probably be better to post this to the Framebuilder's forum. And Fiets is right: a picture is worth a 1000 words.

My WAG is that it could be rebrazed, but if it's already been repaired it may need complete dropout replacement.
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Old 10-28-10, 06:36 PM   #4
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Picture added.
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Old 10-28-10, 06:38 PM   #5
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Tig is far better than mig for something like this. If it has been previously repaired by gas welding, mig or brazing, that really doesn't stop a successful Tig repair. The old repair should be ground out first, of course

I don't know if your picture is showing, here is the url: http://i111.photobucket.com/albums/n...opoutcrack.jpg


I don't see the evidence of previous repair, unless it's on the back. That looks like it should be easy to fix, TIG (GTAW) is the way to go. I suppose you might find a really good mig welder that could do it, but there is brass right beside it that might cause problems.

Last edited by unterhausen; 10-28-10 at 06:43 PM.
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Old 10-28-10, 06:49 PM   #6
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Originally Posted by unterhausen View Post
Tig is far better than mig for something like this. If it has been previously repaired by gas welding, mig or brazing, that really doesn't stop a successful Tig repair. The old repair should be ground out first, of course

I don't know if your picture is showing, here is the url: http://i111.photobucket.com/albums/n...opoutcrack.jpg


I don't see the evidence of previous repair, unless it's on the back. That looks like it should be easy to fix, TIG (GTAW) is the way to go. I suppose you might find a really good mig welder that could do it, but there is brass right beside it that might cause problems.
Beat me to it.
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Old 10-28-10, 07:25 PM   #7
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Thanks to responders. I will look for a TIG welder, probably know a guy. I'll take care of the painting myself, after.

Peter
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