Reynolds 953 Chainstay Crack Repair
#1
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Reynolds 953 Chainstay Crack Repair
Hi,
Does anyone know if this cracked chainstay might be repairable? This is my friend's bike, which we believe is Reynolds 953. There's a small chance it's XCr.
Thanks
Does anyone know if this cracked chainstay might be repairable? This is my friend's bike, which we believe is Reynolds 953. There's a small chance it's XCr.
Thanks
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Interesting failure. Does it look like it started on the side and is there some lumpiness over there that might have been a hole that was filled or something?
I don't see why you couldn't TIG weld over the crack. You need ER630 rod and you will need to back-purge (rig up a separate supply of Argon to flow inside the frame to keep the back of the weld shielded).
You can also braze it apparently with "Meta-braze 140" rod and Meta-braze LT025 flux.
I've never done anything with 953, am just quoting from the Reynolds manual.
You'd probably also get away with a TIG braze repair using silicon bronze. This is not in the manual.
I don't see why you couldn't TIG weld over the crack. You need ER630 rod and you will need to back-purge (rig up a separate supply of Argon to flow inside the frame to keep the back of the weld shielded).
You can also braze it apparently with "Meta-braze 140" rod and Meta-braze LT025 flux.
I've never done anything with 953, am just quoting from the Reynolds manual.
You'd probably also get away with a TIG braze repair using silicon bronze. This is not in the manual.
#3
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We didn't take the crank off to get the best view of the entire crack. If viewed from the rear, there is cracked paint from about 11 o'clock to 7 o'clock. The crack is most pronounced from about 3 o'clock to 6 o'clock. I didn't notice anything that looks like a filled hole.
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I assume that the current owner isn't the original purchaser... and that the manufacturer/builder is no longer around or interested in repairing this frame. Andy
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Welding the crack is the kind of repair that relegates the bike to coffee shop use in my opinion. I suspect it started at a weld defect. It's an uncommon failure.
The proper repair is remove/replace the chainstays. And tbh, I would want the entire rear triangle replaced.
I don't know what the problem is with the original builder, but finding out what the material is should be done somehow.
The proper repair is remove/replace the chainstays. And tbh, I would want the entire rear triangle replaced.
I don't know what the problem is with the original builder, but finding out what the material is should be done somehow.
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At some point it would be interesting, to me at least, on this preference. I can speculate but my guesses don't matter.
I don't weld so my thoughts of fixing are either patches or replacement of the stay. Andy
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anyone know if 953 is magnetic?
on edit: unfortunately it is, otherwise it would be easier to tell what the material was, or wasn't
on edit: unfortunately it is, otherwise it would be easier to tell what the material was, or wasn't
Last edited by unterhausen; 09-24-20 at 08:07 PM.
#9
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Welding the crack is the kind of repair that relegates the bike to coffee shop use in my opinion. I suspect it started at a weld defect. It's an uncommon failure.
The proper repair is remove/replace the chainstays. And tbh, I would want the entire rear triangle replaced.
I don't know what the problem is with the original builder, but finding out what the material is should be done somehow.
The proper repair is remove/replace the chainstays. And tbh, I would want the entire rear triangle replaced.
I don't know what the problem is with the original builder, but finding out what the material is should be done somehow.
Last edited by cuevélo; 09-25-20 at 07:35 AM. Reason: spelling
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Otherwise I guess you need an X-ray fluorescence gun.
Columbus do suggest a slightly different welding rod for XCr. But it would be worth investigating whether there's really that much difference.
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Ok here's my idea. . Buy a piece of 4130 the same diameter or slightly lager than the ID of the chainstay, cut to about an inch long if the diameter is larger machine it until it fits inside. Clean out the inside of the chainstay , strip the paint grind the crack until clean metal shows. Insert the 1 inch 4130 tube braze in place with either 45% silver or nickel silver. file sand and repaint.
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I feel like an internal repair is virtually impossible to do well.
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I'd agree given the access challenge through the BB shell really limits the situation. I did mention an outside patch earlier but as usual my pragmatic but aesthetic bending suggestions are often not heeded. Andy
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Kind of looks like there was some kind of misalignment when the frame was made, the weld shrunk and that area has been under constant stress since then. Deffo worth pulling the BB and trying to get a look up the inside of the stay to see how far it's progressed internally..
Would I get it repaired with weld? Maybe if it was expensive, nice and you couldn't get another one but I'd be watching it like a hawk after that.
Would I get it repaired with weld? Maybe if it was expensive, nice and you couldn't get another one but I'd be watching it like a hawk after that.
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Kind of looks like there was some kind of misalignment when the frame was made, the weld shrunk and that area has been under constant stress since then. Deffo worth pulling the BB and trying to get a look up the inside of the stay to see how far it's progressed internally..
Would I get it repaired with weld? Maybe if it was expensive, nice and you couldn't get another one but I'd be watching it like a hawk after that.
Would I get it repaired with weld? Maybe if it was expensive, nice and you couldn't get another one but I'd be watching it like a hawk after that.
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The weld always shrinks and gets misaligned there when it's made. You just bend the stay back. There's nothing to hold it in much constant tension there. I don't know the cause of the failure but I'd guess something went a little bit wrong with the weld resulting in a bit of porosity or something.
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The crack probably started at the toe of the weld at the 3 o'clock position and traveled in a straight line around the stay, which is why it is so far away from the weld at the 6 o'clock position. As for the internal repair suggestion, this is a welded frame and probably has only a small vent hole in the bottom bracket. It is nothing like a lugged bottom bracket, where the whole chainstay is accessible through the bottom bracket.
The crack could probably be welded, as long as aesthetics are not a concern, but there is a high chance of weld contamination from whatever is inside the stay. The proper repair is to replace the stay and maybe both, if you want them to match. Is the frame worth the cost of repair?
The crack could probably be welded, as long as aesthetics are not a concern, but there is a high chance of weld contamination from whatever is inside the stay. The proper repair is to replace the stay and maybe both, if you want them to match. Is the frame worth the cost of repair?
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There is no other place for a crack to start other than the weld. Unless the tube suffered some insult that is not apparent in the picture we have. But it clearly started out of the picture, and probably on the side of the bb just at the edge of the weld. It then traveled perpendicularly to the load path. That weld looks shady to me, like there is poor penetration at the edge. But everyone on the internet is a weld critic.
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There is no other place for a crack to start other than the weld. Unless the tube suffered some insult that is not apparent in the picture we have. But it clearly started out of the picture, and probably on the side of the bb just at the edge of the weld. It then traveled perpendicularly to the load path. That weld looks shady to me, like there is poor penetration at the edge. But everyone on the internet is a weld critic.
As an expert from personal experience in how not to do TIG welding one thing that can catch you out with a joint like that is the arc leaping off to the side when you start up. The HF start is very good at finding its way to earth sometimes via strange routes. It can do that intermittently sometimes and can either burn the tube a bit (there's less argon over there) or even start melting it if you don't notice in time. It takes probably less than a second to liquefy a bit of bicycle tubing with a TIG arc that isn't being fed fresh rod to cool it down especially if it's longer than usual. The welder will crank up the voltage automatically if the arc is long to help ruin your day.