Rebrazing a frame?
#1
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Rebrazing a frame?
I'm bring a question to "Framebuilding" that I already raised in "Bicycle repair." One of the regulars there suggested I take it to you guys as well. Following I quote what I wrote:
"My project to support my friends who want their 50 year old steel frames to be more usable and to stem the effects of rust has been about vintage frames. Now it's about a more serious repair. While dismantling the bicycles and trying to get out a stuck stem, the steer tube became loose in my hand (stem inside). The brass remained in the joint only in the bottom ⅛ inch of the steerer to crown interface - only tacked? One friend with some knowledge suggested one incompetent braze calls into question all of the joints on both frames.
We have discussed it with the framebuilder who will strip, align and repaint the frames. I raised the question of the joints, and he says he can just rebraze all the joints. My friend is in agreement, and I am not so sure, having read about the base steel being weakened due to additional heating cycles.
Is rebrazing the entire frame inherently risky? Can it be mitigated or even prevented by a skilled builder? What are the issues?
My friends who own and wish to continue riding these are not young. They are capable riders of sound frames, but could be badly injured if dumped on the ground."
What do you guys think?
"My project to support my friends who want their 50 year old steel frames to be more usable and to stem the effects of rust has been about vintage frames. Now it's about a more serious repair. While dismantling the bicycles and trying to get out a stuck stem, the steer tube became loose in my hand (stem inside). The brass remained in the joint only in the bottom ⅛ inch of the steerer to crown interface - only tacked? One friend with some knowledge suggested one incompetent braze calls into question all of the joints on both frames.
We have discussed it with the framebuilder who will strip, align and repaint the frames. I raised the question of the joints, and he says he can just rebraze all the joints. My friend is in agreement, and I am not so sure, having read about the base steel being weakened due to additional heating cycles.
Is rebrazing the entire frame inherently risky? Can it be mitigated or even prevented by a skilled builder? What are the issues?
My friends who own and wish to continue riding these are not young. They are capable riders of sound frames, but could be badly injured if dumped on the ground."
What do you guys think?
#2
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I am no expert but do know that a good brazed joint needs everything to be very clean. Any gaps in the joint when it was first built will almost certainly be corroded and far from squeaky clean.
So I cannot see how you could re-braze a joint without dismantling, cleaning and fluxing and this would require a further two heat cycles.
So I cannot see how you could re-braze a joint without dismantling, cleaning and fluxing and this would require a further two heat cycles.
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I do read/hear of joint rebrazing done with what I have thought is poor clean up, "that's what the flux is for" was one comment I remember. Not what I would want to solely rely on.
We know that one joint (and perhaps the most structurally critical one) wasn't brazed well. We don't know if any others are too. We don't know of the builder's intentions yet, their skill, experience and reputation. At this point of information I would be very hesitant to have the complete frame go through another brazing cycle (tubing brand/spec, braze filler used in the build are open data points still). Repair of the failed steerer/crown is pretty straight forward but the other joints might not need anything. At the least i would want to strip the frame of paint and do some very close looking at before anything else. Andy
We know that one joint (and perhaps the most structurally critical one) wasn't brazed well. We don't know if any others are too. We don't know of the builder's intentions yet, their skill, experience and reputation. At this point of information I would be very hesitant to have the complete frame go through another brazing cycle (tubing brand/spec, braze filler used in the build are open data points still). Repair of the failed steerer/crown is pretty straight forward but the other joints might not need anything. At the least i would want to strip the frame of paint and do some very close looking at before anything else. Andy
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I don't really think that will be successful
I don't know of any evidence that extra heat cycles will hurt a steel frame, although it's widely believed. Just received wisdom as far as I know.
I don't know of any evidence that extra heat cycles will hurt a steel frame, although it's widely believed. Just received wisdom as far as I know.
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I have a bike boom Raleigh Competition that had the shift boss just barely tacked on. Big visible gap. I already knew the bike was a blast to ride on the local gravel boars but I wondered if it was indeed safe at the hill bottoms with their deep washboard. (Having nearly lost my life and suffering lifelong consequences, I'm gun shy re: frame breakage.)
Took it to TiCycles and asked Dave Levy to send it out to be stripped then give it a good inspection. He found big gaps in many of the logs. I don't know his prep work but he told me he flowed in brass like a new build, saying jokingly that the excellent paint job was what kept the bike together. (I wonder if that paint kept the steel surface clean.)
I trust his judgement and work. He knows steel construction and repair, from bikes to race cars. He has seen just about everything. I haven't put a lot of miles on the bike but I do trust it. (I've backed off most gravel because rough roads aggravate the consequences I mentioned above.)
Took it to TiCycles and asked Dave Levy to send it out to be stripped then give it a good inspection. He found big gaps in many of the logs. I don't know his prep work but he told me he flowed in brass like a new build, saying jokingly that the excellent paint job was what kept the bike together. (I wonder if that paint kept the steel surface clean.)
I trust his judgement and work. He knows steel construction and repair, from bikes to race cars. He has seen just about everything. I haven't put a lot of miles on the bike but I do trust it. (I've backed off most gravel because rough roads aggravate the consequences I mentioned above.)
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If the issue is gaps at the shoreline, brass will definitely flow in. Silver needs better cleaning, but brass flux is very active and brass will flow okay if things are less than perfectly clean. It probably isn't possible to adequately clean inside the lug. Shorelines are usually full, if they aren't it's evidence of malpractice and I would seriously consider cutting up the frame.
This is one reason I don't understand the attraction people feel for '70s Raleighs. Some of them are fine but it's the luck of the draw if you get one of those. If they needed someone to make frames they would go down to the pub and drag a drunk back to the factory.
This is one reason I don't understand the attraction people feel for '70s Raleighs. Some of them are fine but it's the luck of the draw if you get one of those. If they needed someone to make frames they would go down to the pub and drag a drunk back to the factory.
#8
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I do read/hear of joint rebrazing done with what I have thought is poor clean up, "that's what the flux is for" was one comment I remember. Not what I would want to solely rely on.
We know that one joint (and perhaps the most structurally critical one) wasn't brazed well. We don't know if any others are too. We don't know of the builder's intentions yet, their skill, experience and reputation. At this point of information I would be very hesitant to have the complete frame go through another brazing cycle (tubing brand/spec, braze filler used in the build are open data points still). Repair of the failed steerer/crown is pretty straight forward but the other joints might not need anything. At the least i would want to strip the frame of paint and do some very close looking at before anything else. Andy
We know that one joint (and perhaps the most structurally critical one) wasn't brazed well. We don't know if any others are too. We don't know of the builder's intentions yet, their skill, experience and reputation. At this point of information I would be very hesitant to have the complete frame go through another brazing cycle (tubing brand/spec, braze filler used in the build are open data points still). Repair of the failed steerer/crown is pretty straight forward but the other joints might not need anything. At the least i would want to strip the frame of paint and do some very close looking at before anything else. Andy
So in the experience of frame builders here, does such an approach done well result in full restoration of the integrity of the frame? The frame material is straight 531 throughout (based on remnants of the original sticker) and the rider weights are both about 170#.
#9
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If the issue is gaps at the shoreline, brass will definitely flow in. Silver needs better cleaning, but brass flux is very active and brass will flow okay if things are less than perfectly clean. It probably isn't possible to adequately clean inside the lug. Shorelines are usually full, if they aren't it's evidence of malpractice and I would seriously consider cutting up the frame.
This is one reason I don't understand the attraction people feel for '70s Raleighs. Some of them are fine but it's the luck of the draw if you get one of those. If they needed someone to make frames they would go down to the pub and drag a drunk back to the factory.
This is one reason I don't understand the attraction people feel for '70s Raleighs. Some of them are fine but it's the luck of the draw if you get one of those. If they needed someone to make frames they would go down to the pub and drag a drunk back to the factory.
In my bike history I had a lower-end 1969 Falcon with straight 531, and except for having a rough and not lively ride, it had some lugs where the joints were not fully filled. I didn't have a problem with it, but I didn't mourn loss of the bike when it was stolen. I did mourn loss of the NR derailleurs, broken in B15 and Zeus chainset I had added, but I was only 17 at the time. Next target was a PX-10. Currently I have a 1973 Super Course which I have not built. It has a loose compression tube inside the seatstay bridge. I'd like to fix it, build the frame and sell the bike to move it and some extraneous used parts, but I'm not sure it's worth the $$$ to have the paint repaired afterwards. Based on my Falcon experience I don't believe it will give a ride I will like.
Several shops back in those days regaled me with that story about Raleigh factory workers out in the pub. You wanted to get a Tuesday or Wednesday bike, not a Monday or especially not a Friday!
Last edited by Road Fan; 01-08-21 at 09:50 AM.
#10
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Thanks a bunch for weighing in! I wish we did not already have something broke, and I wish the break was due to abuse or overloading, where we could expect that there aren't more problems. The builder understands the concern and is an experienced, practical guy - I'd be surprised if he does not share that viewUnfortunately it seems to be poor workmanship, so we worry how far that problem goes. If the builder thinks the repairs should not be done I would echo that cause strongly to my friends. The frames have very high sentimental value to my friends. Otherwise I'd press them to let the iron go. There is another design flaw: the spacing between the chainstays barely clears the 27 x 1 ¼ road tires - Panasonics of some smooth-treaded sort. We'll ask them if they can dimple it.
Last edited by Road Fan; 01-09-21 at 11:30 AM.
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I imagine the fork was built by a different person than the frame, if that gives any solace.
For some reason people have problems with steerers. Takes a lot of heat, but most people don't have a problem providing that. But at least people should look for filler at the brake hole.
Hollow crowns are nice because you can look through the blade sockets at the steerer. I wouldn't be happy unless there was a visible internal fillet. Fortunately I never have had that issue.
For some reason people have problems with steerers. Takes a lot of heat, but most people don't have a problem providing that. But at least people should look for filler at the brake hole.
Hollow crowns are nice because you can look through the blade sockets at the steerer. I wouldn't be happy unless there was a visible internal fillet. Fortunately I never have had that issue.
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#12
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Thanks, all, for your input.
#13
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