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Old 09-18-10, 06:07 PM   #1
gargamel
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Disconnected Braze-On: To JB Weld or not to JB-Weld?

I have an older Raleigh Record frame which is shaping up to become a nice FG conversion. One issue though is that the braze-on that would normally hold the rear brake assembly is disconnected on the left side.




(Had a bit of trouble getting my little point-and-shoot to focus properly)

Although I won't be using a rear brake, I've been told by my shop guy that it's a structural issue; if I don't repair it, it may create problems elsewhere. But he wasn't sure whether the job absolutely needed to be taken to an auto shop for brazing, or if it could be done with JB Weld.

On the one hand, having it brazed by a pro would presumably be rock solid.

On the other hand, JB Weld would be cheap and quick. I've never used it before, but I've heard it's very strong. Also, this method would avoid destroying a large area of the paint job. As you can see, this frame isn't exactly pristine, but a big black blemish is still not preferable.

What do you guys think?
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Old 09-18-10, 06:13 PM   #2
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jb weld is not suitable
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Old 09-18-10, 06:14 PM   #3
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What's loose is called the brake bridge and it is indeed both a rear brake attachment point and a structural reenforcement for the rear triangle. I would not trust any epoxy to bond it adequately. Have it braze properly.

Since the brazing will ruin the paint around it, you will have an excuse to have the entire frame cleaned up and repainted. Based on your picture, it seems to need it

One other consideration, did the original joint just break from fatique or poor assembly or did it fail from rust damage? If the later, maybe putting any work at all into this frame isn't a good idea.
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Old 09-18-10, 06:21 PM   #4
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From your picture it looks like the original joint was not sound. I would think any number of shops could fix that for a very reasonable price. Touch-up paint is cheap and widely available.
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Old 09-18-10, 06:27 PM   #5
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JB Weld will not work on this application, you need to have that brazed. The part looks heavily rusted. Before the part can be brazed, ALL the rust must be removed. Brazing will also burn off a lot of the existing paint. Depending on how much rust there is, this frame may not be worth the trouble.
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Old 09-18-10, 06:30 PM   #6
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One other consideration, did the original joint just break from fatique or poor assembly or did it fail from rust damage? If the later, maybe putting any work at all into this frame isn't a good idea.
I bought the frame off of craigslist for $40. So I'm not sure about how this happened, but I'm trying not to put a lot of money into it anyway.

Still, the consensus here seems to be that taking it to the shop is the way to go. Thanks for the replies everyone!
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Old 09-18-10, 10:37 PM   #7
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The Record is a pretty common and you could probably find a clean frame for less than it would cost for the repair and repaint.
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Old 09-18-10, 11:52 PM   #8
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Before trying to repair that you might want to check rear wheel aligment carefully with whatever setup you plan to use. May have popped off by trying to spread the dropouts.
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Old 09-19-10, 12:59 AM   #9
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By the looks of those blisters in the paint, I'd say the separated brake bridge is a symptom of a larger rust issue. To answer the initial question - I'd avoid epoxy.
I would investigate the rust throughout the frame and determine whether the frame is worth salvaging before committing too much money to the project. It costs some (but not much) money to strip paint and treat the rust. If you have several spots that are rusted completely through the tubing, I personally would not want to ride it. On the other hand, if the rust is just scale and pitting, then an acid dip and a rattle can paintjob might be workable.
However, your total cost at that point may be more than the cost of simply finding a frame in better condition.

Last edited by canyoneagle; 09-19-10 at 01:02 AM.
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Old 09-19-10, 05:36 AM   #10
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Before trying to repair that you might want to check rear wheel aligment carefully with whatever setup you plan to use. May have popped off by trying to spread the dropouts.
Which is why you use lots of strapping tape around the brake/chain stay bridges before attempting such a thing.
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Old 09-19-10, 08:27 AM   #11
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The term JB "Weld" is a triumph of BS merchandising. Total lie. JB "Weld" has NOTHING to do with welding -- it is a very successfully merchandised brand of epoxy glue.
Think about that. Do you really believe you can glue a previously welded frame back together and expect it to hold?

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Old 09-19-10, 08:38 AM   #12
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you have to take it down to bare metal, cleaned to a shine,flux, and then re braze the joint,
clamping it till the brazing material cools.

If you have tools to do brazing, you wouldn't consider glue.

if not oxy-acetylene ,then at least oxy-mapp , gas torch for heat.

Last edited by fietsbob; 09-19-10 at 01:56 PM.
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Old 09-19-10, 01:53 PM   #13
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JB-weld is an epoxy with 2000-lb/sq.in strength under ideal conditions (fully cleaned mating surfaces with 0.1mm or less clearance)

Brass used in brazing has 60000-lb/sq.in strength

Anyone who can do basic math can see the difference in how well each would hold together a joint.
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Old 09-19-10, 02:06 PM   #14
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It appears to be a failure in the weld itself... the frame has some rust issues but that bridge has pulled away cleanly from the seat stay.

Was probably built on a Friday afternoon...
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Old 09-20-10, 01:22 PM   #15
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Follow-up: Where should I go to get this kind of work done? I'm guessing most bike shops aren't set up for this sort of thing, right? I called a few auto repair shops in my area and they seemed sort of confused and unsure if they'd be able to do it.
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Old 09-20-10, 02:05 PM   #16
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Follow-up: Where should I go to get this kind of work done? I'm guessing most bike shops aren't set up for this sort of thing, right? I called a few auto repair shops in my area and they seemed sort of confused and unsure if they'd be able to do it.
Look in the yellow pages under welding. There are welding shops everywhere and those guys are usually the real pro's owner operators in small shops sometimes equal small bills also. Or yahoo local.
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Old 09-20-10, 06:13 PM   #17
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Look around till you see someone with an acet/oxy rig. Carry your frame up to them, after you clean up the weld area with sandpaper. Get it down to bare metal. Ask if they will braze it for you. Look wistful. Or go to the local high school and ask the shop or the Ag teacher to get a kid to do it.
It's really a minor repair. The hard part will be prepping the metal for the weld.
Get it prepped then find some gearhead in a garage to stick it together for you and buy them a quart of beer.
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Old 09-20-10, 06:34 PM   #18
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Contact your local bike club and see if there is a local frame builder they can recommend. He (or she) will be able to do this repair easily and will be able to evaluate if the rest of the frame is in good enough shape to be worth doing anything with.
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Old 09-20-10, 07:47 PM   #19
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Looking at the photos I would have to agree with some of the other posters that the frame is very rusted. I would also agree that the frame isn't worth welding. And by the looks of the first pic, howbeit it is very fuzzy, that it appears the other side of the brake bridge is also bad. It does appear that someone tried to spread the stays and failed. Welding this bridge back will only buy you time for something else to break like the other side of the brake bridge, and you may pay more for the weld job then what you paid for the bike, and then have to turn around later and do more welding. I would stop the money leak while you can. Strip the parts off the bike, and either sell them on E-Bay to try to recoup some of the money, or keep the parts for another frame.
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Old 09-20-10, 07:50 PM   #20
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Contact your local bike club and see if there is a local frame builder they can recommend. He (or she) will be able to do this repair easily and will be able to evaluate if the rest of the frame is in good enough shape to be worth doing anything with.
Looks like we have covered the entire spectrum from fixing it with JB Weld to consulting a professional framebuilder.

Seeing how you bought it for $40 I would think the frame is in good enough condition to use. You've already judged it to be sound.
The hardest thing about a job like that is getting it ready to braze. Get some sandpaper or an angle grinder with a brush and strip the frame down to bare metal in the area to be repaired. Find someone with a torch and show them the prepped frame and ask them if they'll braze it for you. If you have the prep work done then someone would probably do the brazing for little or nothing. Ask around.

My everyday ride, a Trek 820 has rust spots that look as bad as the ones in your picture and I don't think twice about riding it. You can tell if the frame is unsound.

Last edited by sknhgy; 09-20-10 at 08:06 PM.
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Old 09-21-10, 07:24 AM   #21
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You've already judged it to be sound.
Considering the OP wanted to "glue" this broken joint back together, I'm not sure his judgment on the soundness of the rest of the frame is to be trusted.
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Old 09-21-10, 10:12 AM   #22
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A thought popped into my mind. The frame could be broken at this point due to some type of trauma. Maybe it got hit by a car while stored in the garage. If so, there could be other things wrong with it. Perhaps you should at least have a reputable bike shop mechanic have a look at it.

I know this goes against what I've been saying, but hey, only fools and mules never change their mind.
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Old 09-21-10, 11:06 AM   #23
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Considering the OP wanted to "glue" this broken joint back together, I'm not sure his judgment on the soundness of the rest of the frame is to be trusted.
I bet he glues it then sells it on E-Bay again or Craigslist.
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Old 09-21-10, 12:36 PM   #24
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Records were hi-ten steel, weren't they?
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Old 09-21-10, 02:53 PM   #25
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If this frame was brought to our shop we could have it fixed pretty quickly... if the rest of the frame was sound.

This is why, if you decide to have it fixed, need to see someone who can make that assessment before they repair it.

It would cost you as much to have it fixed as you paid for the frame as besides the actual repair there will be some set up and prep that needs to be done so you will be paying for about an hour of someone's time.

The frame looks like it needs more than just a repair as the finish looks pretty rough.
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