Can this be silver brazed or must be welded?

[bobswire]

I noticed what looked like the paint was cracked hoping it was not a crack in the tube but it is. Looks like the metal is split at the junction where the seat tube and stay meet and continues to up to the top. Is this repairable by silver brazing (which I can do myself) or must it be welded ?

http://oi46.tinypic.com/rmqoly.jpg

Looking at it from the inside.

http://oi45.tinypic.com/2z3qkie.jpg

This if from a vintage Jeffrey Richman frame I've been using as my all rounder.

http://i46.tinypic.com/1zdx3if.jpg

http://i48.tinypic.com/qznimx.jpg

[TopQuark]

Should be an easy fix if it is steel.

[ultraman6970]

Thats steel, yes it can be brazed back the issue is if it worth the money and time to get it fixed, the frame doesnt look like having a super good resell value even in good condition (maybe im wrong). Personally if you dont have a sentimental attachment to that frame I would advice you to find another one.

If you want a ****ty repair that can be tigged fairly quick and cheap, how long it will last??? who knows. If you want that brazed really well it will cost you more than what the frame worth maybe.

[monkeybanana86]

In light of what ultraman says if you want it done cheap and if you can braze even a little an option would be to see if tech shop in Menlo or another shop (there's one in Oakland I forget the name) will let you use their torch or maybe someone hanging out there could help you. Just fill it in then go to a shop with a reamer. I'll pm you some repair guys if you don't want diy.

[JLP]

I'm curious what the professional frame builders will say. Nice looking bike.

I think this is not so straightforward.

Here is a wild guess.

Drill a small hole at the bottom of the crack to stop it from propagating any further.

Clean it all back to bare metal

Add a brass fillet over the crack from stay to seat binder without detaching stay or stay cap. Pull some brass through the crack to the inside.

Clean and ream.

What say you professionals?

[bobswire]

Thats steel, yes it can be brazed back the issue is if it worth the money and time to get it fixed, the frame doesnt look like having a super good resell value even in good condition (maybe im wrong). Personally if you dont have a sentimental attachment to that frame I would advice you to find another one.

If you want a ****ty repair that can be tigged fairly quick and cheap, how long it will last??? who knows. If you want that brazed really well it will cost you more than what the frame worth maybe.

Actually this frame is pretty unique and a one off built for and by Jeffrey Richman,another of the early N.Cali frame builders along with likes of Ritchey, Breezer et al.
http://www.sonic.net/~ckelly/Seekay/artofmountainbike.htm

[JLP]

Actually this frame is pretty unique and a one off built for and by Jeffrey Richman,another of the early N.Cali frame builders along with likes of Ritchey, Breezer et al.
http://www.sonic.net/~ckelly/Seekay/artofmountainbike.htm

Yeah, this is something you want to save, for sure.

[guyintense]

Or you could forget the clamp and use a quill type seatpost, sometimes referred to as a frame saver.

[David Kirk]

If I'm understanding the photo properly I think fixing this effectively could be tough.

First - you can't have it tig welded. The stays are mounted to the seat tube with either silver or brass and this would all need to be 100% removed so that you could get a clean weld.

So any repair will be a brazed affair.

The problem is that the s-stay is ripping a chunk of seat tube out/off the seat tube which will, when it finally goes, will leave a hole in the side of the tube. So it's the seat tube itself that is the issue.

One could put a much larger fillet on the s-stay where it meets the seat tube and that may work but it's hard to say. I think this would be your best bet. This repair will of course cook the paint so it will need to be redone.

Again - If i understand this correctly - the seat tube is on it's way out. It looks as if this may have been caused by using a seat tube that was too thin to begin with.

Not the best news I know but that's what it looks like from here.

Dave

[bobswire]

If I'm understanding the photo properly I think fixing this effectively could be tough.

First - you can't have it tig welded. The stays are mounted to the seat tube with either silver or brass and this would all need to be 100% removed so that you could get a clean weld.

So any repair will be a brazed affair.

The problem is that the s-stay is ripping a chunk of seat tube out/off the seat tube which will, when it finally goes, will leave a hole in the side of the tube. So it's the seat tube itself that is the issue.

One could put a much larger fillet on the s-stay where it meets the seat tube and that may work but it's hard to say. I think this would be your best bet. This repair will of course cook the paint so it will need to be redone.

Again - If i understand this correctly - the seat tube is on it's way out. It looks as if this may have been caused by using a seat tube that was too thin to begin with.

Not the best news I know but that's what it looks like from here.

Dave

Thanks Dave, I'm going to give a shot at brazing it myself first. The paint is no problem since I painted it. I'll update my progress with pics.
BTW I done a lot copper pipe brazing when I was in construction and still have the tools.
-Bob

[Louis]

Aren't seat stays nearly always in compression? If so, I'm having a hard time understanding how that happened due to the stay. You would think that the stay pushes up against the top of the ST which in turn pushes against the seat post. Although I suppose the SS does pull the ST wall up and forward, which would result in some tension in that area. I'm just not sure how much.

I'm not 100% sure I understand the pictures, but another possibility is that the failure occurred due to seat-post clamping loads at the binder, pulling the ST wall toward the ST centerline.

Bob, good luck with the repair.

Louis

[bobswire]

Aren't seat stays nearly always in compression? If so, I'm having a hard time understanding how that happened due to the stay. You would think that the stay pushes up against the top of the ST which in turn pushes against the seat post. Although I suppose the SS does pull the ST wall up and forward, which would result in some tension in that area. I'm just not sure how much.

I'm not 100% sure I understand the pictures, but another possibility is that the failure occurred due to seat-post clamping loads at the binder, pulling the ST wall toward the ST centerline.

Bob, good luck with the repair.

Louis

That would have been my guess but it takes a 27.2 post that is very tight,thus takes very little torque to tighten in down.
Maybe the guy who had it before me used a smaller post and torqued it too much to get it to hold?
I believe it was there when I first purchased the frame but it wasn't all the way through as it is now. I thought at the time is was just a hairline crack in the paint.

[ultraman6970]

I dont think is a problem with the bike being used with a smaller seatpost diameter, a lot of bikes moving around and never failed, personally 1st time i see one that cracked in that area, really rare.

IMO it failed because of the design, The guy just fillet the stuff up and fillet the clamp in there, then filed around before putting the stays, with the years the tubing just gave up, so basically is the seat tube naked and pretty much that end is thinner than the bottom, it just gave up because was not designed to work like if it was a lug. Or the builder just cut a lug (based in the perfection of the pieces) and used only the back of it, add to that what i said before and the thing cracked just at the limit between the lug (the half of it) and the seat tube, that's why it cracked in straight line.

How to fix it... drill a small hole at one end, and use a dremel to just make like a 1mm to 2 mm straight line over the crack, Then braze over it, is not hard if you know what are you doing, neither takes that long, maybe 30 mins maybe less.

File that big time out side and from the inside, personally whatever reamer used will need to be resharped because the bronze is harder than the steel and the blades are not made for bronze. I would use a dremel drum to leave it as flat as possible and then I would ream it just because what I said before.

Primer, paint, clear... done.

[JLP]

whatever reamer used will need to be resharped because the bronze is harder than the steel and the blades are not made for bronze.



Really?

[ultraman6970]

The problem I have is finding the words for it.... maybe the word is not harder... hmm... either way... is fixable, hope you can find somebody that can braze that.

[bobswire]

The problem I have is finding the words for it.... maybe the word is not harder... hmm... either way... is fixable, hope you can find somebody that can braze that.

Yeah,"me",pretty much like you suggested.

[rwsaunders]

Thanks Dave, I'm going to give a shot at brazing it myself first. The paint is no problem since I painted it. I'll update my progress with pics.
BTW I done a lot copper pipe brazing when I was in construction and still have the tools.
-Bob

Bob the Plumber, yes he can!:cool:

[guyintense]

BTW I done a lot copper pipe brazing when I was in construction and still have the tools.
-Bob

What kind of construction did you do where you brazed copper pipe together?

[bobswire]

What kind of construction did you do where you brazed copper pipe together?

This kind.

http://www.youtube.com/watch?v=07ODV2Bdqow

[David Kirk]

In looking at the photos again I think I was wrong. I thought that the seat stay was ripping off the side of the seat tube but now I see that it's the binder that is tearing the seat tube at the end of its fillet.

This is most likely due to the seat tube being too thin, distorting with the heat and then being reamed round after the fact and making the wall of the ST very thin at the highly stressed area.

If I have it right (this time!) getting a good repair will be really tough. You can add more brass to it but the brass has a tensile strength similar to butter and can lend little to the structure. It would be like gluing two pieces of wood together, having the joint fail and then in an effort to repair it smearing more glue on the outside. It doesn't need more glue it needs more wood.

It can't hurt to drop more stuff on there but I wouldn't get your hopes up. I've fixed stuff like this a very long time ago (20 years?!) by silver brazing a sleeve into the frame and then reaming it out to fit a smaller post. You'd need to braze in the sleeve, clean it up, slot it, and repaint it. It can be done but it's a bit of a b!tch.

dave

[Tyler Evans]

File off the current binder and put on a seat clamp of the appropriate diameter (maybe prime the exposed bare metal if you are so inclined). It will put the cracked part under compression to halt crack propagation. It will be functional if that is what you are after.

[David Kirk]

File off the current binder and put on a seat clamp of the appropriate diameter (maybe prime the exposed bare metal if you are so inclined). It will put the cracked part under compression to halt crack propagation. It will be functional if that is what you are after.

I was thinking the same thing but it didn't look like there was enough seat tube material up above where the seat stay mounts on the side of the ST. It looks like 2mm of so. What do you think?

dave

[dvancleve]

What about silver brazing a piece of tubing into the seat tube, 4" or so (whatever is considered adequate to support the seatpost) then reaming it to fit a smaller diameter seatpost, say 26.4mm? No clue if something like that would work or if it is feasible, just a thought...

Doug

[ultraman6970]

Thats what david kirk was saying... like that idea but for that the guy has to really handle the torch.

[guyintense]

This kind.

http://www.youtube.com/watch?v=07ODV2Bdqow

OK but how does that compare to fillet brazing a bike frame?

[ultraman6970]

The cooper and the material they use to braze cooper is not even close to what you use in a bike, the melting temperatures are different so what it can take you to do in 5 mins in cooper can take you like an hour if you are going to use those home torches.

Is not that cant be done the issue is that after an hour trying to get the right temperature you are better renting an oxy acetylene torch, because that torch is more precise to heat the steel than a little one.

[Tyler Evans]

I was thinking the same thing but it didn't look like there was enough seat tube material up above where the seat stay mounts on the side of the ST. It looks like 2mm of so. What do you think?

dave

I totally agree. I was so focused on the binder and the internal crack that I didn't see the forest for the trees. I think the best thing for the OP to do is to repair it in the most manly way he sees fit and keep us posted.

[dvancleve]

I guess I didn't read all of Dave's post... At least I was on the right track :D

Doug

Thats what david kirk was saying... like that idea but for that the guy has to really handle the torch.

[Louis]

silver brazing a sleeve into the frame and then reaming it out to fit a smaller post. You'd need to braze in the sleeve, clean it up, slot it, and repaint it. It can be done but it's a bit of a b!tch.

This sounds like the best option to me - and the most likely to last. I don't think the braze material alone would be a very good load path, but putting a sleeve in there should help a lot.

[Chance]

Aren't seat stays nearly always in compression? If so, I'm having a hard time understanding how that happened due to the stay. You would think that the stay pushes up against the top of the ST which in turn pushes against the seat post. Although I suppose the SS does pull the ST wall up and forward, which would result in some tension in that area. I'm just not sure how much.

I'm not 100% sure I understand the pictures, but another possibility is that the failure occurred due to seat-post clamping loads at the binder, pulling the ST wall toward the ST centerline.

Bob, good luck with the repair.

Louis

My guess is that it's a combination of the two loads highlighted. If post was over-tightened it would place the seat tube in circumferential tension. Then seat stay loads would add to that stress near the bottom where the seat stay first makes contact with the seat tube (at an angle but still cumulative). As you move up the joint SS stresses should gradually reduce. Notice the crack seems pretty wide at bottom and there may even be a little discoloration of the inner tube surface where seat post moved relative to seat post. In any case the crack doesn’t extend to upper edge which suggest it wasn’t caused purely by post over-tightening.

By the way, seat stays are not always in compression. Likely not the problem here though.