Craked steel frame (photo)
 

Hi,

I recently bought a used On-one inbred 29er on ebay that was supposed to have a scratch on the top tube badly covered by messy paint. On closer inspection, and after peeling off some paint, the frame has a 15cm *crack* on the side of the top tube. The tube wall gives in with minimal force from my thumb. Is this wealdable in a trustworthy way? How about cost? The frame is DN6 cromoly steel.

http://i27.tinypic.com/1zmp15j.jpg

BTW the ebay seller's ID seller is easterpark so beware. He told me he had broken a leg or arm riding just after the transaction and that makes me believe in Karma. I am also really bummed as after several upgrades I am broke and with no bike to ride.

Tiago

did you contact paypal? you should be pursuing the seller thoroughly. if you get your money back, you won't have to worry about fixing it.

I bought it over two months ago and only today discovered that the scratch was indeed a crack. I was away for 5 weeks and before leaving gave this this guy a positive feedback:notamused:.
There are other horror stories about this bike such as missing the on-one proprietary "canti-bosses" and having a threaded fork on a threadless setup, and the headset had a mixture of threaded threadless parts :eek:

How about welding?

That "crack" is oddly straight as an arrow. Looks like cheapo seamed tubing to me. You might want to talk to On-One as well. Maybe a bogus tube set?

Go ahead and have it welded. Problem is, maybe you should save that money and try again?

Welding thin-walled tubing is tricky business even for the experienced. It'd be very easy to burn through getting the seam going. Even if it's successful at first the seam will shrink as it cools, adding stress to the material and maybe even warping the frame.
One repair that I''ve been curious to try for some time is to sand the tube down to bare metal and then wrap some CF tape + epoxy around it as a splint. Done correctly I can't see any scenario where the frame would fail unexpectedly while JRA after such a repair, and I'd be willing to ride it.
Barring that I'd try to find another tube with a matching diameter, cut a suitably overlapping patch out of it and braze it over the crack with a nice low-temp solder with good capillary action. Silver comes to mind.

I wonder if an old fashioned brazing wouldn't be better than welding in this case because the tube walls are reported to be so thin?

Statute of limitations is 90 days. You still have options to persue rememdy

A competent welder should be able to fix that. Its a straight line so even a welder with not so great tig skills can fix that seam.

Or since its steel, you can just braze a line of brass down the seam then sand clean.

Either option, you'll wreck your paint

Well, I can't vouch for this particular frame, but I've built stuff out of cut down bike frames several times and it can be quite challenging. Conduit pipe is a dream to work with in comparison.

You can:

1. Contact the seller and paypal about a refund as the goods were not as represented.

2. Try to have the frame crack brazed and repainted there by throwing good money after bad.

3. Suck it up and accept you were cheated and take the loss as a lesson in human nature. You now have an interesting art item to hang on your wall.

Thanks for the advice on welding/brazing and ebay.

The main thing is that the freaking bike didn't break while I was riding it. And I am very grateful about with my general state of good health.

Regarding ebay, I didn't know that I could still ask for a refund after giving positive feedback, so I will look into that. I have just emailed the seller just to make the point that I am ingood health but bad things could have happend.

Failing this I might ask the advice of local welders but I am now unsure of the reliability of the repaired frame. As tradtimbo pointed out this could be a crack along the welded seam of cheap(er) chromoly. The On-one website is ambiguous about this:

"We use different profiles of DN6 depending on the frame. The Inbred uses the lightest grade, the Gimp a custom drawn grade for dirt jumping, and the Runt uses a super-strong straight-gauge format for BMX abuse."

When I asked On-one "is the tubbing seamed or drawn?" I still got an ambiguous answer:

> the Inbreds are now custom DN6 double
> butted 4130 chromoly steel tubing
> that part of the website is really old.. the Gimp and Runt
> are dead....

Mine is an older (2005?) bike with the sliding dropouts, but I don't even know if the new ones are drawn or seamed. Is a Kona Unit 2-9 made from drarwn chromoly tubbing or are cheaper frames all the same?

Humm... at least on ebay.co.uk there is a time limit of 45 days after the payment to open a case in the resolution center. Looks like it will only be a matter of bad conscience for seller.

There's nothing "old fashsioned" about brazing, but yes I tend to agree it might be better. Bottom line, I would definitely take it to a framebuilder for a determination instead of just any old brazer/welder. Those tubes are quite thin.

yeah but your creditcard company is usually 90 days. but I guess if you just used paypal funds, its 45 days.

If you look down the inside of the seat tube with a flashlight, you might be able to see a seam...

I don't know anything about welding or metallurgy, etc, but it doesn't seem at all possible for seamless tubing to crack in such a nice straight line.

Am I the only one that thinks duct tape can fix it...?:innocent:

I don't think you're allowed to ride an "InBred" unless you're from Kentucky. :)

"Seamless" rated tube can still have seams, trust me. Your tube should be able to be welded by a competant craftsman. I would stress relieve (post weld heat treat), since this is a significant crack right on the joint seam...may even consider replacement of that tube with material of known parentage.
Keep us posted, good luck!

Yeah, seamless tubing actually starts out the same as seamed tubing. It's made from flat-sheets which is rolled and welded into seamed tubing. To make "seamless tubing" from that, a mandrel is inserted and rolled again to even out the seam. I suspect in this case that the tubing wasn't seamless with the extra rolling step, which forges and strengthens the seam.

Laying a bead of brass via brazing would work fine. But I would worry about the seams on the tubing giving out in other areas.

You are wrong according to Tim Paterek. Seamless tubing begins with a solid steel rod. It is heated to red hot and pierced lengthwise to form a crude tube.

Thanks for the continued input,

I peered inside the seat tube using a flashlight as suggested and couldn't see any seam. So at least that tube IS seamless. I have contacted a framebuilder across the country that gave me two options:
- replace the top tube and repaint for 140 GBP (224 USD)
- braze a thin section of tubing over the crack for 30 GBP (48 USD)
Mailing should be 15 to 20 GBP.

I feel bad about just binning a frame but since a new identical frame costs 160 GBP mailed to me I will have to think about the options.Hopefully a custom paint job would be better than the poor On-one factory paint.

Tiago

There are two types of "seamless", butted or straight gauge bike tubing.

The highest quality (and price) tubing is truly seamless and made by starting with a solid piece of round stock that is pierced lengthwise and then passed over a series of mandrels and through dies to achieve the desired diameter and wall thickness(es).

Lower cost steel tubing is made by rolling a piece of flat stock over a form and welding the edges together. The resulting tube is then passed over mandrels and through dies that form the final shape and, if done right, make the seam almost undetectable. The OP's inability to see a seam inside his frame doesn't mean the tubing is truly seamless and the fact it split lengthwise suggests otherwise.

BTW, the fold and weld technique is also used for some very expensive exotic materials that aren't available in rounds or tubing of the right size or are too difficult to work. Early 6/4 Ti frames were made this way since 6/4 tubing wasn't available.

True seamless tubing starts as a solid ingot that is pierced by a mandrel while hot and soft. It is then drawn through a series of dies to the final diameter and wall thickness. At no point is it rolled and welded. C.f. Reynolds own description of the process from their "Top Tubes" brochure.

Some relatively modern tubes (Reynolds 501, True Temper, Columbus Aelle, etc.) start out as seamed tubes in the manner you describe, and are subsequently drawn through dies to achieve the final dimensions and obliterate the seam, but these are not true seamless tubes.

The OP's frame appears to be made from inexpensive seamed tubing, which is not mandrel-drawn and thus more prone to separation at the seam.

If you're concerned about appearance, replace the tube. Otherwise, the patch will work fine.

My recommendation is to get the new frame. The cost of the repairs, repainting plus shipping will total a large fraction of the cost of a new one and you will know the frame's history.

The one you bought has obviously been damaged and/or abused. The original seller certainly knew something serious had happened to it or he wouldn't have misrepresented it on e-bay. Cut your losses and replace it.