Ti repair insight

[cgolvin]

This is, I think, aimed primarily at the skilled framebuilders who generously share their experience and insights with us.

This IF XS (https://www.ebay.com/itm/Independent-Fabrications-XS-Titanium-Carbon-Frameset/232723762433) came through my saved searches on eBay. The seller states that there are cracks in the ti chainstays:

"The titanium chainstays are cracked. Not due to neglect or crashing, but because the stays were likely formed to shape after they had been annealed, so the material was harder and when the stay shape was formed for tire clearance, it created too much stress at the 12:00 and 6:00 position.

Photos show the extent of the cracks. Both stays are cracked at the 6:00 position and the left stay is also cracked at the 12:00 position."

Lister is not the original owner so frame is not under warranty; I sent a note asking whether he had contacted IF to inquire about whether they even considered it reparable.

So, to ti experts: would it be foolish to buy this with the plan of having a skilled builder repair it? Mainly asking whether one would feel confident about the repair and the issue not resurfacing, but also cost of repair.

Thanks

[Bentley]

So do I understand that the stays were "shaped" after the tubes were annealed? I would guess this is mechanical crimping of the tubes to increase clearance? If so those tubes are toast but would not necessarily implicate the rest of the bike. I would assume the repair would be straight forward, but would recommend you find someone with this kind of experience.

[glepore]

Seller contacted IF and they said not repairable due to heat effecting the bonded joints.

[Bentley]

Seller contacted IF and they said not repairable due to heat effecting the bonded joints.

I did not realize that this is a carbon/Ti bike.

[zap]

Bigger question. What about all the other titanium frames IF produced using that type of chain stay tubing.

As alway's, inspect your bicycles regularly.

[David Tollefson]

So, to ti experts: would it be foolish to buy this with the plan of having a skilled builder repair it?

Not a ti expert, but I do play a mechanical engineer in my day job... Anyway, as stated in another reply, the carbon/ti bond is the problem, and the heat of any repair (the only repair of which I would accept would be chainstay replacements) would render the frame untrustworthy at best.

[bshell]

Carbon tube bonds aren't particularly close to area needing repair.

I'd say go for it if you really like it and can afford a little experiment. Plate patches at 6 and 12 or new chain stays.

[Mikej]

Wouldn’t touch it, as for the proximity of the weld to the carbon bond, I would think it’s too close for comfort.

[JWDR]

I saw this earlier today, before it had been bid on. For the right price I would just ride it till it fails. At its current $91, plus shipping it’s probably getting close to my maximum risk versus reward threshold.

[FriarQuade]

Couple of thoughts on repairing something like this. Replacing the entire chainstay is the best method of repair but the carbon bond makes that pretty much a no-go. You could however repair the existing tube. Stop drill the cracks, grind into the crack and weld them back up. The cracks are far enough away from the tube end that with a little care you can keep the bond from getting hot. The risk with this strategy is that it can fail again. As always the biggest problem with repairing titanium tube structures is getting the inside of the tube clean. Lord knows what got into that tube over the course of the frames life and that kind of contamination could make a weld repair fail down the road. This is why most if not all titanium repairs are done without warranty. But what do I know, I just make titanium hammers.

[numbskull]

I'm curious (and naive).

Why can't the carbon-Ti bond be separated then reassembled after the repair?
I'd expect it uses some sort of epoxy and aren't most epoxies heat sensitive with a melting point well below that of the resin in the carbon tube?

Barring this, is there some reason the lug/tube connection could not be submerged in a tank of water which would then act as a heat sink while the weld is made? This is (or was) a common technique for repairing lower unit skegs on outboard motors without needing to replace the rubber seals.

[Ed-B]

Isn't that shop the home of Black Mountain Cycles? Ebay ID and shop look familiar...

[David Kirk]

Never buy a broken bike.....there are just too many non-broken bikes to choose from.

dave

[Mark McM]

Whenever I buy a bike, the bike is never broke beforehand, but I'm always broke afterward. Am I doing it right?

[Black Dog]

Whenever I buy a bike, the bike is never broke beforehand, but I'm always broke afterward. Am I doing it right?

You got it. Always buy an unbroken bike. The bike should never be broke only the rider.

[Bentley]

Never buy a broken bike.....there are just too many non-broken bikes to choose from.

dave

This. Right answer

[cgolvin]

Never buy a broken bike.....there are just too many non-broken bikes to choose from.

dave

Thank you, Dave.
'Nuff said on this one.

[FriarQuade]

I'm curious (and naive).

Why can't the carbon-Ti bond be separated then reassembled after the repair?
I'd expect it uses some sort of epoxy and aren't most epoxies heat sensitive with a melting point well below that of the resin in the carbon tube?

Barring this, is there some reason the lug/tube connection could not be submerged in a tank of water which would then act as a heat sink while the weld is made? This is (or was) a common technique for repairing lower unit skegs on outboard motors without needing to replace the rubber seals.

You are thinking of bearing retaining compound, those are commonly heat sensitive. The 2 part epoxies that are used to bond composites together are ridiculously strong and are not coming apart without destroying something. I suppose you could cut the carbon seat tube out of the lug, ream out what's left, replace the chain stay and then replace the seat tube. But like Kirk said, there's plenty of not broken bikes to choose from.

[Pegoready]

The seller is none other that Mike at Black Mountain Cycles. Surprised he’d bother with that junk. At least the description is unequivocal about the frame being the basis of a $6000 wall hanger or stool project..

[unterhausen]

Never buy a broken bike.....there are just too many non-broken bikes to choose from.
I can't fix Ti, but I can fix steel, and I have thought about buying a fixer-upper a couple of times until I realized it would cost me the same as building a new frame. I suppose if the right broken bike showed up I might do it.

[zap]

The seller is none other that Mike at Black Mountain Cycles. Surprised he’d bother with that junk. At least the description is unequivocal about the frame being the basis of a $6000 wall hanger or stool project..

Best to take the fork off and sell that. The frame should be cut and sent off to the recycler. No point in having a potential legal battle.