Jockie

I found two cracks in a second-hand Lynskey Cooper I just acquired on an online auction.
(Cracks were not mentioned in the listing!)
Larger crack is on the outside of the DS chainstay and smaller one is on the underside of the NDS chainstay.
Do these look repairable to framebuilders?
Sending back to Tennessee is going to be expensive from here. There is a local who appears to have experience repairing titanium bicycle frames.

Cynikal 

Return to seller and get refund

Jockie

Unfortunately, that is not possible.

unterhausen

I am wondering if those are just defective chainstays. Welding would probably work. I'm not sure I could trust it though

GrayJay

Strange looking cracks. If this were a stress crack from use/fatigue then it would more likely run radial around the tube, instead of along the tube axis length. Might be that the seatstay tubing was formed from sheets that were then welded into a tube along a seam and that is what is now re-cracking? Given that the seatstays stress is mostly in compression, the direction of the crack probably does not greatly affect the strength of the seatstay. Laying down a TIG bead along the crack and then grinding smooth would likely be worth trying.

unterhausen

That's what I was thinking, they are welded tubing that was drawn after welding. Which I think is how it works. That would explain the somewhat random cracking. Although the crack would probably veer back and forth from one edge of the heat affected zone to the other. It's not the first time I have seen cracking like this.

Kabuto

Online auction means Yahoo Japan auctions (or Mercari)? If so, its a bit of a hassle to sort out but you can definitely return the frame even if the listing stated "no returns". Especially so considering the cracks that weren't mentioned in the listing. Yahoo Japan (Mercari) will take your side on this one for sure.

guy153

Or there could have been some debris or imperfection in the die they were drawn through maybe? That would apply even if they were seamless. Idk how Ti tubes are usually made.

unterhausen

I don't know how Ti welded tubes are made, but the steel tubes I have seen that were drawn over a bad die just cracked in a straight line. I have never seen a picture of how the true temper tubing cracked in the early days, that would be interesting. Of course, steel tubes might also fail due to rust if they have a crease inside. Definitely pays to look inside your tubes before building. And measure seat tube internal diameters.

repechage

Ouch.

I take seller denies all.

Jockie

The seller claims that 'scratched and dirty' is an accurate description.
The original manufacturer has suggested a repair would involve complete replacement of the chainstays.