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Ive recently adopted a tame tig welder who has all the skills required to do my repair for me.
But he doesnt want to use the wrong rods.
Anybody know what spec rod is best for these frames?
Ta
Without wishing to sound like a complete nay sayer, surely the one to ask would be the welder with all the skills? If they're not sure which to use I'd guess they're lacking at least one of the skills required and I'm not sure I'd be happy letting them loose on ti. It's not like it's renowned for being easily worked & repaired or forgiving of welding errors.
This. Ti frames are notorious for giving people that work with them all day a hard time.
Don't let someone learn to weld Ti on your frame.
Don’t let someone learn to weld Ti on your frame.
This^
Been there,done that.
Save up and send it to somewhere like Enigma
Can't help you with the rod spec but having been a coded welder for a time I'd also not be able to tell you what to use. If someone handed me a frame and asked to weld it I'd ask what's it made out of, simply saying titanium wouldn't be enough and there's no way I'd be able to tell from looking at it. As for the practical skills of the actual welding it shouldn't be a problem imo, though I haven't seen the crack.
I’d ask what’s it made out of
The significant difference here though is that's not the question. The op's tame welder isn't asking for info to make his decision from, he's asking how to do it.
I'd expect a sparky to ask what i intend to run off a new install, i wouldn't expect him to ask me what cable they should use.
Commercially pure filler wire
No. Different filler material for different alloys, so yes you need to know what the frame is made from before selecting a rod.
"The significant difference here though is that’s not the question. The op’s tame welder isn’t asking for info to make his decision from, he’s asking how to do it."
Well, not quite- rather than asking for the info to make the decision on what rods to use, he's asking for the answer, that could amount to the same thing- it doesn't necessarily mean he can't take the info and come to the same answer.
I can tig weld but am no pro. Not event a bit of a pro; but I can weld aluminium and steel well enough. I thought Ti welding needed a purge chamber. Or is that just best practice? Does your man have such a thing?
95% of Ti Frames are made from Ti Grade 9 which is 3% Aluminium and 2.5% Vanadium.
You need a shielding gas, but that's not the worst part. Ti has dramatic thermal cooling effects which create substantial compressive stress when allowed to cool quickly. Ideally, you'd want the area being worked to be both shielded and at 600deg before you started welding. You'd then allow for a gradual cooldown over time until the part is below 300deg. At this point you can allow it to air cool without stress or oxidisation.
If you struggle to get Grade 9 rods, Grade 5 can be used (it's the same composition, but in different quantities), but the weld zone will be stiffer than that tubes, though that would be the case anyway.
Afaik the issue with Ti frames is that yo can't let anything contact the weld until it's cooled, hence running positive pressure inert gas inside the frame. The gas sheath from the TIG completes the isolation. The rest of the issue is that people who can weld other materials perfectly well can fail at Ti and produce bad results.
As an ex-printer I'm totally fine with the idea of time served crafts, but just like my experience of silver halides doesn't necessarily guarantee I'll produce excellent (or even successful) Platinotypes, an excellent and well qualified welder isn't necessarily going to be any good with Ti bikes unless they've got form in the field to point at.
You could always argue that a broken frame is a broken frame regardless until it's fixed, but while I'd be happy letting a time served TIG welder loose on a regular steel frame if I had a broken Ti frame to repair I'd be finding someone that had a success record of Ti frames.
I'd want to be sure that the welder was happy with thin materials before being concerned if he knows how to weld Ti. With the correct filler and adequate shielding (including back-side), if he's not competent with very thin wall, your crack will become a big hole very quickly.
I think those were 0.9mm main tubes.
He is an extremely good welder, i am in no doubt he can do the job just fine...
But it is impossible for him to do the job correctly without knowing what material he is welding.
There are a massive number of titanium alloys out there and as many rods to match the material.
Maybe my question should have been does anybody know what the spec is of the downtube on a Ti On-One Inbred?
I should add, i have been a structural welder for 20 years so i sort of know what i am on about....but not when it comes to TIG work.
Brant. I would say they are quite a bit thinner than that.
Cheers Daffy....i shall try and get some grade 9 rods from the supplier
why cant you ask on one what alloy it is?
I used to work with welders making ti hubs for peugeot rally cars- I dont recall them using any special cooling process
Helium gas shield is not difficult to set up, but I know that fillers for steel wont work
I weld ti in a vacuum chamber. No filler used but I let stuff cool over 20 mins or so before venting chamber. Cleanliness is everything.
>Brant. I would say they are quite a bit thinner than that.
Well, I've never seen thinner than 0.9mm used as a PG tube in a Ti frame.
It's 3/2.5 Ti, yes.
>why cant you ask on one what alloy it is?
It was launched in 2002. There's only me on the planet who knows anything about it, and apparently I have got the wall thickness wrong.
http://www.singletrackworld.com:80/article.php?sid=81 1"> http://web.archive.org/web/20030401174324/http://www.singletrackworld.com:80/article.php?sid=811
why cant you ask on one what alloy it is?
I suspect they won't even know which factory it was made in 😉
>I suspect they won’t even know which factory it was made in
ORA.
that's cheating. you're not on-one 🙂
Grade 2 cp filler rods are 172 quid a kilo
grade 5 eli which is certified is 850 quid per 5kg min basically the cheapest way to get it is this route and then sell it to your friends as lightweight coathangers
Grade 9 is very uncommon as wire ie not stock on the shelf as coil even to be drawn down to wire straightened then cut
however i have seen some folks selling single cp2 1000mm long wires for 6.89 each
^^^^^^^ this is from a supplier i use in the UK ^^^^^^^^
framebuildery types also use this guy if they dont know where to source domestically
https://www.titaniumjoe.com/index.cfm/products/weld-wire/
Hello Mike. Give us a ring sometime.
I follow 44 bikes on insta, I doubt I'll ever be able to buy one but the welds....
Bead widths look a bit variable on that instagram link tbh
3Al/25V thats all i needed to know..thanks Brant..I wasn't saying the tube isn't 0.9mm, but it appears thinner.....optical illusion probably!!!
mickmcd Which rods would be best for this material?
Brant - whilst you are answering questions, I've the 1/2 EBB 456 prototype, was there a 2/2?
Always bugged me that.