# ti welds/discoloration bad?



## teamdicky (Jan 12, 2004)

Someone told me it was. Not pretending to know anything about it.

True?

How about this?


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## RCP FAB (Jun 15, 2011)

The simple version: Discoloration in TI is usually due to atmospheric contamination, assuming the base metal is clean. Ti is reactive to air as it is cooling, it must remain in the argon shield (both inside and out) until it has cooled. Removing the argon before it has cooled, or not using enough argon will cause the discolorations you see. Ti welds should be silver to light straw, inside and out.


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## Walt (Jan 23, 2004)

*Gah!*

I am far from a ti expert, but from what I've been told, that bike is probably unsafe. According to everyone I've ever spoken with: yellow/straw = ok. Blue/black = no go.

-Walt



teamdicky said:


> Someone told me it was. Not pretending to know anything about it.
> 
> True?
> 
> How about this?


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## RCP FAB (Jun 15, 2011)

That is a Triton frame, they use some pretty heavy wall Russian TI tubing. I've seen a bunch of trials guys beating on them pretty good and haven't heard of any failures. 

Not that I support his argument of "Don't worry about the colors"......


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## teamdicky (Jan 12, 2004)

I had some repair work done by some NASCAR welders. They just filed out the cracked weld and fixed it with an old ti seat rail (no argon).

I've heard some comments about the slight discoloration, and when I saw this I was surprised. I've had a Titus, a MOOTS, a DEAN, and a Thylacine... tiny stacks of dimes and no rainbows.


Just wondered what was going on there.


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## Walt (Jan 23, 2004)

*Keep in mind...*

The rainbows disappear if you brush or media blast (or hand polish) the frame, so unless you see it in it's "raw" state, you never really know what the original welds looked like. Almost all ti frames have some surface finishing done before they make it to the customer.

-Walt



teamdicky said:


> I had some repair work done by some NASCAR welders. They just filed out the cracked weld and fixed it with an old ti seat rail (no argon).
> 
> I've heard some comments about the slight discoloration, and when I saw this I was surprised. I've had a Titus, a MOOTS, a DEAN, and a Thylacine... tiny stacks of dimes and no rainbows.
> 
> Just wondered what was going on there.


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## teamdicky (Jan 12, 2004)

Walt said:


> The rainbows disappear if you brush or media blast (or hand polish) the frame, so unless you see it in it's "raw" state, you never really know what the original welds looked like. Almost all ti frames have some surface finishing done before they make it to the customer.
> 
> -Walt


Ahhh....

Well then, I just got to see the shiny coin piles. (except on another "repair" that was done).


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## RCP FAB (Jun 15, 2011)

It's pretty impossible (read: it is impossible) to tig weld any material with out gas, especially TI. Do you have pictures of what was repaired?


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## teamdicky (Jan 12, 2004)

RCP FAB said:


> It's pretty impossible (read: it is impossible) to tig weld any material with out gas, especially TI. Do you have pictures of what was repaired?


It would be hard to get photos. It was repaired at the weld where the TT meets the DT at the HT. I've never been able to get a good shot of it.


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## smudge (Jan 12, 2004)

yo, that color is no good. No good at all.

Also RE finishing before the frames go out...yes, they get finished, either by media blasting or by scotchbrite usually but you can't remove color like that with the grade beads that Moots, Eriksen and Potts use on their bikes...not that they'd need to...there's only a slight golden hue to the haz if any color at all. You can't remove that level of color with a typical scotchbrite hand pad either without leaving blood on the frame. Point being that with the good builders those colors aren't evident anywhere inside or outside the frame once the welding is finished.

edit: also, this is a good resource - check the color chart at the bottom Miller - Titanium 101: Best TIG (GTA) Welding Practices


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## kampgnar (Apr 13, 2007)

Rody does a great job explaining some of the Ti process and considerations here.

This has some good information as well.


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## Cracked Headtube (Apr 16, 2006)

I've never tried Ti. It is beyond my efforts at the moment. I've found this thread informative thus far. Eric Baar of Ground Up Designs does alot in the way of Ti. 

Is Titanium ever butted?


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## tburger (Apr 27, 2004)

teamdicky said:


> Someone told me it was. Not pretending to know anything about it.
> 
> True?
> 
> How about this?


Maybe he wanted that coloration for effect? 

Either way, here's a pic of Potts in the process of welding the seat stay bridge on my frame. You can see the coloration around the welds in that area.


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## smudge (Jan 12, 2004)

Cracked Headtube said:


> I've never tried Ti. It is beyond my efforts at the moment. I've found this thread informative thus far. Eric Baar of Ground Up Designs does alot in the way of Ti.
> 
> Is Titanium ever butted?


Yes. Reynolds supposedly offers drawn butted tubing. Feather tech offers center less ground tubing. Seven has a lathe set up specifically to butt tubing.


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## j-ro (Feb 21, 2009)

smudge said:


> Yes. Reynolds supposedly offers drawn butted tubing. Feather tech offers center less ground tubing. Seven has a lathe set up specifically to butt tubing.


So Sean, are they removing material from the outside or the inside of the tube.

Seems like the chance of overcutting an area are pretty high. I mean, you're not dealing with a very thick tube to begin with right?


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## teamdicky (Jan 12, 2004)

tburger said:


> Maybe he wanted that coloration for effect?
> 
> Either way, here's a pic of Potts in the process of welding the seat stay bridge on my frame. You can see the coloration around the welds in that area.


Did he snap that photo with his tongue?


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## tburger (Apr 27, 2004)

teamdicky said:


> Did he snap that photo with his tongue?


Haha. No, I took the pic. I got to hover over his shoulder for a bit while he welded. Pretty cool! It's all in the Potts thread I started on the 29er forum.


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## Triton Bikes (Jan 6, 2010)

RCP FAB said:


> That is a Triton frame, they use some pretty heavy wall Russian TI tubing. I've seen a bunch of trials guys beating on them pretty good and haven't heard of any failures.


Thanks!
That would basically be my answer.

Too many Triton trials frames living 5 times longer than the aluminum ones speak for themselves.

Meanwhile I am working on this issue to make everyone happy.
And I would like to thank smudge on his advisory on weld shielding!

The frames we build are strong, the walls are thick, the warranty is still there and it works.

I have had a few breakage issues. Most were already out of warranty but we still fixed the frames for free. I think I had one frame that cracked within a trials warranty - a year. Oh, and a BMX frame too. Others took 2-5 years of abuse before breaking. All of them were trials frames. Half of those frames cracked on the weld and another half cracked in the middle of a tube or like 100mm from the headtube.
All of these frames are still being ridden after being fixed.


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## Rody (Sep 10, 2005)

Sir Dicky, 

Here is a close up of a still steaming Ti weld...bright and shiny. Most of any color you see is reflection from the window above the table.

Although a contaminated ti weld, like above in the original post, will survive for a while, when you see white/chalky residue the game is over, can't even grind that mess out and fix it. 

cheers,

rody


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## mitzikatzi (Sep 9, 2008)

Some time oh Google finds PORTABLE HARDNESS TEST TECHNOLOGY FOR ASSESSING TITANIUM WELD
QUALITY



> Weld colors indicate that inert gas shielding during welding was somehow compromised. It is well
> understood that weld color(1) indicates that oxidation has occurred. Weld color cannot be used to
> determine whether the weld pool was contaminated. During out of chamber welding, weld color can
> often be related to disturbances in trail shielding, which only affect the surface. This is because titanium
> ...


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## smudge (Jan 12, 2004)

mitzikatzi said:


> Some time oh Google finds PORTABLE HARDNESS TEST TECHNOLOGY FOR ASSESSING TITANIUM WELD
> QUALITY


Interesting, but keep in mind the context of the discussion. That paper is about a different material (Grade 2 or Commercially Pure), of a much different thickness (pipe, vs. tubing), and a vastly different use (hydraulic vs. structural).


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## 29ger (Jan 1, 2011)

The reason that titanium discolors, as mentioned is exposure to the atmosphere (i.e. not properly shielded with Argon) while hot. This is a problem because the titanium will absorb the contamination, form oxides and nitrides, and become brittle if contaminated enough.

As for your specific photo, some industrial standards accept blue discoloration, and some reject it depending on how critical the weld is. So while some of the other straw colored welds shown in this thread were welded with superior shielding, the weld in question still has the potential to be ok (or not ok depending on your interpretation of blue coloring). There are several color charts for titanium weld acceptability if you search the internet.


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## bee (Apr 7, 2008)

Rody said:


> Sir Dicky,
> 
> Here is a close up of a still steaming Ti weld...bright and shiny. Most of any color you see is reflection from the window above the table.
> 
> ...


If this is a Triton weld, that is MUCH better than what they've been doing before in that first picture. Maybe their processes have improved.


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## edoz (Jan 16, 2004)

29ger said:


> The reason that titanium discolors, as mentioned is exposure to the atmosphere (i.e. not properly shielded with Argon) while hot. This is a problem because the titanium will absorb the contamination, form oxides and nitrides, and become brittle if contaminated enough.
> 
> As for your specific photo, some industrial standards accept blue discoloration, and some reject it depending on how critical the weld is. So while some of the other straw colored welds shown in this thread were welded with superior shielding, the weld in question still has the potential to be ok (or not ok depending on your interpretation of blue coloring). There are several color charts for titanium weld acceptability if you search the internet.


To clarify, AWS D17.1 which covers aerospace welding states that blue color is acceptable for class A welds on titanium. That covers aircraft, missiles and spacecraft. And before you ask, yes I'm positive, I looked it up today at work. By FAA regulations, we're required to have those documents on hand, and ensure that they're current.

(For a class C weld, it actually says that gray is acceptable if you can prove that embrittlement didn't take place through microhardness testing. )


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## Live Wire (Aug 27, 2007)

bee said:


> If this is a Triton weld, that is MUCH better than what they've been doing before in that first picture. Maybe their processes have improved.


No, that was Rody's weld. looks like it's from one of his handlebars.


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## bee (Apr 7, 2008)

Live Wire said:


> No, that was Rody's weld. looks like it's from one of his handlebars.


Oh. Oops. Rody's weld looks great. The Russian company? Uh, I don't know about that weld.


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## customfab (Jun 8, 2008)

edoz said:


> To clarify, AWS D17.1 which covers aerospace welding states that blue color is acceptable for class A welds on titanium. That covers aircraft, missiles and spacecraft. And before you ask, yes I'm positive, I looked it up today at work. By FAA regulations, we're required to have those documents on hand, and ensure that they're current.
> 
> (For a class C weld, it actually says that gray is acceptable if you can prove that embrittlement didn't take place through microhardness testing. )


Oh no, somebody from outside the frame building bubble has something to say


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## car bone (Apr 15, 2011)

teamdicky said:


> Someone told me it was. Not pretending to know anything about it.
> 
> True?
> 
> How about this?


That blue/purple color turns up very quickly when heating ti. Whats happening is the oxide layer increases in thickness so the light that is reemitted back at you undergoes varying degrees of destructive/constructive interference or phase cancellation if you like. Interference (wave propagation) - Wikipedia, the free encyclopedia the last color is a bit darker gray.

As everybody else in this thread knows the less color the better! That pic you posted doesn't look too bad, I would ride it. But I wouldn't buy anything more than light straw myself  I mean you buy Ti for the longetivity and durability, why would you want to degrade that on purpose, why not eliminate that potential problem? And its not like Ti frames are cheap either. I'm not saying frames with darker colors will suddenly explode but there is a reason only light straw is allowed in many aerospace applications, because they have done tests.

This makes me wonder how many ti frames have been welded inappropriately?

Or maybe I should ask, what makers are known to make it properly all the time, not cutting corners?


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