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titanium exhaust? (welding)

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  • titanium exhaust? (welding)

    greets all.
    got myself a piece of broken exhaust pipe -- its not mine,
    someone walked in the door with it. its from a fancy japanese
    motorcycle (rocket bike stuff).

    small mounting tab has broken off and he wants it welded
    back on -- here's the kicker -- he (strongly) claims that its

    I'm wondering what the odds are.

    its not the header or the muffler -- but connects the two.

    the tube is straw colored (from heat) and the end that was
    closest to the engine (manifold) is slightly magnetic. the
    rest is not.

    its been tig welded before (thats where it broke). I realize
    Ti is weldable -- i'm just wondering if this isn't actually
    stainless steel.

    my cost-to-weld will vary considerably.

    Any way to tell for sure what this stuff might really be?


  • #2
    Doesn't make sense that an exhaust pipe would be made out of titanium, it's not a load-bearing element.

    If you can grind a small part of it (with a little Dremel stone), titanium sparks brilliant white.
    Last edited by lazlo; 06-09-2008, 04:34 PM.
    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


    • #3
      TIFORCE exhaust systems are a work of art the quality and craftsmanship are second-to-none! It's easy to see why TiForce is the HOTTEST sportbike performance exhaust! You won't believe the power gains- not to mention the looks you'll fll get!
      We use the highest spec, relatively thick .040" titanium tubing. Hand-bent conical tubes are welded to CNC-bent headers/collectors. These pipes offer not only superior weight savings, but increased durability over other performance exhaust systems. Your choice to retain standard passenger pegs, an overall weight just over 9 lbs., consistent horsepower and torque gains they're a force to be reckoned with!

      $1300.00 !, yes, it doesn't make sense.


      • #4
        Originally posted by lathehand
        These pipes offer not only superior weight savings, but increased durability over other performance exhaust systems.
        Titanium is 60% heavier than aluminum. Why wouldn't you use aluminum on the exhaust if you're trying to shave weight? If you're worried about it scratching or denting, you could use (ceramic) plated aluminum and/or 7075 and still come out ahead on weight and cost.
        "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."


        • #5
          That was a quote from a google search for "titanium exhaust". I would think aluminum would soften from the heat of a race bike. I have seen them glow red. Also, what thickness aluminum would you need to be as strong as Ti? There is the thermal expansion factor to contend with for an aluminum exhaust.


          • #6
            My last bike had Ti exhaust, (headers and midpipe) from the factory, lots of the japanese literbike stuff in recent years is. Mine turned blue from heat, I bet you have stainless there. If it is OEM a call to a motorcycle dealer should clear it up.

            I have an aluminum pipe on my wifes old 2 stroke MX bike, '98 YZ125. They were really expensive back in '98. Most people can't believe it when they see it. A modern 4 stroke header can glow red hot quite easily, aluminum transfers heat so fast I doubt one would melt unless it was wrapped or really badly sheilded.


            • #7
              The Suzuki GSXR1000 bikes have Ti header pipes, stock from the factory. At some point the stock system switches to steel, at least the muffler is steel. So the guy could be right, it might be Ti, or it might be steel. Sorry I can't tell you exactly where the change occurs.


              • #8
                My stock pipe on my '98 ZX9R is Ti, mountings are well enough designed not to have cracked yet.
                You can TIG buy I think you'll need to do it in an inert gas enclosure,


                • #9
                  Can you ballpark the density of the broken tab? Weighing it shouldn't be an issue, the only real work would be determining volume. Fill a glass to a scribe line with the tab in it, remove the part being careful to limit liquid removed, then add more liquid using a dropper and medicine cup. That is about as non-destructive as I can come up with to tell between Al, Ti, and Steel.


                  • #10
                    If the crack is something that you can fuse without filler, it doesn't matter what material it is, both are suitable to weld using DC Tig, Electrode negative, HF start. I'd just be a little more dilligent with inerting if you have Ti. You could build yourself a little open top box with cardboard and tape on a welding bench and run argon into the enclosure. If you have a nice calm area the box will fill and overflow with argon and you can submerse the part, argon is enough heavier than air for this to work fine. I welded some .062 wall ti tubing, no box, just taped off the ends and backpurged with an argon hose and it was a lot like welding stainless in my opinion. I'd have a filler rod for each at the ready just in case you need it. My google searches tell me Titanium is non-magnetic and I'd repeat Lazlo's note about the brilliant white spark vs the red occassional spark off stainless.


                    • #11
                      If it is Ti.. you need to back purge it and should by all means use a trailing "gas shoe". Form this out of tinfoil... so the weld still has gas coverage as you weld. Hold the torch as straight up as you can so part of the gas flows back into the shoe. Be careful not to mash the shoe
                      I have tools I don't even know I own...


                      • #12
                        holy smokes -- this is one hell of a support group

                        haven't had my hand at the pipe yet -- i'll give a try tomorrow.

                        I'll be sure to try the spark test
                        ("hey buddy, it welded great, but sorry about the grind marks")

                        the weight is a good call too. I can weight it fairly accurately
                        and then draw it up in 3D cad to find the volume.

                        about all the backgassing / trailing shield -- standard practice,
                        I know, but I don't want to ruin a perfectly good old shoe box
                        if its not Ti.

                        if its Ti, I have no filler. and no where on the exhaust to
                        "harvest" any. I'd guess it would just crack instantly if I
                        tried a different filler -- unless there are stable mutant
                        Ti-Al-Stainless alloys?

                        thats two smileys in the same post -- time for bed.

                        Thanks again .. will report results (JB Weld!).


                        • #13
                          well according to the math, the little flange should weigh:

                          23 grams if Stainless (7.5 g/cm^3)
                          13.5 grams if Ti (4.5 g/cm^3)

                          local pharmacy has a precision scale -- flange weighed in
                          at 19.684 grams -- right in the middle of my range!

                          on the fence, my wager was on Stainless.

                          spark test: *definite* orage sparks.
                          (though this was a tough call as I've never spark tested
                          Ti before -- not sure how white "white" was supposed to be.

                          tigged it with alot of excess argon and separate shiedling
                          gas, no filler.

                          hasn't broken.. but, in the end, i still don't know what it was.

                          Thanks again for all the feedback.


                          • #14
                            A shower of bright orange sparks usually means carbon steel or cast iron.

                            Ti sparks pure white.

                            Stainless usually sparks streamers (like little comets) of pale orange.

                            I'm in Santa Clara today, but I've got a link somewhere on my home computer with videos of the various spark tests.

                            Glad it worked out for you!
                            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."