Tig welding a titanium exhaust?

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From what I understand when welding titanium both sides of the weld need to be protected with gas.  How could this be done on a titanium exhaust system?  Also titanium can be cut or ground just like stainless, mild steel etc. right?  Thanks!!!
Reply:Plug the end of the exhaust with some tape, or a plug. You only need a trickle of argon in there to get it purged- too much gas, and it will fight you on the weld. Ti needs to be treated like aluminum, ie. clean, clean , clean. Use a dedicated SS toothbrush to clean, and yes, it cuts and grinds like steel.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:The way I have seen it done for stainless is to flow shielding gas through the pipes as you are welding. I'd assume this would work with Titanium as well.
Reply:why spend that kind of money on an exhaust system?DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:Holy Crap! Ti Exaust? What is it on? $$$$$$$$$$$$$$$$$$$$$Me!
Reply:hmm... and i was happy with my rust exhaust system.The Welder Shop has great deals and reviews on Hobart, Miller and Lincoln Welders.
Reply:Originally Posted by Me!Holy Crap! Ti Exaust? What is it on? $$$$$$$$$$$$$$$$$$$$$
Reply:As stated above, you must "purge" the pipes. This process is not hard to do, but  is a little tedious.if done properly, you will have a beautiful, full pen weld. The main thing you have to acheive is proper atmosphere pressure of argon inside the pipe. If you have not enough pressure, your weld will sink in or be concave. Too much pressure and your weld will bulge out. You also need a perfect fit to maintain constant steady pressure, If your fitup has gaps, you will need a higher argon flow to get the pressure you need that turns into too much pressure as the gap is closed.The pipe needs to be sealed with an argon inlet at the lowest part and a small vent hole at the highest point. You can feel how much pressure you have by letting the argon blowing out of the hole blow on your skin.
Reply:Oh yea, you can grind on ti or use cutoff wheels basically the same as steel. just with more brighter pretty sparks.
Reply:thanks so much for the help.  Is there any way other than guesstimating how much pressure I should be flowing?  (I.E. psi, the diameter/length of the exhaust, etc.?)  BTW this is going on a Subaru WRX  that my friend has.  He has to shorten it down.  I believe it is actually coming off of another vehicle but idk what.  Thanks again for all the help!
Reply:As far as pressure goes, you just have to get a feel for it. It should feel about like a normally exhaled breath, but smaller as the vent hole should be 1/16 to 1/8 in diameter. With a vent hole that size, good fitup and no leaks it usually takes about 1 or 2 cfh to get the pressure you need. I like to use masking tape to seal the ends, but you have to be very careful to make it not leak and be sure to keep the taped part far enough away from the weld to avoid burning. I have used foil when too close to the weld for tape, but it usually doesnt seal as good. Aluminum tape doesn't help either as when the adhesive gets hot is unsticks, if you will, and leaves a mess on your pipe. Also remember that if the vent is not at the top, all the air will not drain out as argon is much heavier. Try to get the pipe in the most vertical position possible while purging. Argon flow while purging would be about7-10 cfh.Once all the air is purged you can lay it down to weld in whatever position you want. Purging time depends on how big your pipe is. For a car exhaust I would say 5 or 10 min. and the inside of the pipe should be completely inert. You really need a practice piece to play with to get it right.Last edited by Mark...; 05-09-2008 at 02:40 AM.
Reply:thanks again!
Reply:youll be fine without it but for a proper Ti weld you need a trailing sheild...pretty colors are a no no on the vessels i work on but youll be fine without =]6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:From what I have been told, when welding titanium the less color the better, and when there is no color at all, you have done it all correctly.  But this is what I have been told.. not my personal experience... I have yet to touch titanium..
Reply:Originally Posted by littlefuzzwhy spend that kind of money on an exhaust system?
Reply:i believe the 2001 and newer corvette zo6 had titanium mufflers