Welding Tips and Tricks

does anyone have any experience in welding Titanium to Titanium? or stainless steel to Titanium? i have found very little information of either.

Yes

so what is the best practice to accomplish either?

So your going to need to narrow it down. Metal thickness, actuall metals involved. Lot of difference between 316 and 304, not to mention other grades of metal. Joint configuration, is this flat work or pipe? How big are the pieces? Lots of variables, anything you can do to be more precise will get you better answers.

i tried getting a titanium O2 sensor bung welded to my titanium exhaust for my motorcycle. the thickness of the exhaust is approximately 1mm the bung was approximately 5mm thick. the bung was titanium and i bought titanium filler rod. both ends of the exhaust were capped and the exhaust was filled with constant argon, but the weld did not stick. would there be a way to get a 304 stainless bung to hold a weld to the exhaust?

jwaller350 wrote:i tried getting a titanium O2 sensor bung welded to my titanium exhaust for my motorcycle. the thickness of the exhaust is approximately 1mm the bung was approximately 5mm thick. the bung was titanium and i bought titanium filler rod. both ends of the exhaust were capped and the exhaust was filled with constant argon, but the weld did not stick. would there be a way to get a 304 stainless bung to hold a weld to the exhaust?

In short, no. Not with out custom making a bi-metallic part.

What I would have done is turned down the [end of the] titanium bung to about 2mm. That way it is a closer match to the tubing. Then I would have practiced on a few junk parts until I got my TIG parameters straight. I've played with titanium down 0.028", and it's very finicky, but not impossible.

would there be a better filler rod to use than the titanium filler rod? it welded to the bung great but did not stick to the exhaust.

jwaller350 wrote:would there be a better filler rod to use than the titanium filler rod? it welded to the bung great but did not stick to the exhaust.

No, you can't weld titanium to titanium with anything other than a titanium filler rod. It's not like steel where you can use a variety of maintenance alloys that are nickel/chromium based. Titanium only.

okay great. thanks for all the help!

You cannot weld titanium to stainless, at least with any of the conventional processes a typical commercial or home shop uses, SMAW, GMAW and GTAW.

There is plenty of information on welding Titanium available online.

jwaller350 wrote:i tried getting a titanium O2 sensor bung welded to my titanium exhaust for my motorcycle. the thickness of the exhaust is approximately 1mm the bung was approximately 5mm thick. the bung was titanium and i bought titanium filler rod. both ends of the exhaust were capped and the exhaust was filled with constant argon, but the weld did not stick. would there be a way to get a 304 stainless bung to hold a weld to the exhaust?

Not a chance. Ti to Stainless is not possible at home. You need to find and use a stainless bung. Then purge weld it with 308 or 316 filler.

You "could" machine a thread receptacle from stainless, weld that to the exhaust, then thread in the Ti bung. Lot of work for nothing. Just get a stainless 02 sensor bung.

cj737 wrote:

jwaller350 wrote:i tried getting a titanium O2 sensor bung welded to my titanium exhaust for my motorcycle. the thickness of the exhaust is approximately 1mm the bung was approximately 5mm thick. the bung was titanium and i bought titanium filler rod. both ends of the exhaust were capped and the exhaust was filled with constant argon, but the weld did not stick. would there be a way to get a 304 stainless bung to hold a weld to the exhaust?

Not a chance. Ti to Stainless is not possible at home. You need to find and use a stainless bung. Then purge weld it with 308 or 316 filler.

You "could" machine a thread receptacle from stainless, weld that to the exhaust, then thread in the Ti bung. Lot of work for nothing. Just get a stainless 02 sensor bung.

How would that work though if his exhaust is titanium?

Oscar wrote:

cj737 wrote:

jwaller350 wrote:i tried getting a titanium O2 sensor bung welded to my titanium exhaust for my motorcycle. the thickness of the exhaust is approximately 1mm the bung was approximately 5mm thick. the bung was titanium and i bought titanium filler rod. both ends of the exhaust were capped and the exhaust was filled with constant argon, but the weld did not stick. would there be a way to get a 304 stainless bung to hold a weld to the exhaust?

Not a chance. Ti to Stainless is not possible at home. You need to find and use a stainless bung. Then purge weld it with 308 or 316 filler.

You "could" machine a thread receptacle from stainless, weld that to the exhaust, then thread in the Ti bung. Lot of work for nothing. Just get a stainless 02 sensor bung.

How would that work though if his exhaust is titanium?

Pardon me, I have it backwards. I read that his exhaust was stainless. You'll need a Ti O2 bung.

Look here for one: https://www.ticonindustries.com/collections/bungs

Oh ok, yea it's just a matter of mis-matched [thickness] parts I think. I'm sure it would be possible but it's a job for a seasoned pro. Also, the diameter of the filler rod wasn't mentioned, but for something like this, I imagine very very thin filler would be needed, something along the lines of 0.020"-0.030" diameter.

My first thoughts are you 100% sure the exhaust is Ti? Is it from a reputable sorce. The second would be is there any type of coating on the exhaust? How did you prep the exhaust?

JohnMc wrote:My first thoughts are you 100% sure the exhaust is Ti?

This.. If it's a manifold or similar 'hot' section close to the engine then titanium is not used very often.

That's usually the area where inconel and stainless (321 if you're fancy ) are used.

After a cat, yeah, titanium can be done. (can even do final silencers from alu..)

Also, was the exhaust used in anger? (aka. how hot did it get and is it oxidised?)

When talking to guys that do this for a living and who weld Ti exhausts, welding on a used stainless exhaust can already be annoying because of the oxidation and contamination making it hard, but welding on used Ti exhaust pipes and getting good results seems to be a nightmare all on it's own.

Needs to be sanded, cleaned and polished free of any oxidation and contamination in the weld area to have a chance of working.

Bye,, Arno.