[Questor]

I'm new to welding, where I want to learn more about Mig/TIG/Resistance Spot Welding equipment and use...

I own a Miller LMSW-52T spot welding gun and a Nelson CD-312 spot welder.

I also have a vintage Titanium (almost pure Titanium) Bicycle Frame that needs needs welding repair with a replacement Titanium 6-4-1 Derailleur Hanger that attaches to the Seat Tube and Chain Stay.

I don't want to want to do the Titanium welding myself and I realize that my Spot Welders can't be used for Titanium Welding. However, I would like to see which Titanium welding equipment should be used under what controlled conditions to complete a good permanent fix to replace this broken part.

Regards, Steve

[Poland308]

Almost all of the dc tig welding machines with a low starting amps will be capable. The trick to titanium is just in the applied knowledge of the needed gas coverage. As long as you use filler that matches the application then it’s not that much different than steel or SS.

[LtBadd]

Steve, welcome to the forum, I grew up in Columbus.

[Oscar]

Almost all of the dc tig welding machines with a low starting amps will be capable. The trick to titanium is just in the applied knowledge of the needed gas coverage. As long as you use filler that matches the application then it’s not that much different than steel or SS.

Gas coverage is definitely a key item of importance. But also, when I was monkey'ing around with some titanium tubing a few years ago, I came to a realization: active heat-sinking dramatically improves the chances of success,whereby I mean not overly-oxidizing the part due to lack of an extensive argon blanket of gas.

In my experiment, I used some 1/2" wide, tinned copper braid, wrapped tightly on a thin-wall Ti tube, approximately 0.050" wall. This was done to both sides of the butt-joint.



The spacing between the wrapped-braid was only big enough to fit a #7 or #8 gas lens. (here I had not yet sliced the tube)


And it turned out great. It basically counter-acted the low thermal conductivity of the titanium by speeding up the heat flow in the vicinity of the weld bead (into the copper braid).


The inside was purged with Argon of course (if you look closely, you can see one tiny spot where you can see the weld seam where it did not penetrate through, but it was just an experiment to see the effectiveness).