I have a miller sp-135 welder and have been doing self sheaded steel welding because I have not been able to find a place to buy shealding gas over here.
Now I have a bottle of 100% Argon on the way, I sunk 70,000Yen into a new gas bottle, first fill and a flow regulator.
I want to beable to do a lot with it because it cost so freaking much. I want to beable to weld: self shealded mild steel, MIG mild steel, MIG Al, MIG SS and MIG Ti; all with Argon as a sheald gas.
Local Ricers have a hunger for little things made of Ti, I hope to feed there hunger (and take there money).
Back when I bought the welder I also got plenty of extra tips and feed wheels of different sizes.
I know that you can not use the same set of tools to work Ti and steel. I will change out the wheels and tips when I change wire.
I have bought a roll of .031'' Titanium MIG welding wire.
And have been looking at Ti sheet metal on ebay to use as working stock (any one chime in with a post if you know a better place to buy Ti sheets).
So is 100% Ar ok for welding Ti?
Like for inner shealded wire (FCAW) I use a neg (-) eletrode; for GMAW AL, mild steel and SS all call for pos (+) eletrode.
What polarity should I use?
It looks like it will need pos eletrode, but I don't know.
I all ways use to GMAW welded mild steel with C25, will pure Ar be over kill or will it mess some thing up?
I was told it was over kill to use Ar on steel.
How much heat does it take to weld Ti compaired to steel?
Does it take more gas to sheald Ti, becasue I know Ti likes to turn to TiO2 when ever it gets the chance?
Any one know any sites where I can lean more about Ti welding?

 

Also, 70,000Yen is about $630.

 

welding titanium with a mig is gonna suck

 

AR is pretty much only good for welding aluminum with a MIG. Ti should weld well with a mig, assuming that you can find appropriate wire, which in most cases is a flux core that uses some shielding gas (which gas depends on the wire). The problem will be finding some wire in a size that will work in that welder.

For the most part it should weld a lot like steel, with it’s biggest peculiarity being that it gets nasty with you when you overheat it (too much heat in the weld makes it brittle, any serious discoloration greater then a straw color, like any blue before cleanup… will get a production weld rejected on the spot). The other issue is that any scratches make it prone to cracking.

AR will not work well for steel, you’ll find that the weld tries to sit on top of the steel instead of welding it together.

 

It is not flux core and it fits my welder.

 

When welding Ti, you have to make sure it's done in an inert atmosphere. Shielding gas will work on the arc-side, but you'll also need to either weld it in a deep sink being flushed w/ Argon (heavier than air), inside a bubble (filled w/ Argon, similar to a sandblasting booth), or back-purge it (w/ an extra line filling the inside of the pipe, or feeding a purge block that shields the back side of flat plates where you weld). Damn. That was a run-on sentence. Anyways, its very important the weld is shielded on all surfaces that get above the Ti oxidizing temp, or the weld will be brittle. Rainbow color is bad, mmm-kay?!!

 

I have seen welds like that and look perfect on both sides.
I know how much Ti likes to turn to some kind of TiOx and wondered about if they shealded the under side, I figured it would be hard to do and that no one bothered. And that some how it tuned out all good.
I did some serching and found that the only gases you can weld Ti with are He or Ar, even a mix of the 2. I'm guessing you could use Ne too because it to is inert but it would be super expensive.
Ar is mostly used mainly becasue it is the cheapest.
Ar is a little lighter than air I think so useing it in a puddel in a box with a open top won't work to great.
I will do the sealed glove box if I have to.
It can't be to much lighter becasue .8% of the air is Ar.

 

Argon (1.784 kg/m3) is actually denser (heavier) than air (1.29 kg/m3), not lighter. Just want to prevent misinformation out there...