Welding Tips and Tricks

I'm guessing anyone reading and adding to this forum has watched Jody's great video on tig welding thick aluminum with the help of 100% helium and DCEN. If you haven't check it out.
https://www.youtube.com/watch?v=b1dCZyH_NBI
Its impressive to anyone with a smaller tig machine like mine, syncrowave 180SD. So i decided to try it out and got a bottle of helium, but i couldn't get off the ground. My set up was using the machine mentioned above, set to DCEN, 140 amps, 2% lanth - 3/32" tungsten, and about 25 on the helium flow. I couldn't even get close to getting a puddle started. There seemed to be only a fraction of the current arcing across to the material. See the sad proof here.
https://youtu.be/4Va65VTUvbM
I just got off the phone with my welding gas supplier and asked if the helium was pure. He said that it wasn't 100% pure but had a small amount of nitrogen (i think thats what it was). Its labeled as ULTRLIFT HELIUM from Praxair. Could this be the stuff that goes into balloons? Has anyone welded with this stuff?
Ive been AC tig welding aluminum for a while now using a helium argon 50/50 mix that has been working great, so i know its not the welder, or my set up.
Any Ideas?

andrew jay 649 wrote:I'm guessing anyone reading and adding to this forum has watched Jodie's great video on tig welding thick aluminum. If you haven't check it out.
https://www.youtube.com/watch?v=b1dCZyH_NBI
Its impressive to anyone with a smaller tig machine like mine, syncrowave 180SD. So i decided to try it out and got a bottle of helium, but i couldn't get off the ground. My set up was using the machine mentioned above, set to DCEN, 140 amps, 2% lanth - 3/32" tungsten, and about 25 on the helium flow. I couldn't even get close to getting a puddle started. There seemed to be only a fraction of the current arcing across to the material. See the sad proof here.
https://youtu.be/4Va65VTUvbM
I just got off the phone with my welding gas supplier and asked if the helium was pure. He said that it wasn't 100% pure but had a small amount of nitrogen (i think thats what it was). Its labeled as ULTRLIFT HELIUM from Praxair. Could this be the stuff that goes into balloons? Has anyone welded with this stuff?
Ive been AC tig welding aluminum for a while now using a helium argon 50/50 mix that has been working great, so i know its not the welder, or my set up.
Any Ideas?

http://www.praxairdirect.com/Product2_1 ... 1_11537___

All of them except the last size claim 99.995% purity, which I believe is the standard weld-grade helium with 50 PPM other constituents. Something is definitely off. Even if it was/is what is used for ballons, the purity seems high enough to work for welding

Then again, they seem to have a different line for welding: Helium - Industrial

My .02c is that the balloon grade helium could be filming the tungsten. When we were using pure helium ( from memory it was welding grade 99.998% purity ) with a Syncrowave 350 on AC, it would film the ball and you had to sort of scratch start; wipe the ball on the part and hit the pedal when you were lifting. With a fresh tungsten, no problem. And if you have any 2% thoriated, use that.

http://askzephyr.com/what-are-the-diffe ... -used-for/

Try grinding it clean, also up the flow rate to around 40-45 cfh on an argon meter. It was always my understanding that only welding grade helium should be used. If you do get a puddle, you will probably get, at best , a very sooty weld.

I'd change the bottle to eliminate one variable.

Maybe other suppliers are different but my Airgas rep tells me they only refine one grade (research I think) and then they sell it for different prices depending on the label.

-Sandow

Thanks for the helium info Oscar and Kiwi2wheels and Sandow for your input on it.
I now think the Helium is not the problem. I think its about the surface, the distance of gap between tungsten and work , and the absence of ac cleaning.
What Kiwi2wheels said got me thinking, so i resharpened the 2% lanthinated a bit more acute, then tried getting in unusually close. I started off touching, then rocked back a hair, started the arc and rocked in til i basically was touching but just for a second to start the arc. Once it starts and full current is crossing the tiny gap you can pull back a bit. Maybe an 1/8". The welding is smooth and quiet but really hard to read. The surface layer of oxides that float up makes laying in your filler pretty tough, but i can see with practice this will make a great technique to know about. It is a lot harder to do than the "traditional" AC approach, but i'll work on it now that i have the helium. I put up a "part two" video (link below). Its pretty hard welding around a camera (i don't know how you do it J) so forgive the shaky handwork. You'll see that i had made a little tack on the piece (which was done at 80 amps.. not enough) and the rest is done at 120 amps with a 2% lanth - 3/32" dis, and about 1/4" stick out, base material is 3/16" bar to 1/2" square 6061.

https://youtu.be/vOFuHnJ_Wzo

The one thing I'm totally puzzled about now is the intensity of the light. I have new miller auto darkening helmet that i use every day for tig and the light coming off this 100% helium DCEN weld is totally different and not fully blocked by any means. I put on a pair of brazing glasses under my helmet and that made it possible to see just enough. Any ideas on that?

ADDITION/EDIT to the last paragraph above from yesterday

It must be the sensor on the helmet that is sensitive to this process somehow. I ran a whole series of these welds this morning without any flashing/over-brightness issue, and then out of the blue it happened again,.. and then was fine again.

Just wanted to add that I'm now using a (new to me) used syncrowave 250 to do this same technique and I'm not having any of the same issues with starting up the weld or any of that flashing i was last getting using my sync 180 SD. Im not sure but i think that the HF start is better or just different on the 250. It doesn't seem to have the same trouble lighting up in this mode, where as previously i was needing nearly to touch the material to get it to start.

Some machines just will not support an arc with pure helium. I personally seen this. Terry an argon helium mix. You may also need higher flow as well.

Sent from mobile. Not responsible for Typos

not that i intend to try pure helium but is there
a way to determine if a machine is capable of
using pure on dc?
craig