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tungsten sharpening - help
Posted: Thu Mar 07, 2013 9:16 pm
by modelA
I have watched Jody's videos and noticed how fine an arc he can create in every scene. I have tried grinding my 2% lanthaneted tungstens on a regular 6 inch oxide wheel, then fine finishing it on a diamond wheel. I've read a good article on the oxides in the tungsten and the proper procedure in grinding, however, I cant get an arc similar to his videos. My 7 inch tungsten is now about 3 inches, which means I've ground it down about 50 times. I'm very new to TIG welding, no problem with MIG or stick. I was shorting the electrode to ground often until I shortened the electrode to about 1/8 from the # 4 cup. I'm using pure Argon. The arc seems to be very erratic. HELP, please tell me what you think I'm doing wrong
Re: tungsten sharpening - help
Posted: Thu Mar 07, 2013 9:20 pm
by Otto Nobedder
Welcome, modelA,
This question is better suited for the TIG forum, so I hope you don't mind me relocating it there. The "instructions" forum is more of a how-to on using this forum.
Steve S
Re: tungsten sharpening - help
Posted: Thu Mar 07, 2013 9:34 pm
by Otto Nobedder
Are you asking about DCEN TIG, i.e. steel, stainless steel,
Or aluminum on HFAC.
The answer to your question is very different for these two circumstances.
Steve S
Re: tungsten sharpening - help
Posted: Thu Mar 07, 2013 9:46 pm
by modelA
Steve:
I'm using it on thin mild steel, DCEN, TIG. pure Argon gas, flowmeter set at about 8 LPM at the flowmeter. often I end up with a big ball on the tungsten about 1/8 to 3/16 up from the tungsten tip which I cant explain
Thanks
Re: tungsten sharpening - help
Posted: Thu Mar 07, 2013 9:48 pm
by modelA
Steve:
I'm using it on thin mild steel, DCEN, TIG. pure Argon gas, flowmeter set at about 8 LPM at the flowmeter. often I end up with a big ball on the tungsten about 1/8 to 3/16 up from the tungsten tip which I cant explain
Thanks
Re: tungsten sharpening - help
Posted: Thu Mar 07, 2013 10:34 pm
by Otto Nobedder
Balling on the tungsten, at the low amps required for what you're welding, suggests a machine problem.
The tungsten should not be balling unless you are having some DCEP component in your welding.
Are you sure the machine is accepting the DCEN setting? Meaning no "buzz" noise while welding?
Steve S
Re: tungsten sharpening - help
Posted: Thu Mar 07, 2013 10:42 pm
by Otto Nobedder
Okay, I re-read your original post, and added the "balling" tungsten.
Is your machine "switchable" from negative-AC-positive? If so, you want your stinger to be negative.
If your machine is only switchable from AC to DC, you want the ground clamp to be on the "+" terminal of the machine, and your torch to be "-" or negative.
For DC TIG, your tungsten should always be the "-" (negative) side of the circuit, or your tungsten will always form a ball.
Steve S
Re: tungsten sharpening - help
Posted: Fri Mar 08, 2013 9:28 am
by modelA
Steve:
Its an Everlast PowerPro 205, which is connected properly with DCEN, AC/DC switch set to DC. I doubt very much that it is the machine, there is no HUMM as in the AC frequency, I'm sure its how I have been grinding the tungsten or possibly torch angle. Also the fact that I'm a noob with TIG. The balling up usually happens when I short the tungsten to ground when getting the tip too close to the work. I have been able to weld the mild steel with it but my arc is just not as nice as Jody's and it doesnt last long before it starts arcing all over the place.
Re: tungsten sharpening - help
Posted: Fri Mar 08, 2013 2:00 pm
by modelA
I did more practicing today on sheet metal, I found the problem I was having with the trungsten being dirty and partly balling up was because the metal was not clean enough, put some acetone to it andsince I was doing a couple inches of weld at a time, I wire brushed the area before restarting which helped very much. Spoke with Duncan at Everlast.ca who helped a lot. sure is nice to have their support, they are providing a great service.
Re: tungsten sharpening - help
Posted: Fri Mar 08, 2013 8:01 pm
by Otto Nobedder
Glad you seem to have it resolved!
I've had issues with contamination, but couldn't connect the dots for a "balled" tungsten from that. "balled" usually means too hot... Too small a tungsten for the amps, too much EP on HFAC, something similar.
Contact with the puddle will often give you a "ball" of the parent metal or filler rod at the end of your tungsten, sometimes in a "teardrop" shape, and your arc changes color and wanders.
I'm sorry I didn't catch that... For HFAC on aluminum, "balling the tungsten" is part of the procedure, especially with pure tungsten, so I thought it was the tungsten itself melting in a ball.
Steve S
Re: tungsten sharpening - help
Posted: Fri Mar 08, 2013 8:43 pm
by modelA
Steve: Maybe I should not have called it "balled up", Maybe I should have said, the tungsten seems to attract slag or impurities about 1/4 to 3/8 inch from the tip (the portion inside the ceramic cup). from this point to the end of the tip the tungsten looks dirty, almost black. I end up grinding this off then regrind the tip the best I can. I cannot usually do more than four inches of weld on this 16 gauge sheet steel before the tungsten gets real dirty and the arc seems to be going every where. I swear the arc is jumping around inside the ceramic cup rather than being directed to the metal I'm trying to weld on. I'm using a # 5 cup with 1/16" 2% lanthanated, Argon was set to 8 LPM, now its set at 6 LPM. The tungsten is sticking 1/8 to 3/16 inch out of the cup. That part of the tungsten that I'm grinding the crud or slag off has a rough surface after I'm grinding, could the arc be trying to jump off that portion in the cup ? Cleaning the metal with acetone has helped a lot but still can only do about 4 inches before regrinding
Re: tungsten sharpening - help
Posted: Fri Mar 08, 2013 9:04 pm
by weldin mike 27
Hey,
Make sure your are grinding the tungsten parallel to its length. If you grind it across the length you will get an erratic arc. Also make sure the wheel you are using is clean, impurities can be picked up from the wheel. One of Jodys' tricks is to put the tungsten in a cordless drill and spin it while grinding it, this produces a really fine polish on the electrode. If it is really contaminated, its better to snap off the cruddy bit and re grind it. This is done over a sharp hard edge like the bench, and a quick blow with a hammer. Also if there is any mill scale in your job, sand or grind it back to shiny metal.
Also, if you accidentally touch the filler metal to the electrode with out noticing that will cause the lump you were talking about. On dc steel, I think you can actually dip the tungsten into the weld pool and not really notice. It wont explode like it does with AL.
Mick
Re: tungsten sharpening - help
Posted: Fri Mar 08, 2013 9:26 pm
by Otto Nobedder
Make sure you don't have a leak in the line. Get a spray bottle of soapy water ready, plug the cup with your thumb, and check it end to end.
You'd think the "positive pressure" in the line would make it leak out. Not so. It leaks in, like the way a carburator makes gas get in the air.
Check this, please, from bottle to torch head. Your tungsten should not darken at all on a clean weld. I've used the same one for eight hours without resharpening (rarely
).
Steve S
Re: tungsten sharpening - help
Posted: Sat Mar 09, 2013 1:16 pm
by lazerbeam
It was most likely a teardrop caused by dipping the tungsten in the molten pool and then the tungsten sucks up the parent metal. My students keep the path to the grinder hot when first learning to tig. Cut or snap off the teardrop and resharpen and keep your clearance as uniform as possible. And even Jody will dip a tungsten every now and then.
Kevin