TIG questions

Are you trying to weld through the oxides on the hot rolled angle? You can't. You have to grind off any oxides. TIG requires clean metal. No oxides, paint, rust, oil, plating, or dirt.

Oh, so you are trying to use pure tungstens on DCEN. No wonder your arc is going nuts. Use Thoriated tungstens at least, but even better are Lanthanted tungstens. They work on AC or DCEN.

Thoriated work on DCEN, but are bad on AC. Pures just suck, but they suck even worse on DCEN.

Get yourself some Lanthanted tungstens and never worry about what tungsten you are using ever again.

Check your system for leaks. Get yourself a small spray bottle, fill it with water and 1 tablespoon of dish soap. Spritz the soapy water on all your gas connections to find leaks. Just look for the bubbles.

Right, I know that. I do grind the area within about 1/2" of the weld. On the pipe, it is so smooth and clean, I tried a wire wheel and just using solvent, and don't see any difference.

OK, thanks. I go bad advice from the guy at the welding store and haven't gotten back for some different electrodes.

Thanks! I have a pack of Thoriated elecrodes somewhere around here, but I'll get some Lanthanated ones as soon as I can.

But, in this particular work, I get contamination all the way up the electrode. Something in there, I'm guessing the hot rolled, is making sparks - just like from a grinder. I'm pretty sure it isn't the pipe or the filler metal (ER70S). Is this a problem with insufficient shielding gas, or is this particular material just going to spit sparks?

I'm pretty sure there are no leaks, now. Of course, the welder was a BIG "leak" as it left the gas valve open all the time. That is now fixed.

Thanks much for all the help! I am actually getting good welds now in this mixed steel job, and really getting a good feel for controlling the arc and melt pool.

Jon

You should try some stainless steel filler rod on your steel welds to see if they settle down. Stainless can deal with more contaminated materiel. The nickle and chrome help it flow in nicely.

In addition to what Ernie has said I would advise you to not continue welding after you contaminate the electrode. Stop, clean it, resharpen it and then go back to work. You can get an accumulation of metal deposited on the inside of the cup that boils off the electrode when you continue welding after you contaminate the tip.

Richard Coke

Ernie aka, "The Man", wisely advised.................

Ernie,

Could he possibly be heating the metal past its melting point and causing it to boil? I have been guilty of this before, especially using 2 different thicknesses of metal.

Regards, Jim

PS Ernie, I have to eat a little crow regarding a comment I made in a post a week or so ago. I questioned your advice on using Zirc. tungsten for Alum. I was having problems with the arc being very unstable and the tungsten was getting corroded badly. Come to find out, the cup had a small amount of Alum. slag stuck to the inside of it. It didn't seem to bother the pure tungsten, but was playing hell with the Zirc. Changed the cup out, no more problems. So, do I get some salt to go with the crow, or is that not on my diet plan either?? 8)

JR

You can boil the steel all you want as long as it is shielded by Argon.

I have eaten enough myself for it to qualify in my low-carb diet.

OK, then either my torch without the gas lenses is not properly covering the weld area, or there is something like oxygen buried in the workpiece. I did clean all the scale off in the weld area.

And, thanks again, Ernie, for the suggestion on the Lanthanated electrodes. I didn't get them yet, but I did find that pack of

2% Thoriated electrodes I knew I had around here somewhere. They were 1/16" inch, not 1/8 as I thought, but you can weld 1/8" steel with a 1/16" electrode, according to my Lincoln TIG book. I set the current for 150 A max, and the difference was amazing. I felt like I suddenly had developed about 2 years of experience with TIG. I welded for about an hour, on and off, without having to regrind the electrode once, or even pull it out from the collet! AMAZING difference! I can't believe that anyone ever uses EWP electrodes if they perform SO MUCH worse than even 25 year old Thoriated ones! Is the differece really that enormous, or did I get some crappy Chinese electrodes made from burned out light bulbs? (The electrodes I bought at the Cee Kay store are labeled "best welds" on the top of the label, and "OKI Bering Cincinnati (sic) OH" at the bottom. Are there brands to stay away from, or to specifically ask for?)

Anyway, things are getting much better, at least in the steel department!

One more question, mostly pertaining to Lincoln Square Wave machines. I'm having a problem in the HF system. The spark gap hisses very smoothly and steadily when the HF is on, but sometimes I get no HF at the electrode. Other times, it is like a flame thrower, and I now realize I was trying to weld with the HF energy, not real welding current, when I was starting out. When it is working, I can get little lightning bolts running through the Argon from as far as an inch. When it is not working, I end up touching the electrode to the workpiece before I get any discharge. It seems after that happens, I then ALWAYS have HF on the next start. When it is not working, I can CLEARLY hear the HF spark gaps hissing. Any suggestions where to look? Is there an arc developing inside the machine, shorting out the HF? I think my cables and hoses are in very good condition.

There is a 3 Ohm 25 Watt rheostat marked HF intensity or thereabouts, and it had a problem. I thought fixing that was going to solve my HF problems, but it didn't. There was a small weld spot on the resistor element, and it had caused the graphite wiper to jump out of the claw that sweeps it across the element. I had to file down the spot so the wiper wouldn't catch. I think the rheostat is now in good condition, but I'm still getting intermittent HF at the electrode.

Thanks in advance for any ideas on this.

Jon

Right, I was pretty much aware of this. But, I was only getting 15 seconds of work before the EWP electrode was just sputtering and flashing! And, the thing looked like it had blobs of molten steel melted into the entire exposed length right up to the collet!

I switched to some 25 year old 2% Thoriated electrodes I had laying around, and they worked BEAUTIFULLY. I can't believe an EWP electrode is supposed to be that awful, so I am wondering if these electrodes are of poor quality. (Hmm, looking on the back of the box, it says "made in China". How come I thought I might find such a label there?

Jon

There are only a few companies that make tungstens, everybody else just relabels to sell under thgeir name.

They are all sintered from powder. I have never had any clear evdence that the manufacturer makes a difference

The only thing pures are good for are extremely low amperage welds on thin aluminum using AC.

Sounds like your spark gaps need to be cleaned and regapped. There should be a hatch that gains you access to the HF generator. The HF Gen has a pair of spark gaps that need to be cleaned every 5 years or so, depending on environment. You have to remove the points, clean then gently so they are flat and clean, then put them back in and set them to the factory gap. I find that puting them in a drillpress works well, and just spin a piece of silicon carbide sandpaper against the face with a flat bar backing it up. The idea is to get it very flat and smooth.

The gap is usually somewhere around 0.008". Use a feeler gauge.

Another point. Get in the habit of "Cold Scratching".

Every time you stop and arc, there is a little cloud of ionized metal particles caught in the plasma stream. When the arc stops, they will collapse onto tyhe trungsten point. These particles will form an extremely thin oxide layer that is a very good insulator. Scratch the tungsten point on your base metal before hitting the foot pedal to break through this coating. If you get in the habit of this you will get much more consistent arc strikes. Just be sure to NOT have the foot pedal down while doing it or you will contaminate your tungsten.

Well, I'm learning, slowly, what works and what doesn't. But, I got a major chunk of my first TIG project done (stand for surface plate).

They ARE very flat and smooth, and the gap is about right. They make a loud hiss, no buzzing or popping. And, the hiss is the same whether the HF is working or not on that start. So, I think it is something else.

AHHH, I think this is it! I'd never heard of this, and it isn't in any of the books, either! But, I did notice that anytime I accidentally touched the electrode to the work, I would get an excellent arc start the next time. Just that I was doing by accident, but I hadn't actually figured out the connection, yet!

Well, I did this a fair number of times with the 2% Thoria electrodes. I would get a green flash, and then it would go right back to a smooth arc. But, thanks again for getting me to give up on the pure W electrodes. Never again!

Jon