One hundred and one TIG questions

Hopefully you'll get more thorough answers from someone with more TIG experience but here's my $0.02 for a start...

Almost certainly way more flow than you need. Try maybe 10CFH to start.

My guess is that your polarity is reversed. That causes more of the heat to be on the tungsten rather than the workpiece. It should be the opposite of what you used for stick welding. How do you have it setup? What gas(es) are you using?

Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com

"I'm not grown up enough to be so old!"

Keith,

Thanks for the "wrong polarity" thought. But that's not it. Indeed, I'm running electrode negative.

As hobbyist welders go, I'm waaaay long on theory although in many areas way short on practice. Over the last seven years books on welding, metallurgy, blacksmithing, yada yada have been my constant companions.

In fact, I must know all there is to know about welding.

Except how to do it correctly.

But anyway, I'm clear as can be on the polarity issue.

I'm really wondering if it's got something to do with a flaw in my grinding technique, or a bottle of bad gas.

You ARE supposed to use oxygen as shielding gas aren't you?

Just kidding. I'm using what is purported to be a new bottle of pure argon. But it's been sitting there for a several years.

What does argon break down into?

Oh yeah. Argon.

Seriously, I'm eagerly awaiting the typical parade of sagacious wisdom. Sometimes I wonder if the beacons of light in here don't sometimes get tired of shining!

Tomorrow I will likely try some CLEAN metal. Maybe I'll even clean the tungsten. Then I'll get some mig wire and try to run a bead.

Thanks, Vern> Hopefully you'll get more thorough answers from someone with more TIG

I'm no expert but I know of no health issues with lanthanated tungsten other than normal precautions associated with grinding dust of any kind. Also your metal has to be clean. I have never had any luck with tig on rusty dirty metal. With a gas lens you don't need a lot of gas. 10cfh sounds about right as a start. That's about where I run mine and I have no problem with gas.

Make sure your lines have been purged. If you have a leaking connection the gas of course can stray but also you can drag air into the lines. Too much gas can cause funny things in terms of turbulence at the cup. We have that problem with our wire feed guns on MIG. Make sure there are no side drafts.... stop talking to yourself when you strike an arc. :') Randy

Oops, wrong button on the last one... :-/

I wouldn't think grinding technique would have THAT much affect on it. And if all you're doing is practicing establishing an arc the rusty metal shouldn't be that much of a problem but I'd grind a clean spot for practice and another clean spot for the ground/work clamp.

What kind of current are you running? If you're using a 1/16" tungsten you should probably be down around 60 amps or so.

Here's a good reference with a troubleshooting guide that may help:

Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com

"I'm not grown up enough to be so old!"

About grinding tungstens........All the stuff I read says you should not use a wheel that has been used on anything else. So I use a belt grinder and a belt that I only use for tungstens. Everything also says to grind so the grind marks are in line with the tungsten. I have not seen that this matters, but I use a fairly fine abrasive belt so the grind marks are not much.

If I get the tungsten in the puddle, I break off the tip and regrind. But find I don't have to break off ( or grind off ) much to have the arc looking normal.

I would turn the flow down and get some clean metal to play with. The whole idea of TIG is that the gas shields the metal so no flux is required. But no flux means that the metal has to be very clean.

Dan

I'm a newbie myself, so I feel your pain. After some horrible practice sessions, here's what worked for me. First of all you've got to keep a steady 1/16" distance of the tungsten from your work. Watch for the puddle to form and move forward right to left. Also check the angle of your torch relative to the work. Too steep an angle will cause the spark to jump sideways to the work and create all kinds of problems. Don't try and control the heat by moving the tungsten away from the work. Ideally the angle should remain the same across the weld. Go cooler (less amps) and slow down is my overall advice. I used virgin

1/16" to 3/32 mild steel pieces to practice on that I got from a local fabricator. Clean joins with emery paper and alcohol. Needs to be super clean. Practice butt welds using no filler rod. Move the puddle up the join without burning through. Simplifies things until you are comfortable with handling a filler rod at the weld. There is a formula posted by Ernie L. on the proper amperage to use for the thickness of metal. Also, check the distance your tungsten is protruding from ceramic cup. CK has some very good guidelines on that subject. As for grinding the tungsten, your tip grind length should be roughly 3 times the diameter of your rod. Again CK has some great material on this subject as well. I use a cordless drill to spin my tungsten while grinding on a dedicated grinding wheel. I grind up a bunch before starting a session. As others have suggested, check your gas flow and hoses etc. At least eliminate that as a source of your problem. Do you have foot a control? Sounds like you don't...maybe a problem, but with practice you should be able to overcome that drawback. My rule of thumb on tungsten contamination is if looks shaped weird or off color, I remove it for a new one. You can usually tell when it's bad. Never used lift and start, so I can't comment on that. I've gotten all the information I've needed to overcome my startup problems on this newsgroup...so hang in there.

-Mike

These are all good hints, but the OP's problem is that he is burning up the tungsten, which I don't understand, given that he is certain that the polarity is correct.

My advice is to just try swapping the polarity, just to see what happens. It wouldn't be the first time someone got a plus and a minus confused...

two highest achievements of the human mind are the twin concepts of "loyalty" and "duty." Whenever these twin concepts fall into disrepute -- get out of there fast! You may possibly save yourself, but it is too late to save that society. It is doomed. " Lazarus Long

Well, thanks to all.

The only thing I'm sure of that's NOT wrong is the polarity. Not only is it clear in my mind why you use positive electrode polarity with SMAW it's also clear why you use negative electrode polarity with GTAW. See? I even know the buzz words!

I'm gonna take a careful look at the possibility that I'm pulling air into the hose. I even know where the problem might be.

Otherwise, today I'm gonna make sure everything's clean. I'm even gonna change out the gas lens.

Y'all are the greatest! V

Just switch it anyway. Just for fun. Bad welds are one thing, but burning up the tungsten is another. See if it burns up faster or slower when you have switched it...

Well, Emmo,

Although at the beginning I was dead set against it, I'll do it for science and the good of humanity. But only after I've ruled out that air's being drawn in by venturi, as suggested by Randy.

However, I may do it with a stick electrode rather than a tungsten. They're quite a bit cheaper you know. It should tell me the same thing don't you think?

Vernon

It's really pretty obvious. I use electrode positive for putting a ball on the tungsten when I do Aluminium, and it turns the tungsten bright red in an instant. Negative don't do dat...:)

My guess is bad gas or air leak, too. Or just too much current, although I put 160 amps through a 3/32" electrode and get decent life.

My big question is what makes the puddle jump up and bite my electrode? I swear sometimes I haven't dipped it and a great blob of puddle just leaps up and grabs the thing... Brian

It is a fact of physics that the weld puddle of a new TIG weldor has an irritable magnetic force that will pull the tungsten into the puddle. They don't know why.

It goes away with time.

Ciao, David Todtman

David and Brian,

I concur. An irritable magnetic force is the only logical explanation.

Momentarily I will go outside and see if it can be rectified by sunspots or even flatulence.

Vernon

Emmo,

I plan to implement your plan in reverse. I'll run a stick electrode electrode positive. I'll crank the amperage down until it's hard to start.

Then I'll switch polarity of the cables. If it's even harder to start the machine's polarity is correct.

If it burns like the dickens then the lugs on my Maxstar are reversed. This will mean that all the welds I've made with the machine have gone back in time. Therefore, I've been getting younger.

But that still doesn't explain why I can't remember where I left my damned gloves!

;o( VT

My third session resulted in a series of revelations.

First and foremost among these is, I AM SUCH A DUNCE!!!

I cobbled together an air cooled torch from a pile of parts I bought on ebay. From among these pieces, and for no good reason, because I had others, I used a top cap that had a broken end. I don't know what to call it. But it's the black thing that to me, makes a tig torch look like a pterodactyl.

When I first assembled the torch and put a tungsten in it the tungsten protruded above the broken end. I rationalized this away by saying to myself that the only purpose of the cap was to prevent electrical contact between the operator and the energized tungsten.

Well, duh! Could it be that the O-ring and the gasket just above the threaded end are intended to produce a GAS TIGHT SEAL??

My only defense is that I simply never looked down in there to see what path the argon takes as it flows from the bottle to the torch.

Once I did it was immediately obvious that my mysterious air leak was RIGHT UNDER MY FRICKIN' NOSE!!!

The second revelation was that my gas regulator has three separate graduations on the glass cylinder through which you read the flow by the height of the little floating ball. One of these is for helium, the other CO2, and the third, argon. The graduations are NOT the same. And I was reading "helium".

The third revelation was that tig welding in the wind really sucks. A breeze kicked up and put an end to today's journey of learning by screwing up.

But tomorrow's a new day with fresh opportunities.

The tungsten still looks pretty beat up after a few starts. And by the way, I am running very low amperage at about 40. Therefore, I trust everybody will agree that's not part of the problem.

Admittedly, I have not tried Emmo's suggestion to swap the polarity. Emmo buddy, I will try that tomorrow.

Vernon

Are you sure about 1/16" distance? I am a TIG newb also and would find that gap damn near impossible to maintain.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)