TIG question (arc problems)

[Sodo]

Was trying to weld some SS, 1/16" thick with the MultiMatic200 (with Miller TIG kit). Had an awful time getting an arc started. Sometimes it would just make a conical halo around the sharp cone-tip of the tungsten. And when I did get a real arc going, the arc seemed hotter than the 'settings' was difficult to control. Ground clamp was set directly to the work, and was clean I think. Never got anywhere. Any ideas?

 

[LD1]

How are you grinding the tungsten?
What was the amperage?
How far away from the part were?
What machine and what all settings do you have available to adjust?

 

[Sodo]

Tungsten ground (parallel) on a beltsander. Previously when all was working I was using a flapper disc. That's the only change I can think of.

I don't recall the amps, because the machine has a 1/16" (thickness) setting. It does display the amps for that setting but I don't remember. Will try again and pay attn. Not sure I can say how far away, was trying anything to get the arc started but generally from 0 to 1/16" away. Basically it acted like it was trying to arc anywhere OTHER than at the point.

 

[LD1]

Sounds like a ground issue. I know you said it was clean/tight, but if I am picturing what you are describing correctly, it is exactly what happens when I forget to clamp the ground on.

 

[Shield Arc]

I'll bet it's the way you are sharpening the tungsten. Use a drill motor on a dedicated grinding wheel. Don't use the grinding wheel for anything but tungsten.

 

[Gary Fowler]

If your ground is proper, it could be a shielding gas problem. Is it a new bottle? It may be contaminated. IF you have used the gas bottle previously with good results, check the fittings on the torch all the way from torch to bottle. A loose coupling will suck air inside the hose and mess with your arc and weld.

 

[Sodo]

Hmmmmm. First welds offa fresh filled bottle. The valve was shrink-wrapped with the gas company's wrap.

I use these "CPC" gas fittings, always purge the short line off the regulator and hook them up with gas flowing. The other connector to the welder has a shutoff, it seals when disconnected and holds the gas in the line.

 

[C4Ranch]

Power source? Are you using generator?

 

[Sodo]

Not this time, its house current.

 

[C4Ranch]

Not this time, its house current.

Interesting... I got same genny as u and was stick welding with it yesterday on my Lincoln 210mp and it worked fine but arc behaved a little different...

My money's on post 5. Dedicated wheel...possible contamination if not..

 

[Sodo]

Ground clamped was directly to the shiny SS part, should be good, but I will clean it further to eliminate that. The beltsander had sanded some steel recently & since the misbehavior is at the tungsten I'm thinking its' got steel contamination. The initial arc is OK for about one second, then it does the halo thing. So I suspect the steel bits on the surface are causing trouble as soon as the tungsten gets hotter than steel's melting temp. That's probably it. If not it was a good theory.

Will try the flapper disc that has done nothing but tungsten. I've learned why TIG welders have dedicated TIG grinding wheels...

#1) of course, the cleanliness.

but nobody ever says #2......

#2) you spend a LOT of time re-grinding the tungsten. It needs to be quick and easy. Even picking up the angle grinder, positioning it, then waiting for it to spin-down, and not setting it down where it will get contaminated, takes a lot of time when you have to do it so many times for one stinkin' little weld job.

 

[Shield Arc]

I'd get rid of that regulator, and buy a flow meter for Tig welding.
HTP Argon CO2 MIG TIG Flow Meter Regulator Welding Weld | eBay

 

[Sodo]

This regulator is the one supplied with the Miller TIG kit. It worked fine before (apparently). Although I was a little surprised how fast I used up a 50CF bottle.

What difference would you expect betw. the two?

 

[Shield Arc]

What difference would you expect betw. the two?

Accuracy!
I had two shifts of welders splicing these 10-feet in diameter pipe just down river of the Bonneville dam. Running 1/16" dual shield. 100 % xray. I bought all regulators, the welders refused to use them, they wanted flow meters.

 

[BukitCase]

"I was a little surprised how fast I used up a 50CF bottle" - if your settings are right, that bottle would only last 2 - 2-1/2 hours - if it was 'WAY shorter than that, you might have been looking at the RED setting scale (LPM) - although I doubt you would make that mistake, it might also explain the crappy arc

You ARE using straight Argon, right??? Steve

Also, on tungsten grinding SA forgot to warn you - you don't wanna run the drill more than its SLOWEST speed using the drill/grinder method, or you'll put a SPIRAL/CONCENTRIC pattern on the tungsten - that can REALLY mess with your mind...

 

[Sodo]

I twirls the rod in my fingers. I get the point I want grinding it cross-ways on the angle grinder using a flapper disc. Then the last twirl is a slow 'polish' (possibly shinier than anything Steve has ever seen) and the very fine scratches are axial to the tip.

I think I figured out the "arc halo" problem. Going back to using my "ONLY TUNGSTEN" grinding disc did not solve the problem. It may help but it wasn't the problem.

When I first press the pedal, the gas flows forcefully, then it steadies at a lesser rate. So it's like the gas flow is too much at first, like it's doing a 'purge'. If I start the arc immediately after pressing the pedal, it has that Halo problem. If I wait for just about 1 second for the gas to slow down,
then do my :thumbsup: "LIFT arc" :thumbsup:
then the arc starts normally. What a relief. Not sure how that came up, maybe I was just welding faster!

Heres a stainless motorcycle protection bar 'repaired'. Man this TIG is fun stuff!

 

[Shield Arc]

Your welder doesn't have pre, and post flow?

 

[Sodo]

Well I guess it does!

I was probably just doing my :thumbsup: "LIFT arc" :thumbsup: too soon. Going off all half-cocked like some young feller! After I release the pedal the gas flows for a few seconds too.

 

[Shield Arc]

Most welders have a timer where you set the amount of time for pre flow, before the power comes on. And you can set the amount of time for post flow.

 

[Sodo]

Not this welder, it's not much bigger than a welding helmet. It's all pre-set but I can change wire speed & voltage. I have to learn to work with the pre-sets.