[Aleroux1080]

Hey all,

This is my first post. love the site, love the forum, love tig welding.
I am just starting to learn tig and have been running practice beads on a piece of flatbar mild steel, 1/4 "thick 3"x 6" or so. Dipping it in water to cool between every 4 or so beads to keep heat down and add seat time. I cleaned it pretty good with a flap disc but it did have a few very small pits in it, acetone afterwards and then on to laying beads. The first 4 before the water dip were decent but after that downhill mostly. I dipped it, wire brushed it, acetoned it and then started laying beads again. Like a volcanic eruption there was spitting and crackling and craters. Nasty holes that seem to multiply Everytime I got near them with the torch and rod. Is this a cleanliness issue? Maybe a tungsten dipping in puddle issue? A gas leak issue? Dirty tungsten issue? I varied my amps between about 100 and 140 with both 1/16 and 3/32 tungsten 1.5% Lanth both. CFH around 13-18 or so, filler was 1/16 70s2 wiped down before use and clipped if not Sheilded properly. Like I said, I cleaned the material before welding and after dunking. Maybe not to the best of my ability but still fairly clean... Maybe just not enough

Any ideas?
Comments are appreciated! Thanks

Andre

[Mike]

Alerox1080 I dont tig but I will say welcome to the forum.

[AFSATCOM]

I had a similar problem a while back. It was zinc coming up from the underside and reacting with the silicon in the 70s-6 I was using.

You problem sounds like contamination. It could be introduced in a number of ways. Seeing as the problem started after you dunked the plate I would start looking there. Is the plate drying completely afterwards? Is there somthing in the bucket that could be adding contaminants?

[Aleroux1080]

Tightened and checked and tightened more all my gas lines last night. I'm almost certain it's a moisture/contamination issue. Will try a new piece today.

[AFSATCOM]

Yea lines don't just go bad like that and if the tungsten looks clean it probably is. There's somethin else goin on

[Aleroux1080]

I was having a slow leak somewhere between bottle and solenoid, as id close the bottle valve the pressure inside the line and flowmeter would very slowly decrease to zero after about 60 seconds. Now I've got it down to about a half hour before psi drops to zero. Do any of you Teflon tape your threads?

Tungsten was clean and every time I thought I dipped it I swapped out for a clean one.

Clean steel on the other hand, I've learned it's much cheaper to pay a supplier their full price for cleanish steel than buy a bunch of rusty, bent, old stuff off classifieds and try and clean it up, even if you get a deal from the classifieds guy...

[AFSATCOM]

In my limited experience, every time there's been a gas leak or lack of gas the tungsten turns black. I don't use teflon tape as the pressure isn't high enough.

Is it a flowmeter or flow gauge? If it's a fliwmeter it should drop pretty fast as it only works when gas is flowing.

[Aleroux1080]

Sorry, it's a flowmeter but has a psi gauge before the flowmeter, so when I open the bottle it reads psi and then has a finer adjustment for cfh on the flow meter that only gives me a reading when I purge the lines or have the pedal down. It's a cheap one though and I don't really trust it for some reason.

[AFSATCOM]

Still doesn't sound like a gas problem. You might be wasting a bif of gas but any oxygen in that shield is gonna turn that tungsten black. Maybe someone eles will chime in but a still think you're introducing contamination with the dunk or just after.

[Aleroux1080]

I'm going to agree with that. Tungsten hasn't ever turned black on me.

[Aleroux1080]

Thanks for your input afsatcom and thanks for the welcome mike. I've eliminated the issues and can now continue to learn on the right path.

[AFSATCOM]

So what was causing it?

[Aleroux1080]

Had to be condensation or micro rust or just general dirty conditions. Did the same exact thing today without dunking at all, instead waiting for the piece to cool, same steel cleaned to almost sterile and only one small bit of porosity. Also moved the ground clamp closer.