Help a TIG noob out

Nardy · Tue Dec 29, 2015 9:14 pm

First post, so go easy. I recently bought myself a 200A AC/DC inverter TIG welder, for various uses around my workshop. I've always had a MIG, but never a TIG and have never welded TIG until now.

Anyway, I had some stainless tube lying around that a mate had given a while ago, so thought I'd use that to practice on, as well as some mild steel I had. Apart from the usual learning process and playing around with the various settings, one issue I had was that no matter what I did, the stainless tube always ended up with a white/brown ring around it. I tried varying the gas flow, changing the cups, lengthening/shortening the electrode, etc etc. But I always ended up with the white/brown ring. Kinda looks like the same stuff you get when you weld galvanised steel.

What is it and what am I doing wrong? I'm using 316 filler rod. (also, please excuse my crappy weld, I've got a long way to go)

soutthpaw · Tue Dec 29, 2015 10:31 pm

How are you cleanings your weld area prior to welding it? You are using 100% argon gas right?

Sent from mobile. Not responsible for Typos

Poland308 · Tue Dec 29, 2015 11:07 pm

If your flow rate is too high on gas flow it can suck in air around the cup. Or if your running too hot on thin wall tube that isn't purged internally it can pull crap up through the molten pool of metal.

dave powelson · Wed Dec 30, 2015 1:40 am

Nardy wrote:First post, so go easy. I recently bought myself a 200A AC/DC inverter TIG welder, for various uses around my workshop. I've always had a MIG, but never a TIG and have never welded TIG until now.

Anyway, I had some stainless tube lying around ... the stainless tube always ended up with a white/brown ring around it. But I always ended up with the white/brown ring. Kinda looks like the same stuff you get when you weld galvanised steel.

What is it and what am I doing wrong?

-how do you know this is SS?
white/brown ring--indicates this is some form of plating or coating that's burning away and the pic sez-so, too.

Nice grey shade of the puddle means too much heat and/or too slow speed, not enough gas coverage….but we're getting ahead of the ring problem.

MosquitoMoto · Wed Dec 30, 2015 1:40 am

Poland308 wrote:If your flow rate is too high on gas flow it can suck in air around the cup. Or if your running too hot on thin wall tube that isn't purged internally it can pull crap up through the molten pool of metal.

What Poland said.

You can be doing everything right on the torch side, but if you are running too hot, the oxidation from the other side (you always have to purge the back side of stainless, or use Solar B Flux) will draw in oxidation to the weld side and you'll be in trouble right away.

Kym

Nardy · Wed Dec 30, 2015 2:01 am

Well it might not be stainless, I just assumed it was as he told me it was, how can I check? I just ran a magnet over it and the magnet sticks pretty solid, unlike the stainless keg I have, which only mildly attracts the magnet. So I'm guessing not stainless? And as for the possible coating, I did hit it with a wire wheel beforehand to clean it up, would that not take off the coating?

And I was wondering about the grey/blue coloured weld. Too much heat hey? I tried turning down the amps but just get a small bead sitting high. That tube is 4mm thick by the way.

Nardy · Wed Dec 30, 2015 2:04 am

Oh and cheers heaps for the comments, much appreciated. I'd be interested in any other tips on what I'm doing wrong.

Oscar · Wed Dec 30, 2015 3:42 am

Nardy wrote:Well it might not be stainless, I just assumed it was as he told me it was, how can I check? I just ran a magnet over it and the magnet sticks pretty solid, unlike the stainless keg I have, which only mildly attracts the magnet. So I'm guessing not stainless? And as for the possible coating, I did hit it with a wire wheel beforehand to clean it up, would that not take off the coating?

And I was wondering about the grey/blue coloured weld. Too much heat hey? I tried turning down the amps but just get a small bead sitting high. That tube is 4mm thick by the way.

Your magnet test pretty much verifies it is regular mild carbon steel, likely galvanized or zinc plated of sorts.

Wire wheels do nothing for you. They just polish whatever you run them over. They don't remove anything unless you sit there for a couple of hours with a lot of pressure. Abrasive flap discs or hard grinding discs are what are used to remove material, whether thin or thick. Don't worry about weld colors for now. First priority is ditching any tubing you have in sight and practicing on clean flat plate. Use a coarse flap disc or hard grinding disc and remove the millscale until you see clean, shiny bright metal. Anything else is just polishing, again you don't want this. Acetone is also good to have to remove oils/surface contaminants.

You need to get similar to this, but on flat plate. You can't get this with a wire-wheel.

See that?

Then practice running beads with uniform width and spacing. Worry about colors later. Crawl before you walk.

dave powelson · Wed Dec 30, 2015 3:50 am

Nardy wrote:Well it might not be stainless, I just assumed it was as he told me it was, how can I check? I just ran a magnet over it and the magnet sticks pretty solid, unlike the stainless keg I have, which only mildly attracts the magnet. So I'm guessing not stainless? And as for the possible coating, I did hit it with a wire wheel beforehand to clean it up, would that not take off the coating?

And I was wondering about the grey/blue coloured weld. Too much heat hey? I tried turning down the amps but just get a small bead sitting high. That tube is 4mm thick by the way.

-wire wheel takes some coating off…..then smears the rest around and impinges it further into the surface.
That crescent of crusty orange/brown at the puddle start sez the coating is sizzling.
Scrub with 3m pad & acetone; wipe dry, scrub again, then try light sanding with new abrasives, then scrub again, dry.
The arc will show unusual flaring and color when encountering contamination coating, but the best/easiest clue
is the substrate appearance just outside the puddle…..the crusty orange/brown ring,
which I'd suspect is plastic or clear paint.
I've seen/had this happen to meeself….along with many other things….and I've got 'a little' bench time on TIG.

Nardy · Wed Dec 30, 2015 4:10 am

Thanks very much guys, all very helpful. I'll put this steel aside and go a get myself some SS plate like suggested.

Poland308 · Wed Dec 30, 2015 8:03 am

Some SS is magnetic.

rick9345 · Wed Dec 30, 2015 9:12 am

My unsolicited

opinions
Mystery metals,unknown coatings,and grandpas rusty unknown 40 year old filler rods,are a challenge to the most experienced welder.
new guy,low budget welder, and no hands on guide to help,mystery metal/filler recipe for disaster/frustration.
Suggestions,ASK LWS who is their most prolific independent welder/shop and make friends for hands on.
Community college basic course.
Post your location and ask/invite forum members for lunch/instructions.
An hours help more rewarding than days of frustration.
Learning on ones own ,not for the faint of heart.

And welcome to the club.(forum)
The home/hobby tig welder can do a wide variety of materials,but the procedures/preparation can be/are demanding
This was supposed to be short not preachy.

Oscar · Wed Dec 30, 2015 3:03 pm

rick9345 wrote: new guy,low budget welder, and no hands on guide to help,mystery metal/filler recipe for disaster/frustration.

Couldn't have said it better myself. That was me back in 2009 with my Harbor Freight 165A DC TIG welder. Was actually a good little machine, but I wanted AC, and thus the addiction began.