Settings for 16 ga square steel tubing?

Anyone care to hazard a guess at where to start for tigging 16 ga mild steel square tubing? I haven't yet had time to fire up my PP256 yet, but intend to this weekend. I plan to practice on cutoff pieces I have hanging around, but don't really have any idea of what to expect. I've spent plenty of time MIGing this stuff and know there's a fine line between achieving penetration and blowing holes when joining tubing at right angles. I suppose it's the same with TIG.

Any thoughts on where to set up for my initial efforts?

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Originally Posted by Slartybartfa

Anyone care to hazard a guess at where to start for tigging 16 ga mild steel square tubing? I haven't yet had time to fire up my PP256 yet, but intend to this weekend. I plan to practice on cutoff pieces I have hanging around, but don't really have any idea of what to expect. I've spent plenty of time MIGing this stuff and know there's a fine line between achieving penetration and blowing holes when joining tubing at right angles. I suppose it's the same with TIG.

Any thoughts on where to set up for my initial efforts?

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these calculators come in handy.....
http://www.millerwelds.com/resources...calculator.php

ken

The rule of thumb is one amp per thousand. 16 gauge is .065 so about 65 amps would be a good starting point. Practice on the scrap pieces first is a great idea.

DCEN of course.
1/16 filler rod

A fair question: the Everlast TIG welding calculator
http://www.everlastgenerators.com/ti...calculator.php
... doesn't mention mild steel. Do the stainless steel settings apply to mild steel?

Thanks for the reference. I bookmarked that.

If you are using the foot pedal, you will be making your fine adjustments as you weld. Everyone has their own style to that. Some people like to have the welder setup to the current they expect to use and just use the pedal for tapering off, doing most of the weld with it "floored". Others like to have power above and below the expected level and will set the welder so that they weld at about the half throttle position. Then you have some extra power on tap for thicker areas or places where you can't get in as close. Being able to play with the heat is one of the biggest advantages to TIG welding.

Not that I haven't used a foot pedal for stick welding, too, cause I have. ;)

Foot pedal would be the best bet so you can back it down if needed. If your not using the foot pedal I would probably set it around 75 amps and adjust the travel speed accordingly. For Sure make a few practice runs before you do the real thing!!

Excellent points. I forgot about the foot pedal. So when you're running pedal, is the setting the base current, and when you step on the pedal the current increases, or do you set the pedal at some position (off, middle or floored) and then set the current? I suppose it's the latter.

Picked up some cutoff pieces of 16 ga or thereabouts steel scraps at the local metal supplier to practice on first. And I have plenty of aluminum and might work on that as Jody suggests doing to learn how to get the hang TIGing. Looking forward to this. Been welding MIG for 10 years and stick for longer than that. Moving from stick to MIG was a life-changing experience. I expect having full control of heat, metal deposition and travel speed with TIG will be equally life-changing.

You want to set the welding machine higher on amps than you think you need. I think they say you want the amperage you will be welding at to be at around 3/4 pedal so you have a little headroom incase it's needed. Really I just set it close and see what happens.
I got in the habit in school to set the max close to what I need and then just mash the pedal to weld(which sort of defeats the purpose of the pedal), But I can still lower the heat if needed when welding that way.
NOW, I rarely use the pedal, even on Aluminum. I just set the amps. and control the heat with my speed. I'm usually in a funny position and getting to the foot pedal is tricky.

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Originally Posted by Slartybartfa

Excellent points. I forgot about the foot pedal. So when you're running pedal, is the setting the base current, and when you step on the pedal the current increases, or do you set the pedal at some position (off, middle or floored) and then set the current? I suppose it's the latter.

Picked up some cutoff pieces of 16 ga or thereabouts steel scraps at the local metal supplier to practice on first. And I have plenty of aluminum and might work on that as Jody suggests doing to learn how to get the hang TIGing. Looking forward to this. Been welding MIG for 10 years and stick for longer than that. Moving from stick to MIG was a life-changing experience. I expect having full control of heat, metal deposition and travel speed with TIG will be equally life-changing.

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The panel setting is your max current and the pedal will take you from zero to that max setting.
Steel is more forgiving so it's a good place to start. Aluminum has more character and more gotcha's but it will make you a better welder in all metals. I think you get a better feel for the puddle in aluminum, and it's usually bigger and easier to see, as well.

Well the machine works fine. But the welder ought to be fired for incompetence.

First, was burning up electrodes. Something was really wrong. Balled up the 1/16" 1.5% lanthanated electrode three times all the way back to the collet holder in seconds. Was only running 60 A. Had plenty of argon. Checked the settings, then saw the ground was positive. Shoulda' been running DCEN, not DCEP. DUH!

Then reset everything and got a decent arc, electrode tip glowing nicely, but awfully hard to see 'cause reading glasses under my helmet just don't have the magnification I need to see the tiny arc in the dim light with pupils dilated. Need to find some cheater lenses so I can see. DUH!

Then I grabbed a steel filler rod and played with dipping in the puddle. It sure didn't act like it did on Jody's videos. Kept trying, but puddle didn't form, or did only briefly but wouldn't fuse with the base metal. Was thinking that Jody guy is a fair dinkum welder for sure. I shoulda' got that Hobart Iron Man 190 with spool gun and stayed with what I know (MIG). This is going to be more of a challenge than I had thought. So I shut off after cooling down, turned off the gas, then looked at my work. Y'know, that piece of 14 ga sheet metal I found in the cutoff bin at the supplier sure is bright. . . no mill scale at all on it. And, now that I can see it in good light, it has a brushed apearance. I've never seen brushed mild steel. Could it be? Tried a magnet and it grabbed, but only weakly. Ok, I think I know what's going on. Ground an edge on the bench grinder and sure enough, it sparked weakly, too and it was too hard for carbon steel. 304 stainless someone dropped in the mild steel cutoff bin. DUH!

Geez, I really need to get better glasses. :(

60 Amps would be a little weak for 14 ga. so that getting a good puddle would be tough. I would dial in a little more on the panel. I usually dial in about what the tungsten can handle then use the pedal to control the final current. So for 1/16" I would go 90 or 100 amps. Being able to see is a real requirement for TIG. I have a real strong cheater lens in my helmet, and often wear reading glasses to boot! :O When I was young I was always in the habit of being real close to the weld to see the fine details and I miss that. Another good thing about using a foot pedal is that you can start the arc with super low current and wait for your eyes to acclimate to welding light without melting anything or having wire feed out like a MIG. Then when you're ready, lean in on the pedal to get the party started.

You can go ahead and practice with your stainless scraps. Just like you can use stainless filler on mild steel, you can use ER70S2 on stainless. They will fuse together nicely, just don't be surprised when it rusts. ;)

The mill scale on mild steel causes a problem on tig welds, cleaning or grinding it off will make the welds look 10 times better. That is one advantage the mig has over the tig, it will weld over mill scale good.

Ok, I wasn't using the pedal, just the button on the torch. If I should be able to get a good bead on stainless, I'll bump up the current and give it another try. Just want to get some practice.

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Originally Posted by Slartybartfa

Ok, I wasn't using the pedal, just the button on the torch. If I should be able to get a good bead on stainless, I'll bump up the current and give it another try. Just want to get some practice.

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I would really recommend using the pedal. You will learn faster, what the effects of too much and too little current are. At first glance you might think it complicates things, but in actuality it makes the welding such simpler. You will not be confined to one travel speed and you can really learn a lot more. After that you can go to a torch switch, and you will know right away if you have the current set right. Right now you are guessing. Think of it like this. Which is easier, setting your car's gas pedal to what you think will be 65 MPH while the engine is off, then starting it up and seeing how fast it goes? Or just pressing on the pedal while driving until you hit 65? Not to mention that you can make adjustments for hills and things.