TIG Welding

Welding

Valerie,
Thanks for the new forum. May latest project is all mild steel .065 tubing. I had lots of problems with pitting in the welds. I tig welded it using straight argon. I cleaned the tubing with denatured alchohol. It's been a few as in 4 or 5 years since I have done any tig. I have been mostly using mig as of late.

Any ideas?


Valerie Rock's picture

pitting in steel weld

TIG welds are beautiful when everything works right! Here are some things to check to solve the problem!

The alcohol cleans off any grease but not the oxides on the surface. You need to remove the oxides with emery cloth or some other abrasive. And if the end of the tube has a burr when it was cut, scrape off the burr with a carbide scraper. Oxides and cutting fluid can be left there. Also when you wipe on/off the alcohol, the cloth leaves bits of material on the burr. This can make pitting too. Clean inside and outside the tube to at least a 1/2" on either side of weld.

IF you are welding the steel with no filler rod, it is especially important to remove the oxides before welding. Filler rod material has deoxidizer in it (ER70S-6 used for oxyfuel is also used for TIG and has high silicon to deoxidize and make the weld pool more fluid).

With this thin wall, you are probably not using filler.

Other things to check:
If there are loose connections or pin holes in shield gas lines, air will aspirate into the line.
Make sure the torch angle is not too flat (should be 18-20 degrees off the vertical) and it is not too far from the metal.

The tungsten stick out (from the cup) should not be more than the internal diameter of the cup (unless you have a gas lens, which is like a screen or faucet washer in cup). If angle or stick out are excessive, the weld pool is not protected from the atmosphere.

Rarely, but it is possible: the argon in the cylinder can be contaminated. Don't pounce on this as your first possible cause. But if your shield gas supplier does not adequately purge the lines between mixing shield gas (such as the 75-25 argon Co2 mix for MIG), there won't be 100% argon.

Of course, the tungsten needs to be ground of any contamination from previous welding foibles, and the machine set for DCEN and a high frequency start so you do not have to scratch start the arc.

Let me know which one of these fixes the problem or if it is something outside of this list!


Emfairmeadows's picture

Thanks for that post Valerie

Wow Valerie,
Thank you for that VERY informative post. Perhaps we should convince you to write a book on welding practices and troubleshooting for the metal artist. I plan to print out your responses and save them until I buy a TIG welder.

Elizabeth M. Meadows
Mother, Metal Sculptor in that order.

"Gotta love a gal with an anvil."
-Buffy Summers (Buffy the Vampire Slayer)


Rick Crawford's picture

excellent reply

Hey Valerie -

That was an excellent reply.  I learned from it and am glad it is here to be kept for all of us to see it.  I can see we have a knowledgable host on this group.

Thanks for starting it and answering questions.

I have used the burr on the cut end of the steel for the filler before.  It was there and easier than cutting it off, then using a filler rod.  I can see, however that if you are having trouble with pinholes that it should come off to eliminate one source of problems.

|8^)>

Rick Crawford at Smoky Forge


browbrew's picture

Thanks Valerie, My first

Thanks Valerie,
My first guess would be that there was still some cutting fluid inside the tubes. I cleaned it all then wire brush with a stainless brush. So I do not think it was rag fuzzy bits. I have brushes for each type of metal clearly marked.

I'll run some tests before I start the next project. Although you know they will work perfectly it won't be until I'm working on an actual project that I'll have a problem. ;-)

-gary

www.earthtravel.net/gardengates


Metal Momma's picture

My welding nephew said that

My welding nephew said that I should learn to just TIG weld and I'd love it - it sounds like lots and lots of practice are required..... So I'll make sure to keep watch on this blog and maybe try it someday.

Metal Momma - metal art everlasting


Valerie Rock's picture

TIG overview

TIG stands for Tungsten Inert Gas. Another common name for it is Heli-Arc, which is really a brand-name at this point.

TIG may be compared to gas welding but using electricity. The heat source is an electric arc off of a rod of tungsten. The tungsten is held within a copper collet in the torch body. The tungsten is considered a non-consumable electrode. This means that it is not used up in the welding process.

An inert gas (Argon or Helium) is provided by the torch in order to cover the molten weld pool. This protects the molten metal from contamination by the atmosphere.

The power source used is normally set for DCEN (Direct Current, Electrode Negative) to weld all metals except Aluminum. Aluminum used AC (alternating current).

Filler rod may or may not be added, depending upon the type of joint and the thickness or the metal. The filler rod is usually one that matches the base metal in composition and strength. But there are some applications in which the filler rod needs to differ from the base metal to obtain an optimum weld. (an example would be the different types of aluminum: 1XXX aluminiums area best welded with 4043 rod)

Most power sources use a foot pedal or thumb switch to provide variable amperage (heat) while welding. Similar to the gas pedal on an automobile, this pedal or switch allows the welder real-time control of the amperage needed. It's great!

The technique used to do the welding is similar to that of oxyfuel welding. The torch provides the heat and the filler rod is added by the welder into the molten puddle. In TIG, however, the torch angle is about 20 degrees off of the vertical (oyfuel it is 45 degrees). And the filler rod is added pretty much flat, almost parallel to the base metal.

TIG takes more manual skill to master than the other welding processes. But the welds are of extreme high quality: there is no splatter, smoke, slag.

This process is great for bronze castings, stainless steel, aluminum, titanium, tool steels.


scrollerbear's picture

thin metal

Valerie,

I have never used a TIG welder and I work mostly in thin sheet metal. Is it possible to weld aluminum as thin as .032 or cold rolled steel in the .024 thickness with an inverter TIG? The only welder I possess at the moment is a tack welder and propane/oxygen torch. I use a lot of rivets!

I must sound like the dummy I am but would appreciate any info.

Mark


Gene Olson's picture

al.

You need AC and hi frequency start to weld aluminum with a tig.
Yes you can weld that .032 metal

You can also weld it with an oxy acetylene rig and very small tips, or oxy Hydrogen (though I haven't tried the latter)

If you want to learn that, go over to metalmeet.com and see if you can get to a metalmeet near you.
There may be somebody willing to share some hands on help.

Gene Olson
Sculptor
Elk River, MN


scrollerbear's picture

Thanks Gene,

Thanks Gene,

I have been told the learning curve is a little steeper for tig welding thin aluminum but I have lots of time. Of course I will probably have to settle for a cheap (no doubt cheaply made) machine for now. I really need to make a major sale.

Mark


Gene Olson's picture

So buy a raffle ticket for

So buy a raffle ticket for the Metalmeet Miller syncrowave fund raiser.
$5.

Lightning could strike.

Gene Olson
Sculptor
Elk River, MN


NELSON's picture

WELDIN TIPS

Hi Valerie: It`s nice to have people like you on this site.
Unexperience guys greatly appreciate technical advise. Can I do Tig welding outdoors? And do you have any experience with Flame Metal Spraying? If so, any brand you may recomend. I want to buy a Flame spray gun. Thanks for your help. Nelson.


visitor's picture

can i tig weld outdoors

Yes you can but there needs to be some sort of shield to keep any wind or breeze from blowing the shielding gas away from the weld puddle or cool the fresh weld bead to fast and sometimes there is more of a draft than you think


Valerie Rock's picture

TIG TIPS-specific to mild steel

jballcorn@gmail.com wrote:

Hi Valerie, I'm James in Paris, TX my tungsten seems to start oxidizing almost immediately after striking an arc, starts wandering around, etc. All help appreciated. Thanks.
I'm trying to get better at TIG, and am asking a few techie questions,
with SPECIFIC REFERENCE to MILD STEEL TIG WELDING.

1. Current and Polarity: DCEN (Direct Current, Electrode Negative). AC is used for aluminum.

2. Tungsten? 2% Thoriated is fine. Lanthanated or Ceriated may be used. You’ll find that the Thoriated may be phased out in next few years because it is low-level radioactive.

3. Tungsten diameter? Depends upon the thickness of metal to be welded. We use 3/32” dia for most all the metal thicknesses. But if you are always welding thin steel like 18 gauge and less, a 1/16” may be used. Need a smaller collet too.

4. Amperage range? Depends upon the metal thickness. 16 gauge mild steel can be 35-45 amps.

4a. How much do you increase amperage with finger/foot control? The remote adjustment of amperage makes it easy to modify the puddle size as you weld. Some people like to adjust the machine so that the foot pedal works as an on/off switch….(Current set at panel). Others like to adjust machine so that when the pedal is all the way down, it is the top amperage used. This way, you can keep the amperage the same while you are welding. The reason for using a variable amperage is so you can taper off the amperage at the end of the puddle as you move a little ways backwards over the weld. If you do this, you don’t get that little pinhole that shows at the crater end.

5. Argon flow rate? Yes, 15 CFH (cubic feet per hour) and of course you need to adjust this while the argon is flowing through the torch. I use 15-20 cfh. And if you are using a very narrow cup or a very wide cup, you can tell that it takes more or less to flood the weld area with argon. Too high for a narrow cup will cause turbulence in the area and make contamination possible.

6. Touch start or hi frequency arc start? Some new machines have a lift arc feature. Without the arc started, you touch the metal with the tungsten, back off and the machine senses the voltage difference and initiates the arc.
But, with most all machines, it is called Spark-Start Only, or high frequency start-only (not set in the high frequency continuous or “ON”-this is only used with AC)

7. Do you use a deoxidized filler metal or just plain mild steel filler metal?
A mild steel filler rod with a high number at the end. Example: ER70S-6. Has good deoxidizing properties and will increase the fluidity of the puddle. See the reply to Gary on that first post at ArtMetal-Welding group.
You can also use a stainless filler like a 308L.

8. You said you had a problem with : tungsten (thoriated) tends to oxidize soon after start welding, it acts much like an ox/ac flame that is "oxidizing". Plus, the arc is erratic, wandering here and about. I use a pointed tip, ground on a "tungsten only" grinding wheel.

Check the current and polarity.
Check that there are no loose fittings or pin holes in the gas hoses.
If the base metal is heavily oxidized (rusty) you need to clean it off w/ abrasive
If base metal is greasy or has cutting fluid on it, need to clean w/ solvent
If filler metal is rusty, greasy or if your gloves are greasy…clean, replace.

Tungsten should be ground clean of any contamination from base metal or filler. Then a small flat should be ground on the end. Then grind to a point, similar to a pencil point but a little “stubbier”. The grinding marks should go lengthwise…not across. This means you have to grind with the tungsten pointed upwards on the grinding wheel. This is opposite all the safety rules you have been told….so do not stand with leg or crotch in line with the tungsten! A small flat should be left at the tip of the tungsten. When looking for it, it looks reflective…This is so if you do touch the tungsten to base metal, it has less chance of sticking, arcing, and leaving a broken off piece in base metal …and irregular tip on tungsten.

When adding the filler metal to the puddle, add it at an angle fairly flat or even with the base metal. Keep it close to the area you are welding so that it does not get out of the argon “bubble”. Otherwise, it gets oxidized when it is hot…and then you are trying to add the oxides into the pool…

If filler is added at too steep an angle, it can pull the air down into the pool…as in a venturi effect.

EXPERIMENT on scrap metal and get settings, weld quality as you wish before welding on the actual part. Remember to have a good ground connection. If the part to be welded is lying on a table top that is grounded, make sure that the part is actually touching the table in more than just a point/small area.

I will put up illustrations within these posts (soon) to make them more readable! Persevere! Like driving a stick-shift car, all of a sudden it is so much easier!

~VRocK


visitor's picture

clean your metal with a

clean your metal with a grinder. metal must be clean down to new metal.


jolly roger's picture

after grinding

If you use a grinder on your metal always take a wire wheel to it afterward. Removes any contamination from the grinder residue. Make sure it is a clean wheel, no grease, rust, etc. I use strictly stainless wheels. They are not that much more expensive, and are a tax deduction anyway.


Matt Weber's picture

With rare exception, I Tig

With rare exception, I Tig weld exclusively everyday. And everything from mild steel to copper and bronze. When I first started to learn how to Tig weld, porosity was a big problem and was very frustrating. No matter what I did (cleaning, grinding, acetone, etc) same results. Once I got my welder set up correctly (gas pressure, cup size, etc) the porosity stopped. Cold. I honestly can not remember the last weld I made that had any type of porosity in it. And, I never clean, grind, or use solvent on anything prior to welding. I weld right through mill scale probably everyday with the same results. I would clean up rusted steel if I had a reason to weld it though.

I'm not saying that clean metal is not important or not your problem, but in my experiences its most likely your set up.

Valarie posted some excellent suggestions related to torch and regulator set up and I would read them thoroughly. I use a CK torch with a gas saver lens that's advertised to save gas and disperse a wider, smoother barrier of shielding gas. I never payed too much attention as to the gas savings, but like I said, porosity is something I don't think about anymore.

Tig is always frustrating at first. Hang in there. My mig just sits and collects dust now...


geb's picture

Interesting thread! I'd

Interesting thread! I'd been messing with tig at a couple of factorys I worked in for years and always wanted to get one of my own for art and furniture design.
This is a long post, but I wanted to share it with a few of you who are considering adding a tig to your shop.

I researched for about three solid months and finally made the leap with this one...
http://www.asedeals.com/firepower_tig.html
Price sometimes fluctuates. I got it for 1899.00 earlier this summer. I just checked the web again and found this link...
http://www.weldingsuppliesfromioc.com/servlet/the-1633/THERMAL-ARC--TIG/Detail

It's neck and neck with comparable Miller and Lincoln units, and is shipped with everything you need to weld except filler rod, a helmet, and a bottle of gas. By the time you add the cost of pedal, torch, stick holder, ground cable/clamp, gas gauges/hoses, cups and starter set of tungstens, and a few other assorteds to other inverters, the savings is just about 50percent over the bigger names.

This is a Thermadyne ArcMaster 185. Firepower (pictured at ASE website) is a rebrand of the same unit, but the one that got delivered to my door was an ArcMaster. Everyone I talked to on various welding forums received the Arcmaster branded unit as well from this vendor. Don't think it makes a difference. Merc Sable or Ford Taurus kind of thing. It looks like that second link I gave has the ArcMaster unit pictured anyway.

It's designed/manufactured in Japan by Sanrex. Sanrex supplies many of the electronic components for other brands of inverter tigs out there. The Japanese are as near to the state of this art as it gets. There is really no reason to spend more on the red or blue machines unless perhaps you find comfort in a larger community of users. I've been using this machine for three months now and couldn't be happier. (the Miller inverter is nicer looking, but what the heck)

I got a twenty dollar helmet from Menards to last me a year until I decide on an autodarkener. The No.3 80CU argon tank cost me 150 dollars with free first fill at a local supplier (another good deal) and the filler rod is really suprisingly inexpensive. I replaced my old gloves with a good quality ten dollar pair. I probably weld about half hour daily on average. Gas is 45 dollars per fill and I've done it twice now. I'm happy that my electric bill hasn't taken a hit. I was a little worried about that, but it's not even noticeable.

I learned on a couple of Miller Syncrowave 250 transformer based machines. I was afraid that I'd been spoiled by the power of the bigger machine but the inverter really suprises me.

I'm honestly not a rep for these things. I'm just pretty pleased with the one I got. There's a beefier version called an ArcMaster 300 but it's much more expensive. There's also a 200 in the series, but the thermadyne tech assistance guys told me that it's essentially a 185 capable of variable voltage and three phase. The 185 is 220v single phase only so it needs a suitable outlet installed in your shop. The Miller dynasty 200 is able to run on 110 if that's important to you.

I was VERY tempted by some of the Chinese inverters I saw on Ebay, especially some of those tig/plasma cutter combos. Almost half the price, with plasma cutter basically thrown in! I don't know. I agonized over the decision at the time, but now that the money is "sunk" I'm relieved that I decided to go with a proven company. Whenever some little electronic gadget breaks down and frustrates me now, I look at my welder and imagine how heartsick I'd be if I'd gone budget with it and perhaps been stuck with trouble.

I could be wrong. There's plenty of anecdotal horror associated with the Chinese welders, but there's also a lot of general anecdotal horror (most often either cynically apocryphal or just plain ignorant) associated with anything foreign in this strange political atmosphere, so you just have to sift through it with an open mind.

Anyway, I just wanted to lend a little from my learning curve on this one. I wanted one of these for many years.
They really do add many more dimensions to work and art.


John Hampton's picture

TIG Welding

I think there are some very good suggestions being offered in this forum. Hoo Ray for ArtMetal !!! Contributions from fellow weldors are always sought after and appreciated by novices such as myself. I have a Lincoln Square Wave 175 that does a nice job on steel and aluminum but I'm having problems with brass. The zinc in the castings tends to vaporize before fusion takes place. I have followed practically all the parameters in the GTAW manual, but without any sucess. I suspect the filler rod (silicon bronze)although it works fine for brazing the brass connections with OXY/ACET process. Any suggestions as to what I am doing wrong? Fortunately , I've been using scrap brass to practice on. John Hampton.


visitor's picture

tig welding

preheat the brass so that it is not necessary to apply so much heat to it with the welder this will help with the zinc vaporizing


Rob Sigafoos's picture

FYI- Northern Tool has an

FYI-
Northern Tool has an auto-darkening, adjustable intensity helmet for $50.00. We have two that we have been using for a year+, (MIG, TIG) works great.
Rob


mele miller's picture

Yeah! I got that helmet to

Yeah! I got that helmet to and it works great. I'm not sure why you need to spend 200 to 300 on a helmet.


Rich Waugh's picture

Mele, The reason for

Mele,

The reason for spending the big bucks for something like a Jackson NexGen helmet is that the high-dollar ones have more sensors, greater adjustability, and generally work better. Particularly if you're doing low-current TIG welding, those four sensors really help to keep you from getting "flashed." With my cheapo auto helmet, I would get flashed once in a while if my head was in a weird position where the sensor couldn't see the arc but my eyes could. That never has happened with the NexGen. It has also survived several drops, something that the cheapo only did once - second time killed it. Lastly, the NexGen (and others, I just happen to have a NexGen), has a replaceable battery for backup, land the cheapos mostly only have the solar. When the battery goes, they're done.

That all said, for most people, I think the cheapos work just dandy. They're all fast enough on the switching, and almost all of them default to dark if something goes wrong with them.


visitor's picture

Auto lens welding hoods

I too have a NexGen lens. I like the 4 corner sensors but mostly got it for the larger lens. The one thing I don't like is the weight, especially with the magnifying lens I have in it. Lastly, what ever works for ya, go for it.........

John Dach


Rich Waugh's picture

It's interesting thatthis

It's interesting thatthis came up when it did. Today I was doing some welding and managed to miss the hook when hanging up the NexGen between welds and it hit the floor, with the innard flying everywhere. I was in kind of a hurry, so I scooped up the parts and set them aside to assemble later, and grabbed my HF cheapie helmet. Sure enough, that thing was dead, with no way to replace the batteries.

I went ahead and put the NexGen back together and it was fine, and I stuck the HF helmet in direct sunlight to see if it would charge up the batteries. No go. Another cheapie bites the dust.

I'll probably replace it, since I like to have a backup and a helmet for on-site work where theft/breakage is a possibility, as well as having a second helmet for the rare occasion when I have someone helping hold stuff. (I don't like to trust a helper to have the trained reflex to flip a helmet down,and the auto helmets are great for that.) This time though, I'll try to find a cheapie that has a replaceable back-up battery, since that helmet sits around unused 90% of the time and won't be getting charged from arc flash or sunlight.


visitor's picture

shade value for plasma cutting

Does any one know if a regular set of oxy-acetylene glasses can be safely used for plasma cutting or does that require a shade 9-10 helmet?
Brian Davis


visitor's picture

I would suggest at least a

I would suggest at least a shade 7-8. In my experience shade 5 wasn't nearly enough, however a shade 9 can sometimes be too dark if your using a drag tip and free handing. It's hard to see the line your tracing. If your using a machine tip a shade 9 works ok.

Jake


ArtsApart's picture

porosity

if your welding surface is clean then pitting is normally caused by lack of shield gas turn up your regulator and get more gas flowing
ArtsApart.co.uk
Quality Contemporary Wall Mounted and Floor Standing Sculpture


visitor's picture

electrical parameters.

Is anyone can help me to find the electrical parameters of ER70S-6. I been browsing many time but only the amphere is given? i am doing my WPS right now.
I hope anyone can help me.

rey


sail4evr's picture

TIg welding tubing

Hi, I'm a newbie at this. What is the smallest (least expensive) TIG machine that can do an adequate job with 1" thinwall (schedule 5) ss tubing.
Does smaller or less expensive mean more difficult or longer learning curve?
thanks,
joe


Rich Waugh's picture

The least expensive TIG

The least expensive TIG machine for that sort of work is going to be one of the Chinese inverter TIG machines, I'd guess. I you never plan on doing aluminum you an get b with a straight DC TIG machine, but if you think you might someday want to do aluminum welding you would need a machine capable of using AC as well as DC.

I have a Chinese inverter TIG that I bought from Longevity Inc. and I've been generally pleased with it. A simple DC machine like this one would do your tubing just fine. 

Yes, thinner stock is sometimes more difficult to work with.  Your 1" thinwall tubing shouldn't be too bad, though.