TIG welding

Hi Geoff, looking at your photographs I can see that the end of your tungsten is blunt. You must keep a sharp long taper on the point for accurate positioning of the arc. If it's blunt the arc wanders and you end up with a poor finish.

Brian

Edited By Boiler Bri on 29/04/2015 17:02:15

Bet she's hellish knitting an Aran Sweater!

On another note, interesting that quite a lot of people here are knowledgeable about the dangers of Tungsten. The government are actually considering replacing lead shot with Tungsten Matrix. (or they were, maybe someone has passed them a note by now).

graham.

Another point, no pun intended, when grinding tungsten's try not use the grinding wheels you use for other stuff as it may well contaminate the tungsten.

Brian,

That photo was at the end of a run, and I did dip as previously mentioned, but do grind as soon as that happens.

Have only used a tungsten like that once, just to see what happens.

Bob,

I'm using the side of my wheel for now, until I rig up something with a diamond wheel. Not ideal, but that's all I've got right now. Maybe a cheapy grinder and diamond disc.

Hadmut on the MIGwelding Forum **LINK** has gone into production making a purpose built head for attaching to a Dremel battery drill, for grinding tungtens at different angles. Very ingenious, and as a result he's been inundated with orders from those working on-site that have no access to a grinder.

This devise not beyond the ability of most of us I would have thought.

Geoff - Even experts are not immune to dipping

OK so decided to dip me tungsten in, in a manner of speaking.

Done loads of TiG but it's always been top end, high amps working to sploge a broken foot on an electric motor / pump / gearbox  [ delete as necessary ]

So today and in all fairness had this bit kicking around for a week or so decided to try tigging this up.

It's a simple belt guard for a machine made out of new 18G steel sheet, precut to size in 3 pieces and requires two bends to make the cover. Unfortunately had no spare material to play with after buying this in so had to dive in.

Smallest tungsten I had 1.6mm White so Zirconiated, small cup and set to 25 amps. That was a bad mistake and had to drop to 14 amps as no way can I move that fast.

Sorry camera phone and probably wants a clean.

Close up.

Job finished and a quick clean up with flap wheel then a file and nice radiused corners and over to the spray shop.

Genuine first time I have welded this thin with TiG, in fact didn't even know how low it went on amps and this is one of those cheap crappy Chinese welders that everyone says are rubbish ?

I do know the Murex won't go that low.

Edited By John Stevenson on 11/05/2015 23:22:14

Geoff sorry I have only just read your reply. I did not read all the post. If you dip in then you must change but you have already worked that out.

With practice you will be able to control the arc and the direction of it. Most units add more amps as the arc widens to keep the current flowing and stop the arc breaking. This is a steady hand operation!

One thing that is a great help is to use a good quality visor. I bought an automatic one from screw fix as I had left mine at the workshop when I was on site, initially it was ok but as time moved on it started to flash bright and dull as I was welding. I changed the batteries but it stayed the same. In the end I went back to a fixed glass type with a flip down action. Much better in my opinion.

I like to be able to see the pool of metal swirling as I move along the seam of the weld.

If you are welding thin metal, 1mm the joint must be a good fit, if so you can just fuse the two edges together. If the metal is thicker, you will need to fill it in with a filler rod. The travel of weld will depend on how easy you find it to do? Something that comes with practice. I am fortunate as I learned to weld with oxy, acetylene and rods. So moving to tig was an easy jump. Saying that, I still hold my breath when welding and find I am gasping for air by the time I have done 4" of weld😳 Never worked out why I hold my breath, it just happens.

Brian

Brian,

I was brought up using oxy/acet as Dad used it at home, so was always using it myself.

Am finding as you, that the technique is Xferable and I too have found myself holding my breath without realising, as I did with gas I think it's because the puddle is comparably small with breathing making one 'wobble' at the wrong time. How those guys can talk and weld at the same time beats me, but I CAN whilst driving, tell a passenger what's going on round me and what I intend doing ala Tiff Needell.

Haven't got round to fuse welding butt joins yet, but did many using gas, so that experience should come back quickly, as did feeding the TIG rod.

Definitely need to experiment with power settings on thin material. I'm blowing holes as I did with gas when I first started.

Geoff - One roof sheet back up, second one now with luck.

Geoff I think you are getting too anxious as we all do with something new. Get as comfortable as possible sit on a stool so as your centre of gravity is low, clamp the work so that it can't move and use your free hand to help guide the other. This unless you are using a hand held mask... In which case change it and you can become more stable using your free hand to balance.

You can tell me off now Geoff granny sucking eggs and all that...

Jesse.

Echoing what has already been said. Comfort essential. If you feel yourself getting out of position, stop and adjust. Set up is very important. One can spend an hour setting up for five minutes of welding.

I tend to use lanthanated tungstens for everything, pretty much general purpose. A lot of the tig units out there (Sealey and the like) come with the small 1.2mm tungstens. Treat yourself to some 2.5 mm ones and collets to go with them. Also I'd definitely consider a gas lens. A decent, comfortable, ergonomic torch is a must.

If you can afford it, pulse tig is a good way to go. Really focusses the arc and allows for welding right up to or along an edge with no run away. Variable frequency is also useful for welding aluminium on AC. I've recently been welding some 316L stainless hydraulic tubing together:-

I was interested in the earlier post that I think stated using an argon/hydrogen mix for TIG brazing. I've tried TIG brazing with SIFsilbronze without much success. The SIF tips site doesn't mention using anything other than straight argon. Has anyone had any real success with it? It continues to elude me so I'd be genuinely intrigued.

Carl.

Carl,

Regularly use it for repairing cast iron castings.

Pump housing where half the casting had snapped off because it was running on only a couple of very loose bolts.

Built up with TiG braze using normal gas 1/8" sifbronze rods [ because I had them ] on DC but no idea what settings. Then drilled on on the mill as opposed to a drilling machine so I know where the hole is going, then helicoiled to get a good thread.

When your doing thin sheet,

1. You can tip it at 45 degrees and run down hill, the molten pool follow you and you can go down really fast, trouble is you get distortion.

2. Use a lot of heat sinks close to the weld, not always on the top but clamped below etc.

3. Clamp your work to the biggest piece of metal you have and then weld it, tig is local heat and very hot hot so you can get good fusion and good heat dissipation.

4. Get plenty of tacks along the joint to stop it opening up as your welding progresses along the joint, even down to 10mm spacing 3/8" for us old boys😀

Hope this helps

Brian

Carl - I've only used straight argon myself and didn't have any problem with TIG brazing. I used he SifSilCopper which is basically copper with a small trace of silicon and it was almost fun.

For industrial scale "bright brazing" you might tend to use a reducing atmosphere (argon with some hydrogen) but I can't imagine it would make much difference for the likes of us.

What was your problem? Could you describe or show what it looked like? I wonder if you simply didn't get it hot enough or hadn't cleaned it sufficiently.

Murray

I fabricated and Tig welded this fuel tank at home a few days ago. It is for a 1946 AEC bus, a vacuum is created in this tank which then draws fuel from the large main tank that I made at work a while ago. The welding set I used for this tank is a low priced Giant branded 200 amp single phase DC Tig Inverter.

This welder with the old and badly scorched shroud has done prolonged cast iron welding repairs on a full size steam roller, using nickel iron electrodes as filler rods with the welder in Tig mode.

"I was interested in the earlier post that I think stated using an argon/hydrogen mix for TIG brazing"

Hydrogin??? Has Helium become outdated? Had to get some foot operated switches for my mob of welders, easier to use on production tigging when seated. Repetition pipework fabrications.

Regards Ian.

Thank you John and Muzzer for your replies.

I shall look out the trial pieces I did to test tig brazing later today and post them. I was trying to braze together 316L hydraulic tube, the same as shown in the photo in my post. The photo shows the tubes after I tig welded them with 308L filler wire.

I think the tubes were clean enough and I'm not sure about the heat...I was concious of not getting to the stage where the base metal was beginning to melt. I think I might be able to use pulse settings to good advantage in the brazing application. Hopefully with your advice I can get to the bottom of where I am going wrong, as I would like to add tig brazing to my arsenal of techniques.

Ian..I believe that TIg started out with helium and indeed was called "heliarc". I have been wanting to try tig welding with helium for some time. My local gas supplier doesn't do helium, so I'll have to pay a visit to the large one a few more miles away in the near future.

Kind Regards,

Carl.

The only similarity between hydrogen and helium here is that they both have very low atomic weights. Helium, like argon is totally inert for the purposes of welding.

Helium is often mixed with or substituted for argon in TIG welding as it gives a higher arc voltage and thus affects (increases) the penetration. In the US where TIG welding was invented, large volumes of helium were accumulated as a byproduct of natural gas production there. For our purposes, most of us are going to be fine welding with whatever is cheapest and most readily available ie argon.

The use of hydrogen is quite different. It is not inert - in fact it is a reducing agent - which means that it will clean off oxidation in the weld area. A few decades ago, neat hydrogen or water gas would be commonly used for induction brazing but more recently, an inert shielding gas of argon with a few % of hydrogen would be preferred for brazing. At those concentrations, there is no danger of explosion but still the beneficial self-cleaning effects.

As I said above, I doubt any of us here would need or benefit from argon-hydrogen and in my own experience, pure argon TIG brazing works well if you prepare the surfaces carefully. Unlike carbon arc and flame brazing, you don't need messy fluxes. All you need to do is obtain some Sifsilcopper or similar rods and get cracking. If you can solder, you shouldn't have a problem TIG brazing, it's that simple.

Murray

Yes Carl, I know about Heliarc, that's why I questioned Hydrogen. Thanks for explanation Murray. Heard about Hydrogen generators used for Jewellery and small scale precision welding but didn't know about large scale.

Regards Ian.

Hi Ian and Muzzer,

Thanks for the interesting posts, particularly the origins of heliarc. I knew that tig was invented in the US, but what I didn't know was that the helium was sitting around as a by product of another process. A similar thing happened in rocketry with furfural alcohol. I've been using argon for a long time in my tig set up, but I just want to try helium to see the difference.

I was obviously doing something fundamentally wrong when I tried tig brazing, because what I ended up with looked like a bird had crapped on my work. I have been soldering since I was 11, so hopefully I should be able to get the hang of tig brazing!

Kind Regards,

Carl.

Those examples of welding I put up by my girlfriend were done with Heliarc when she was in the States. She built her own aircraft from a set of plans, not a kit and because of this had to become a coded welder to achieve this.

As I say she is quite shy and doesn't like to brag so I do it for her

I feel out of place amongst you expert welders. But have a query, I bought some things at an auction as I was picking thing up the porter said that is included, I have123 1.6 mm Silicon Bronze welding rods. What are they useful for ?. I also have a Mig welder and one of those electronic welding helmets, which also came with the rods and a hand held type which I have used for stick welding. I find that I have difficulties seeing when using the electronic helmet when using the Mig, but Ok with the hand held, but that is not so convenient. I have played around with the controls on the electronic, but to me its still too dark when used on Mig I wander all over the place, OK on stick. Is it me, any kind suggestions please.