TIG welding

[John Stevenson 1Participant @johnstevenson1]

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.

[Boiler BriParticipant @boilerbri]

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

[MuzzerParticipant @muzzer]

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

[LathejackParticipant @lathejack]

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.

[CirclipParticipant @circlip]

"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 Has Helium become outdated?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.

[Carl Wilson 4Participant @carlwilson4]

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.

[MuzzerParticipant @muzzer]

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

[CirclipParticipant @circlip]

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.

[Carl Wilson 4Participant @carlwilson4]

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.

[John Stevenson 1Participant @johnstevenson1]

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

[john fletcher 1Participant @johnfletcher1]

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.

[MuzzerParticipant @muzzer]

One of the problems with some of the cheaper auto darkening helmets is that they don't go very clear when there is no arc and you often can't turn down the darkness enough when it is dark. I really struggled to see what I was doing with my first Xmas Cracker helmet and finally forked out a bit more on a proper Miller helmet, then a Lincoln one which didn't need to be manually turned on before use each time. Once I had the Miller, I also realised that in fact the crappy one wasn't darkening evenly and consistently across the whole lens and I couldn't turn it down far enough to see properly either.

I would recommend using a light to illuminate the work so you can get things lined up before striking the arc. Although the auto darkening feature is triggered by the light of the arc, they can tolerate a fair bit of illumination before that happens. It's also worth getting a large lens – the larger the better. And get the helmet close to the action so you get a really good view. It's even more important to get a good helmet for TIG, as there is a lot more to get right. MIG is more like a hot glue gun.

The other issue I had was due to the reduced range of vision we suffer from when we get into our late 40s. This prevents us seeing things that are close without reading glasses – or looking downwards through varifocals if you already wear glasses. The ideal viewing distance for me seemed to be closer than I could focus when looking forwards through my varifocal glasses. The varifocal feature wasn't much use, as you don't tend to weld with your eyes pointing downwards, which is how they work. However, you can buy magnifying lenses from most of the major helmet suppliers. These clip in behind the window and allow you to see what is going on. Definitely recommended.

Murray

[andrew winksParticipant @andrewwinks64215]

Good idea re the magnifying lenses, Murray. After many years of using the standard helmets, I finally lashed out on a auto darkener…what a revelation. Had to get a level of trust going though, will it darken as required or will I cop a all too familiar grit in eyes syndrome of a welding flash….I still tend to squint when striking an arc as a precaution! Andrew

[WindyParticipant @windy30762]

Years ago when Mig welding chassi repairs sometimes when working in a shaded area the auto darkening could be slow and arc eye was the result.

Paul.

[OuBallieParticipant @ouballie]

Jesse,

I will never ever complain about receiving advise or help.

Not having done any gas welding for so long, I think it's frustration creeping in at not getting it right immediately.

I need to make one of those weighted pointy hold-down doodabs to stop the practice pieces getting away.

Now that the Carport roof appears to be staying put in the present near gale force winds, leaks cured, and once the floor paint has dried, I will be back practicing.

Need to get the basics right before tackling on-car welds, but thankfully not many of those.

Thanks to all for the advice shared.

Geoff – Yesterday just managed in time, to stop GD from walking on the wet paint. Whew!

[Nick HughesParticipant @nickhughes97026]

Right,lets just dispel the myth that you'll get "Arc Eye" if the lens fails to Auto Darken, you won't!

For the same reason that you won't get a suntan when sunbathing behind glass, The UV rays are absorbed/blocked by the glass/lens in it's "Clear" mode

You can get the Dazzled blind spot from the arc brightness (that gives a good excuse for a brew while is passes), but not true UV (Sunburn) damage to the eye surface.

True "Arc Eye" when using an Auto helmet comes from the UV getting reflected back into the helmet from behind (passed your head), e.g.from light coloured workshop walls and low ceilings.

Nick.

Edited By Nick Hughes on 05/05/2015 14:54:04

[nigel jones 5Participant @nigeljones5]

Nick – agreed if you buy good quality unit, but with the rubbish on ebay for under £50 you would have to be bonkers to trust it against UV and IR. Might be ok for 3 seconds at 80 amps but I got a 3am wake up call using one such unit, so never again!

[Involute CurveParticipant @involutecurve]

This is an example of Tig brazing at its best, Sifbronze make a rod just for this…. I wish I could say it was my work but its not…

Edited By Involute Curve on 05/05/2015 16:32:43

[Jesse Hancock 1Participant @jessehancock1]

It seems a shame to cover it up. Very professional.

[Neil WyattModerator @neilwyatt]

Blimey! That's almost a work of art!

Neil

[Involute CurveParticipant @involutecurve]

I think its Sifbronze No 32 if I remember correctly, specifically for use with Tig brazing.

Shaun

[andrew winksParticipant @andrewwinks64215]

That's interesting Nick, I purchased my "lid" from a welding supply store but that does not necessarily mean than it's prime quality other than the fact that I asked for a good quality unit. Will need to double check that it's got the UV filter in the clear mode as your described. Cheers, Andrew

[clogsParticipant @clogs]

Hi all, now for the stupid question.

Any recommends as to a AC /DC tig machine, mostly for St St and ally once competent…..

I also need to make a frame and girder forks for a 30's Indian 4 ……

Can gas, arc and mig with the best of them…..it won't be used everyday or to earn a living..

I just want something 1/2 decent..with a foot pedal…..but a £1000 squids is out of the question, a TIG is pure luxury and still have to get it passed by her-in-doors….hahaha…..

Or just forget it…..

If I could get 1/2 as good as Involute Curves photo's b well happy…..

As for my frame, didn't quite fancy gas brazing such thing, banana's come to mind…

Always scared of fle-bay…..I did look into it a few years ago but the price then was over £2,000…..Any help appreciated, I know it's a mine field…..

Thanks, clogs

[BowberParticipant @bowber]

Re UV protection.
There was a study years ago and they found that a £1 pair of plastic sunglasses gave just the same amount of UV protection as a £100 pair of sunglasses, so there is no reason that a cheap auto dark helmet will be worse than an expensive one before the visor goes dark. However it may not operate as quickly or as well.
My welder friend said they always wore wrap around sun glasses and used a couple of shades lighter on the visor because of the weld flashes from other welders on site.

Steve

[BowberParticipant @bowber]

That frame is lovely, my dads brazing was like that using O/A and a gas fluxer, he also used sifbronze rods. Pity I've not got any photos but it was before camera phones, in fact it was before mobile phones!

Steve

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