TIG welder

[MK1_Oz]

I bought a decent MIG welder a number of year ago and used it to build my Escort. I find myself needing to weld aluminium brackets and components from time to time and am considering my options. I could continue to get my usual engineer to weld it up (at a cost), I could get a spool gun for the Lincoln Electric MIG or I could buy a TIG welder. Although most people weld aluminium using TIG AC I have read that you can weld aluminium using DC TIG if you use helium gas. A DC TIG is much cheaper than an AC/DC TIG.

In Australia the rough costs are;

• spool gun + gas bottle ~AUD$600 (340 quid)
• DC TIG + gas ~ AUD$400 (230 quid)
• AC/DC TIG + gas ~ AUD$1400 (790 quid)
• engineer AUD$100/hour (60 quid)

I need to weld aluminium from say 1mm up to around 5-6mm. Need to weld aluminium maybe a few times a year. I assume the TIG is a worthwhile options for steel welding also?

What are your thoughts?

PS - I have never TIG welded but then I had never MIG welded when I bought the Lincoln Electric

PPS - have been reading up on this puppy https://www.ebay.com.au/itm/UNIMIG-R...wAAOSwnK9ZQLrK

[davemk1]

I have a tig which I used on my car resto.
If you can gas weld then tig is pretty much the same principle!
Never used it for aluminiun so can't really comment on that one.

[runoutofrigos]

TIG welding steel is very different from welding Aluminium. If you intend to do AC welding, I would suggest yu make sure the welder you buy has the facility for a pedal control. It makes it far easier to control the "puddle" when working at the low temperatures required for aluminium.

Like most things, practice, practice, practice.

Simon

[katana]

Never seen anyone or heard experts say DC TIG is possible with aluminium! The use of Helium mixed with Argon - 25/75 or 40/60 and AC TIG allows a hotter arc for welding thicker material with lower amperage machines. Alloy welding is hard enough using AC IMO + with just DC, you'd lose the cleaning action from the polarity reversal which is essential when welding aluminium.

[MK1_Oz]

Never seen anyone or heard experts say DC TIG is possible with aluminium!

there are a number of YouTube videos on this. I suspect that the people doing the demonstration or highly experienced welders so can more easily compensate for the difficulties.

Money being tight I suspect I will end up just out-sourcing to my engineer bloke but keep your thoughts coming.....

[Schaloupka]

Yep you can weld with DC on helium.....but honestly you get far better results with AC and 100% argon. I would strongly suggest an AC Inverter machine as suggested with a pedal as aluminium is such a great conductor if heat you need to back off the amps especially on thinner stuff so you dont blow out corners. A machine that maxes at 200 amps should be fine, just keep an eye on duty cycle though. Welding smaller stuff is okay, but once you get good at tig you'll use it on larger projects and be glad to have the extra amps and duty cycle handy.
I am no welder, but i saved and shelled out on a watercooler and ac machine...and i do not look back at all. The Everlast machines are great (Bob Moffat loves them).....but get some gas and just practise like mad.
It is really addictive when you get into the swing of it!!

[MK1_Oz]

Yes I will go with AC for ally and 200amps (cannot afford a larger machine).

The Unimig I linked to above has some bad reviews so will steer clear. I have seen Everlast but know nothing about them. Hard to make a decision when you have little knowledge in the area of purchase hence my post.

Do I need a pedal to start with? Can I learn with the torch or is it better to add the extra $ and get a pedal up front? Also, I believe TIG uses a higher gas flow rate generally than MIG??

[mick32]

most modern 200amp ac/dc inverter tig plants might have different brand graphics but nearly all share the same components internally so pick whatever brand you want ,but i would strongly suggest a foot pedal and a good high qualiy gas lens and a few days on your own and practice a lot.dont be afraid to plat around with settings and experiment and if your doing heavy aluminium ie big castings wind the hertz down below 60 for deeper penetration

[katana]

Never seen anyone or heard experts say DC TIG is possible with aluminium! The use of Helium mixed with Argon - 25/75 or 40/60 and AC TIG allows a hotter arc for welding thicker material with lower amperage machines. Alloy welding is hard enough using AC IMO + with just DC, you'd lose the cleaning action from the polarity reversal which is essential when welding aluminium.

Time to eat my words - although they were in good faith! Similar answers to above off a welding forum site but also offered the solution of using a spool gun - aluminium wire - helium as well I guess............ a self consuming electrode sounds about right but as to finish .....anyone's guess?

[davemk1]

most modern 200amp ac/dc inverter tig plants might have different brand graphics but nearly all share the same components internally so pick whatever brand you want ,but i would strongly suggest a foot pedal and a good high qualiy gas lens and a few days on your own and practice a lot.dont be afraid to plat around with settings and experiment and if your doing heavy aluminium ie big castings wind the hertz down below 60 for deeper penetration

I have a telwin technology 160 ac/dc Hf and lift start. Sealey do a machine too which is pretty much identical! I haven't used the foot pedal much but the Hf start is handy as it saves having to re-grind the electrode so much.

[stevieturbo]

Never heard of DC TIG alloy welding...but you can most certainly MIG weld aluminium, which would often require a spool gun.

But really, for flexibility and control, just buy an AC/DC TIG.

MIG/Spool

https://www.youtube.com/watch?v=tNmj-R8tIJw

[MK1_Oz]

...handy as it saves having to re-grind the electrode so much...

What is the deal with electrode grinding? Is this something that has to be done frequently? I assume you need a special tool to get angles right and prevent contamination?

[davemk1]

You just sharpen them on a regular bench grinding wheel to a shallowish angle. (more pointy if that makes sense) getting a specific angle isn't that important.
They do need to be ground a certain way so the arc comes off the end right. I can't think in words how to explain it but basically you point the electrode up the wheel as opposed to laying it flat on the tool rest.
Google or a YouTube video will explain it much better.
I just grind a few at a time so I don't have to keep getting up every time it needs redoing.
Its not important that it's always arrow sharp and you'll just know when it needs doing again as the arc will not come off the end nicely.

[katana]

Tungsten grinding - its important that the grind scratches (for want of a better word) go from rod 'body' to tip ie parallel to the tungsten and NOT around the circumference otherwise the arc will tend to wander around avoiding the tip point.

[mick32]

tungsten tip needs to be sharpish for dc welding ie stainless and various steels but when welding ac on non ferrous metals ie alu copper titanium etc you need the tungsten to ball up at the tip i usually get the tip to ball up by holding the tungsten over a lump of copper for a couple of seconds.

[MK1_Oz]

Cheers. Will look into the tip topic more....