Becky, I have an ERFI pocket TIG, which although not marketted as being capable of alloy welding was found by accident (hooking up the cables wrong polarity) that the unit would weld alloy very well indeed, OK it's not a Chinese make (German) but it was at the budget end when I bought it 15 years ago, so probably not a million miles away in similarity to your machine!
My machine doesn't have an Amps indicator either, just numbers on dials, so some experimentation is usually needed!

As you do, I use white tungstens and 7-8 on the argon, I also make sure I keep well out of any draughts from doorways or open windows!

I don't do enough alluminium welding to claim any proficiency, and much of which has been reclaiming corroded areas on alloy cylinder heads, but what I did find was that the area being welded had to be kept scrupulously clean with a stainless steel wire brush, And crucially with my machine, the weld was much easier to start and control if the metal was pre-heated with a blow torch!
If I didn't pre heat, the weld was a pig to start, and the tungten would stick itself to the metal leaving debris that had to be gouged out, ruining the weld!
Is it possible the 1mm (16G?) material you're trying to weld is cooling too fast with the heat migrating away from the seam too quickly?
Just my thoughts as your woes echo the problems I came up against!

John.

I've had great success with hts-2000 repair rods on a small sheet aluminium fabrication that I have just completed.

Take a look here It's quite an easy thing to do, once you've had a little practise and there's virtually no chance of burning through thin material.

Martin.

Hello Becky,

Hi, interesting reading this and your other posts about your mobile crane project. I have done some TIG aluminium work both in my job and as a hobby. I have a 200 amp pulse TIG welder from RTech. I have attempted to find specs on your WSE 200 unit but without much success. Does your machine have variable frequency? I feel that frequency of the AC welding current is the key to welding thin material as it really focusses the arc. The other point that is important is having a pulse setting. What this does is modulate your welding current using pulse width modulation.

What this amounts too is that it prevents thermal runaway and everything ending up as a melted mess. You set a maximum and minimum current and the machine switches rapidly between these two. So the pool forms but never gets out of control due to the cooling in the low current switching period. With pulse you can weld right next to an edge without melting it. I guess if the balance was more positive that would keep it cooler too but it is probably best staying with about 50/50. I think also a lanthanated tungsten is best for aluminium.

So, higher frequency if you can and pulse if you have or can afford to get a machine that has it. I am at sea at the moment but I am going to experiment with welding some thin aluminium sheet when I'm back in the UK in about 10 days. I will let you know my findings re frequency etc.

Carl.

Hi Rebekah,

For good results on thin metal a welder with pulse capability is very beneficial. As others have said, frequency and cleanliness are important. I find cleanliness of the stock and filler wire gives far better results than dirty metal on ferrous material too. If waveform control is available, triangular wave is great for thin aluminum stock also.

The best machine by far that I have used for TIG is a Miller Dynasty 350, but this is an industrial quality welder and they sell for around $8000 in the US. Luckily I have a friend with one. With one of these and some practice, virtually anyone can make top quality welds in just about any metal thick or thin. The cheap China welders, not the case. Any I've tried are fine on mild steel 1/8 to 1/4" thick but otherwise it can be very difficult to get decent results.

JD

Hello Becky,

I started out with a reasonably priced TIG unit that was by Sealey. Although they have links to the UK (Bury St Edmunds) They are in fact made in China…but hey, it had AC/DC functionality and for the price was a great little unit. Trouble was it was only just 150A and no variable frequency or pulse.

I soon realised I needed both these capabilities so I got a unit from RTech. These are a sort of halfway house – part Chinese but re-assembled and checked in the UK and with European power electronics. So still within a sensible budget but more functionality. Quite a good compromise, I thought.

I would echo Jeff's words on cleanliness and triangular waveform, but I reckon if you can get the pulse and frequency right you'll be good. I looked at your website on model truck construction and I have to say it is impressive. Whatever you are doing with your current TIG unit it seems to be working.

Do you have a BOC account for your argon? Another tip I'd like to pass on to you (and anyone else TIg-ing in the UK) is a company called Hobbyweld. They do gas bottles for the likes of us and they are considerably cheaper than BOC. There should be a stockist near you. You can find out here:- http://www.hobbyweld.co.uk

I am Merchant Navy…sort of. I work in the Offshore Oil and Gas industry. My job is to maintain, modify and fly Remotely Operated Vehicles. These are large underwater robots equipped with robotic arms. They can be fitted with a variety of tooling and are used to build subsea oilfields. A sort of underwater tractor.

You are right to assume a military connection though. I am ex Royal Air Force. I was an Aircraft Technician for 13 years until I left in 2002.

Best Wishes,

Carl.

Hello Becky,

Yes, I was looking at the WSE 200 and it does look like a great machine. It is a lot like my old Sealey unit was. I well remember Waddington, used to often get detached there as I was on Nimrods at Kinloss, we used to go and play with the R's at 51 squadron. Well I say I remember it, at least the bits of it I spent not in the pubs in Lincoln… I assumed you were an Electronics Technician, being Royal Signals.

I have a BOC account as well, but I'm seriously looking at going to Hobbyweld. Works the same as BOC but much cheaper. When the girl at my local stockist explained it to me I thought she was having me on!

Yes, always plenty of positions in ROV's for ex military technicians and especially for someone of the skill and calibre you display. If you are interested in finding out more please feel free to PM me and I can give you more details and give you some people to contact.

Best Wishes,

Carl.

Carl,

I'm interested in the hobby gas's.

At the moment I have full size bottles from Air Products, the ones that stand about 5' tall and about 9" in diameter, problem is I don't know what they hold as regards litres.

AP call these 230 and 300 [ litres ? ] One is argon MiG mix and one is pure argon for TiG

This months rental is £6.90 per bottle plus VAT making a total of £16.56.

MiG gas lasts me about 2 months and costs £28.00 odd for the refill.

Argon lasts a lot longer at probably 6 months and costs £48 per refill.

If you have access to hobby gas prices can you post them so i can compare.

Have a look at this John

**LINK**

Dosent seem all that cheap though!

peter

Hi Muzzer,

Thanks for that. The TIG brazing has seemed almost mythical until now and it is good to know that someone has actually done it.

John/Peter…thats not what the girl I spoke to at my local dealership told me, so maybe you are right and it isn't such a good idea after all.

what do you mean the tungsten is burning back

At low amps as you describe there should be no danger of this even a 1mm tungsten should be good for 60 amps plus a bit you shouldnt be above 35 amps asa start for what your joining a good rule of thumb is 1 amp per thousandths of an inch up to 1/4" thick and 1.5 amps per thou thereafter

we join steel in the 0.6mm to 6.35mm thick range daily and readily 0.9mm wall tube gets welded to 6.35 plate and thicker with no problems whatsoever but i spent years on a miller syncrowave welding thinwall bicycle frames together

1mm sheet is quite thick in my world do you have a footpedal? and understand frequency control for the AC higher means a tighter arc and less wander but it also means your mre likely to penetrate through

tungsten grind angle you might want to try greater than 30 degrees for less penetration

IME pulse welding aluminium is very hit and miss you are much better using freq and foot pedal you max amps will be set on the machine and that is what you have on tap at the pedal, no more

Using pulse means you have to take into account your on, off time and account for that if you are welding 30 amps peak for 0.2 seconds you dont have a chance of starting a bead you need to go up on your peak amp to near 90 amps

the one honest to god true thing i will tell you when it comes to welding thin material is you do get what you pay for with a more expensive welder that goes down to 3 amps ,sure many will say 3 amps is the lowest they will go but when you compare arc stability side by side of a high end machine to a an adequate far eatern machine you see the difference

I have not had ago at TIG welding, but I have a tame tigger (a profesional welder), he welds up parts for my hot air engines, displacers, and displacer cylinders. The thinnest has been .005" wall thickness SS tube, a .005" cap welded on, he did say don't bring too many of those, the other ones are about .007", and .012". Not sure what size rods he used, but the first thing he did was to grind a sharp point, then wind the amps down to minimum, I then went and gave his apprentice a hand. Nothing to do with aluminium, but I know that thin SS is possible. Ian S C