TIG - Unstable arc

[David Beckett]

Hi,

I am pretty new to TIG welding and my welder came with no instructions so I'm having to learn the hard way but I am gettin there.
When I got the machine I put a thread up on here (https://www.mig-welding.co.uk/forum...der-with-no-instructions.104014/#post-1755166) and they helped alot, I managed to lay some semi decent looking ally welds down on a bit of tube.

But I went away did some DC welding which was fine, ran out of gas, has to buy more and here I am a few months later trying to weld ally again. But It won't work.....

the issue I am having to me, seems like there is a MASSIVE flame front almost coming out the side of the arch area. I messed around for ages and the best result I can get to even make a pool is turn the amps right down, however if I got by the 40amp per mm rule, i dont even get a puddle.

All I get is a big flame front, a big black dirty hole, and its melts a section of the ally about the size of a 1p. My issue is the flame front thing, I can't even get the filler rod near it, it just melts and turns very dirty. This all confuses me because I managed to get a good result before, but now its just a diaster and very frustrating.
The gas bottle says it is 100% argon.... but I am wondering. But being such a newie I want to explore every avenue before I got back and blame someone.

BEFORE

AFTER

and this rubbish picture is what I mean by flame front, I can't even get close to the tungsten and the flame looks green to me

Any help appriciated

Dave

 

[Mr Roo]

Dodgy/cracked tungsten maybe?

they are brittle rather than ductile, so there’s every chance you’ve dropped it at some point and it’s got a new point halfway down it where it’s also arcing from.

 

[David Beckett]

Dodgy/cracked tungsten maybe?

they are brittle rather than ductile, so there’s every chance you’ve dropped it at some point and it’s got a new point halfway down it where it’s also arcing from.

I have a pack of brand new tungsten's, white tip so i took 3 out of the pack, sharpened them and tried all 3. No change. I also fitted a new cup, but made not difference so went back to the old cup but not changed.
I took the gun apart, all looks ok. Collet was very slightly wavey but nothing major and the other part which the lense screws to looks ok too. I really am stumped.

I am getting to the point I may have to take the welder to a shop so someone who knows what they are doing can have a go, I don't know enough really to be able to place my finger on it!

Thanks for the reply

 

[David Beckett]

One thing i noticed earlier was the flame front seems to partially 'latch' onto the rod as I try and go near it, it's bizarre!

 

[Tangledfeet]

This may sound obvious but are you just taking the photos on a wooden surface, or are you trying to TIG weld on the wooden surface..?

Otherwise gas flow issue? I had similar results when the solenoid valve on an old welding machine failed and didn't open when I initiated the arc with HF start.

 

[Tigman]

How much gas litres per min ?

 

[Robert Weaver]

have you tried switching back to DC and running on some mild steel ?

if it's ok on steel, this points to the machine's AC switching electronics.
if it's not OK on both aluminium and steel, could be the gas (regulator fitting, air leak) or gas or torch arrangement (is the ceramic cup plated inside with metal?)

 

[stuvy]

Gas issue it looks like to me

 

[David Beckett]

This may sound obvious but are you just taking the photos on a wooden surface, or are you trying to TIG weld on the wooden surface..?

Otherwise gas flow issue? I had similar results when the solenoid valve on an old welding machine failed and didn't open when I initiated the arc with HF start.

Hi mate,
thanks for the reply.

This two railway sleepers , but just out of shot is a piece of 8mm stainless steel plate that i use to tig on top of, its usefull for soaking the heat out of the alu part. To make sure I wasn't get some silly reaction with the stainless i did try quickly just welding on the wood, made no different apart from lots of lovely smelling burning wood haha.

I can hear plenty of gas coming out the torch and the postflow working aswell. I do wonder if its dirty gas

 

[David Beckett]

How much gas litres per min ?

I don't have a flow meter yet, I was trying to get the basics before i really invested, but i have one of the 12L bottles with the rotational wheel on the side marked 6 to 15 with a lever to turn on and off. Ive tried it with the bottle maxed out, that made the situation worse! i'm guessing cause its only a number 5 cup

 

[David Beckett]

have you tried switching back to DC and running on some mild steel ?

if it's ok on steel, this points to the machine's AC switching electronics.
if it's not OK on both aluminium and steel, could be the gas (regulator fitting, air leak) or gas or torch arrangement (is the ceramic cup plated inside with metal?)

I havent' actually, I might do that tomorrow and report back.
ceramic cup is not plate on the inside, just a normal pink cup. I swapped that to and from with a brand new cup the same as i read something about the cup can become a conductor if its cheap or something, but no change.

 

[David Beckett]

I spent Hour trolling through this forum the other night and google, and then I came across this....

, It look bloody simular to that with the crazy noise, but more bottle 100000% says pure argon for tig with all metals

 

[Tigman]

Certainly looks like that could be it ?

 

[Munkul]

If it's the gas (or even if it's a bad leak inside the machine/hoses dragging air into the Argon) then you'll notice it on steel too... and the tungsten will suffer, it will oxidise instead of staying silver.

 

[David Beckett]

WELL IT IS SORTED!!!!

I cannot believe it, I was watching a video of a guy taking a torch apart and putting it back together and i saw him messing around with the collet and the issues you can have, then it occured to me.... I wonder!
I went home after my night shift and well I never, THE COLLET WAS IN THE WRONG WAY ROUND! Tbh I can't believe it fits in my torch both ways round, worked perfectly fine in terms of holding the tungsten, but must of been partially covering the holes in the torch or something. MADNESS

7am, laid down some very rubbish looking ally TIG welds, but it did what it should so i'm a happy boy.

Definatley one to remember, thanks for your help everyone, much appreciated

Dave