help out a lost cause (Alumium TIG)

[Jim Davey]

What does your collet look like? I've had issues where people screw the back cap down so hard they buckle the collet blocking the gas ports on the collet body.
Bottle should say welding Ar, not welding Ar Mix, just make sure you've got the right stuff.

 

[Seventynine]

yeah bottle says "welding AR" on it, i checked and rechecked haha.

i pressurised the whole system to 30psi with no drop in pressure anywhere, sealed all the joints with PTFE,
i cranked it up to 15lpm and you could feel the gas coming out of the holes all around the collet

will try with stainless later on this week and see what happens, thanks guys!

 

[norlander]

yeah bottle says "welding AR" on it, i checked and rechecked haha.

i pressurised the whole system to 30psi with no drop in pressure anywhere, sealed all the joints with PTFE,
i cranked it up to 15lpm and you could feel the gas coming out of the holes all around the collet

will try with stainless later on this week and see what happens, thanks guys!

I just found that the rubber O ring on my torch back cap was torn-I appreciate you have pressure tested your system now so that is not relevant to your problem but thought I'd post it for info of any others who might read this thread.
Hope you get it sorted.

 

[Seventynine]

still not ruling out a gas fault, as the symptoms do likely lead to that

when screwing in the back cap, is it meant to sit all the way in? i noticed there was a good 5mm between how it sits with the collet removed and how it sits with the collet in place?

 

[Jim Davey]

The gap isn't usually that big, but it does depend on the torch and who made it. Provided the o ring isn't visible it should be sealing properly. It's a shame you're not closer as it looks like the kind of silly fault I'd get to the bottom of in five minutes if the set was I front of me.

 

[norlander]

Brake cleaner is surrounded by myths, it's NOT the toxic ticket to death that some make it out to be after reading about the idiot that poisened himself. Yes, he was using brake cleaner but the important bit is that it was chlorinated brake cleaner and IIRC he admitted to stricking an arc on a part that was still wet with a highly flammable solvent ANY chlorinated solvent can decompose producing phosgene when heated which is maybe one of the reasons why the stuff is pretty much outlawed in Europe these days and why brake cleaner in the UK is the non-chlorinated variety. Americans need to be vigilant as both flavours of brake cleaner exist over there

If I remember correctly, the the argon shielding gas contributed some kind of reaction to the gas given off?? its academic to me as I am not about to start inhaling solvents- heated up or not- we breathe enough crap in going about our daily business as it is as far as I am concerned.

 

[norlander]

probably going to make a prat of meself here but here goes- I sometimes find the collet needs a gentle nip up as its expanded and got a bit slack and if you don't watch it you compensate by ramping up the back cap to tighten down on the tungsten.

Angle of dangle? I've found that by getting the angle of the torch wrong for some joints/jobs you shoot the gas along the job and it sucks in air behind it (kinda like when you stand near a waterfall and feel the breeze) and messes up the job.

Never welded ally though.

That completes my knobhead input of SWAG.

 

[Brad93]

If I remember correctly, the the argon shielding gas contributed some kind of reaction to the gas given off?? its academic to me as I am not about to start inhaling solvents- heated up or not- we breathe enough crap in going about our daily business as it is as far as I am concerned.

Argon is inert, it doesn't react easily with many other elements or compounds. That's a room temperature albeit, perhaps in an arc it might.

You mentioned you use ceriated tungstens. Personally I have a RTech 201, I use zirconated and get on okay with them.

Quick question that hasn't been asked yet, are you using the pedal or the torch? The only time my AC welding was coming out that bad was when my pedal had broken. Switched to the torch on 2T And had no more issues, just try that first and see if you can run a better bead. R-tech will replace a broken pedal or can tell you how to fix it, which is what I did. Also switch your balance around to about 10-11 o'clock.
No pulse, AC frequency around 100 hertz should do that. I start with my tungstens ground to a needle point and let it ball off slowly, I don't ball it on purpose like some.

 

[SBK]

You mentioned about your back cap, is your tungsten firmly gripped when fully tightened?
I recently bought a wp9 torch that didn't always grab it properly and turned out to be a rough bit of thread on the lense side.
A quick run through with a tap and all sorted.
Just a thought .

 

[hotrodder]

If I remember correctly, the the argon shielding gas contributed some kind of reaction to the gas given off?? its academic to me as I am not about to start inhaling solvents- heated up or not- we breathe enough crap in going about our daily business as it is as far as I am concerned.

Argon is a noble gas, as said pretty much unreactive and thought to be totally unreactive until fairly recently... http://www.newscientist.com/article...forcing-noble-gases-to-work.html#.U0MUdKIfWE8
AIUI it's UV radiation and/or heat reacting with chlorinated compounds and decomposing the vapours that forms phosgene

still not ruling out a gas fault, as the symptoms do likely lead to that

when screwing in the back cap, is it meant to sit all the way in? i noticed there was a good 5mm between how it sits with the collet removed and how it sits with the collet in place?

Jim's pretty much covered the back cap thing but FWIW... http://www.mig-welding.co.uk/forum/threads/my-first-goes-at-tig-welding.38690/page-2#post-428470 It will always screw in further without a collet in the torch as it bears against the collet to force that to grip the tungsten.
Obviously i don't know how you pressure tested things but a leak in the torch due to the backcap or whatever won't show up unless you block the ceramic and then activate the gas solenoid*. What happens you're welding with a dodgy backcap etc is the argon flowing through the system draws air into the gas stream. Exactly how a venturi works

* if you use your thumb you're likely to get a tickle from the HF

 

[doubleboost]

This is very similar to a exhaust gas test on a MOT
If the system has a leak it will draw in air and give a high Lambda reading
(nothing to do with this post but interesting non the less)
Just shows how much a small leak can cause problems

 

[Seventynine]

Argon is inert, it doesn't react easily with many other elements or compounds. That's a room temperature albeit, perhaps in an arc it might.

You mentioned you use ceriated tungstens. Personally I have a RTech 201, I use zirconated and get on okay with them.

Quick question that hasn't been asked yet, are you using the pedal or the torch? The only time my AC welding was coming out that bad was when my pedal had broken. Switched to the torch on 2T And had no more issues, just try that first and see if you can run a better bead. R-tech will replace a broken pedal or can tell you how to fix it, which is what I did. Also switch your balance around to about 10-11 o'clock.
No pulse, AC frequency around 100 hertz should do that. I start with my tungstens ground to a needle point and let it ball off slowly, I don't ball it on purpose like some.

Spoke to R-Tech today over something completely seperate and asked them about my TIG, they said that the pedal i've got is the older design (i've had it for 6 years now) and that it's likely that'll be the cause, and if it is they'll replace it under warranty

will try it in trigger mode later!

 

[Seventynine]

Right so i took the welder 150 miles to a friends house, used his materials, his gas and BOOM. instant perfect welds

switched up the tungsten to a 2.4, aside from that everything was similar.

got back to mine and it was the same as before, i was nearly going to put it all up for sale i was so frustrated.

picked up a scrap bit of 1.5mm pipe and guess what....? PERFECT BEADED WELDS (well not perfect, but you could actually call it welding)

measured the thickness of the last lot of offcuts i bought - 1mm. either it's the thickness or there's a coating or it's monkey metal. either way i'm happy that i'm good with 1.5mm+

anything thinner will come after a bit more practise i'm sure

 

[Seventynine]

*actually call it welding* looks like this -

 

[Tigman]

Would it be that the sheet is anodized ?

 

[Wendelspanswick]

If your aluminium sheets are door kick plates they are anodized.

 

[Tigman]

Has anyone tryed to weld anodised Ally ? what happens ?

 

[Wallace]

The anodising is a non conductive oxide coating on the surface, try sanding the surface back then welding. Looks like you are relying on the sheet being good and clean to get a good weld, the surface in the photos looks like a production finish ie brushed, etched and anodised. Try cleaning the surface back with emery cloth by hand you will feel the difference once through the anodising as the cloth will skim easeily over the anodising and the ally will grab. Think of it as a coat of paint.

 

[rkde]

Just out of interest when you went and tried it else where did you have the foot peddle? I had a similar issue and it was a dead peddle, went to the switch and all was OK

 

[baconbarm]

For what its worth, I was in a similar position a few months back.

After a ten year lay off from tig welding, I was asked to do some alu work.

Cut a long story short, I hired a set for the week. Once I was actually welding, the welds were fine but the first few seconds were unpredictable at best, flaring up etc.

It turned out to be a faulty regulator, what was happening was the gas would blast out like a hairdryer for a split second, then return to normal.

I would have sussed it out sooner, but I had earplugs in