Thread: Tig Welding Aluminium Problem

Hi,

I've Tig welded on & off over 17 years but never had a problem until today. In that I was using a 3 phase CIG 180 AC/DC Transtig for the first time. those who are familair with the machine know that it has 3 lines of various current. There is an handle you pull out to move a slider to approximately the amps you require and lock it in position. Anyway having done some runs on a scrap piece (from the material I used to make the item) which were OK. However, when I came to weld the item I couldn't get it to weld - it would just blow holes. I suppose all good welders should be able to weld using any machine but I have only ever used machines that had either a pulse torch or a foot pedal that allowed the operator to vary the amps as you welded (which this one doesn't).

Btw, I did scatch (with a brand new wire brush) the to be welded area and cleaned it with acetone. I also cleaned the filler wire. I have attached an image of the type of welder I am referring to.

As anyone else had difficulty with this type of CIG welder?.

Cheers
David

Hi Metalhead

Given that the machine had the correct tungsten -

Zirconiated -white tip -or lanthanated grey tip

that the tungsten diam and amps set suited the aluminium thickness

was set on AC HF. Is there a start/constant control for HF

Some machines particularly if they have been used in air arc gouging are wrecked for finer arc control as insulation between the transformer shim stacks is R**ted.Arc settings tend to jump up as heat moves uncontrolled the transformer core .

failing that you might pick something up here
http://www.ckworldwide.com/technical_specs.pdf

it a PDF download so you will need Adobe Acrobat installed

Grahame

Originally Posted by Metal Head

Hi,

I've Tig welded on & off over 17 years but never had a problem until today. In that I was using a 3 phase CIG 180 AC/DC Transtig for the first time. those who are familair with the machine know that it has 3 lines of various current. There is an handle you pull out to move a slider to approximately the amps you require and lock it in position. Anyway having done some runs on a scrap piece (from the material I used to make the item) which were OK. However, when I came to weld the item I couldn't get it to weld - it would just blow holes. I suppose all good welders should be able to weld using any machine but I have only ever used machines that had either a pulse torch or a foot pedal that allowed the operator to vary the amps as you welded (which this one doesn't).

Btw, I did scatch (with a brand new wire brush) the to be welded area and cleaned it with acetone. I also cleaned the filler wire. I have attached an image of the type of welder I am referring to.

As anyone else had difficulty with this type of CIG welder?.

Cheers
David

David, have used the same machine a long while back, but all I can tell you is that the shunt adjust was a pain. When the amps were adjusted, it would move physically, but would jam internally which would lead to a kick to the side of the machine. Still doesn't explain your problem though- new wire brush, maybe some small particles embedded in the material,perhaps the acetone wasn't that pure and left a residue- I used to use electrical contact cleaner as it was pure and left no residue.

Obviously you are using a weldable grade AL. otherwise you couldn't weld the job either.
Like Grahame said, could be an internal problem.

Just for interests sake, do the leads on the welder give you a bit of a buzz whilst HF is operating? almost every Transtig I have used gave me a tingle through the leads.

Regards

Hey metal head Im not the best but I can try and help. I weld more of the exotic metals like titanium ect, what exactly do you mean by blowing holes, is it instantly dissapearing in front of you or is the material collapsing on itself and leaving a hole afterwards. Next are you getting a stable arc to start with or is the arc wandering. Is it oxidising, what gas are you using are you using straight argon or a mix, are you scratch starting or hf, need the additional info. PS I have the new model transtig and yep they have a tendency to zap you every now and then
Steve

Thank you very much Grahame & Anthony for your excellent replies. I did use the appropriate electrode unless someone painted over the original colour. It was set at AC/HF, although I didn't understand your question Grahame Is there a start/constant control for HF?.

Anthony I know where you are cominf from in regards the shunt adjustment being a pain and a half. I'm glad I didn't have to learn on this machine or I would have given up on aluminium welding years ago but I was fortunate to have learnt on ESAB/Miller/Migatronic welding machines. The material was weldable because I tried on a couple of pieces prior to rolling the material which was OK. However you may have hit it on the head to offensive particles being impregnated in the local area maybe although I had scratched it thoroughly with a wire brush it was unable to get them all out. I ended up riviting it up it didn't need to be welded.

Cheers
David

hi Metalhead

some machines like the Millers can have a cut out on the HF which starts the electrode via HF ,then drops out while you weld. It is there to avoid nasty restrikes outside the welded zone.
if your are doing a P/ vessel job or a test these strikes outside the "weld Zone can result in a FAIL.

The insulation gouging problem I mentioned causes an arc blow problem.Heaps of good welders are ruined by gouging for periods over the machine duty cycle.
If you have stick leads hook them up and see if there is arc blow.Or get and electrician to do an insulation test on the tranny. If its not giving trouble on other metals my moneys on contamination of the metal.

The bloody things can give trouble around the HF unit points gaps and cause all manner of weird effects, not often but often enough to make life interesting.

Another rush of poop to my brain suggested that a cause could be the environment the aluminum was in before it came to you.
I'm wary of the crap people have people put on a piece they present to the welder to repair.When araladite ,super glue,tarzans grip and silicone all fail people take it to the welder an expect success.

Aluminum is very porous and has the capacity to suck in all sorts of contaminants. If a piece looks at all like someones been there before me ,I am reluctant to weld it.



I am glad you have fixed the piece.
Grahame

Originally Posted by simso

Hey metal head Im not the best but I can try and help. I weld more of the exotic metals like titanium ect, what exactly do you mean by blowing holes, is it instantly dissapearing in front of you or is the material collapsing on itself and leaving a hole afterwards. Next are you getting a stable arc to start with or is the arc wandering. Is it oxidising, what gas are you using are you using straight argon or a mix, are you scratch starting or hf, need the additional info. PS I have the new model transtig and yep they have a tendency to zap you every now and then
Steve

Hi Steve,

Sorry for the oversight but I must have been making up my last post when yours was uploaded. So you weld titanium not the easiest of materials to weld if my memory serves me correctly. whilst in the airforce I got the opportunity to weld up some heat shields off harrier & tornados jet fighters. Am I correct in saying that you cannot afford for the filler wire to move outside the gas envelope as contamination will automatically take place on re-entering with the same filler wire. It is also like chewing gum in that the filler wire can stick to the outer weld pool if not warm enough?.

I have completed the job now by riviting the joint. I decided not to take the risk of undoing the good fabrication work. It is a scratch operated with this model - which I don't like. It is also used on a positive ode with AC & HF.

Thanks for your help.

Cheers
David

Originally Posted by Grahame Collins

hi Metalhead

some machines like the Millers can have a cut out on the HF which starts the electrode via HF ,then drops out while you weld. It is there to avoid nasty restrikes outside the welded zone.
if your are doing a P/ vessel job or a test these strikes outside the "weld Zone can result in a FAIL.

The insulation gouging problem I mentioned causes an arc blow problem.Heaps of good welders are ruined by gouging for periods over the machine duty cycle.
If you have stick leads hook them up and see if there is arc blow.Or get and electrician to do an insulation test on the tranny. If its not giving trouble on other metals my moneys on contamination of the metal.

The bloody things can give trouble around the HF unit points gaps and cause all manner of weird effects, not often but often enough to make life interesting.

Another rush of poop to my brain suggested that a cause could be the environment the aluminum was in before it came to you. I'm wary of the crap people have people put on a piece they present to the welder to repair.When araladite ,super glue,tarzans grip and silicone all fail people take it to the welder an expect success.

Aluminum is very porous and has the capacity to suck in all sorts of contaminants. If a piece looks at all like someones been there before me ,I am reluctant to weld it.

I am glad you have fixed the piece.
Grahame

Thanks very much Grahame for your concise answer(s) - much appreciated. I can see those pupils of your are fortunate to have such a knowledgable person/tradesman teaching them the trade. I will for one bare in mind your theories in that should I have a problem whilst trying to weld aluminium again.

Thanks once again David

Hey what a small world, I used to be in the RAAF as well, not as a welder but as a mechanic, used to work with the welders up in tindal for refurbishment of the afterburners ect on the hornets, learnt a lot from the guys there especially one old time carlos sacero or something like that, which made me decide to get myself some tickets, titaniums not that bad just got to envelope the whole job in gas, I reckon alluminium can be a harder thing to weld, solely because we have a tendensy to cut corners, not clean properly, not prep the filler wire ect, but with titanium you go threw the steps religously. Okay got to go now enjoy
Steve