AC Tig First impressions & some q's

[ngt]

Well yesterday i tried my AC setting on an aluminium car radiator.
(Oxidised yes, tried to clean it but this thing is thin.)

Can anyone tell me if its really me, or is it AC double as bright in contrast with DC ??
I had set my helmet darkness to about 9 and everything was good and dark in the middle of the puddle @ a stainless pipe just minutes ago.
I switch to 40 Amps AC, i flick the switch and i got suprised, welding was about twice as bright and my ceriated 1.6mm tunsten spit its sharp end and balled like hell (ceriated is said it can keep its sharp point), and i got some light spots in my vision, set my helmet to about 11.
The 1mm alu sheet area didnt opened a hole even at 50-55Amps (no filler). Another spot of interest was the texture of the "welded" surface was like crap (see photo), the puddle as well as the arc while tig'ing, was very scattered and without definition, i've heard that AC alu is like that but that much ?
So -lack of puddle definition - bad texture of the weld -balled ceriated tungsten -and twice as bright are the things i want to have some opinons on! What do u think ?
Settings 80-100Hz AC, 70% balance, 50A, 6Lpm tried 7Lpm, 7 Cup, 1.6mm Ceriated.
One suspicion is due to the small thickness of the aluminium the puddle draws oxidised aluminium from the bottom but that much ? The end of each bead was shiny though...

 

[NTwoO]

Welding AC requires at least 11 on the mask.
That looks like rubbish drifting through from below or too little gas. Up the gas flow.
On what side of the 50% are you running on? ceriated tungsten should ball less than that.

 

[ngt]

Well the machine says just 30 to 70%. the manual is somewhere in the storage, but generaly speaking with ac balance the lower the setting the more reverse polarity and the more cleaning action. The higher the setting, the more electrode negative and the more penetration with a narrower band of cathodic etching marks. Tried 45% and 70% didnt really made much of a difference. I will try again today

 

[craigthewelder]

Our machine is the other way around.

Looking at the way your tungsten balled up i think your might be the same.

 

[hotrodder]

As said, sounds like your machine displays balance as %EP i.e to get 70%EN you'd set the AC balance to 30

Used castings aside an old, used radiator is about as hard as it gets weldability wise- the cores are of vacuum brazed construction and can be a right bitch to weld when new if not cleaned up properly. Add several years worth of crud and tickling it with a wire brush isn't going to cut it

 

[busa]

ngt.

You really need to dig out the manual for your set and establish whether your set displays balance as %EP or EN. The excessive balling of your tungsten is typical of too much EP.

As hotrodder says, you are really off to a bad start on material like the radiator you chose as a practice piece. You say that you 'tried' to clean it, thats not good enough where ali is concerned, it has to be spotless. If using a wire brush then it must be stainless, and must be a brush that you will use only for aluminium, using it on mild steel beforehand contaminates the aluminium and will cause problems.

The pics show that the arc has basically failed to break down the thick oxide layer and the wandering sparkly arc you describe is typical of this. Get hold of some clean ali and have another crack at it.

 

[NTwoO]

The soot round the edges also point to too little gas flow. Up it to 9 or 10 lpm for a 7 nozzle. I'll take a pic of my ceriated ally tip. Does not look like your tip.

Old corroded ally is a bitch, since a little porous ally will be rotten to the core. Fire up the arc and the trash starts creeping out of every pore. Some types even refuse to be welded. If you have an ally shop in the neighbourhood, go and dig in their scrap tin. They will usually not mind if you chuck your old practice pieces back in the tin.

 

[TheJoker]

This is good information. Following with keen interest! Thanks!

 

[ngt]

Ok I (at last) tried the opposite AC balance on my knob put it directly at 30%.
And i cleaned my surface at a sanding belt leaving some spots of oxidised aluminium on purpose.

It looks that aluminium is more sensitive to corrosion than steels.
My first pass was without any filler, look at how aluminium oxide acts like a paper sheet that burns away leaving a black outline. You can see this black outline created while welding, burning away like a cigarette paper.
Once to the clean aluminium the puddle starts to appear, at last, and you can get a nice bead ! Before that, the arc is all over the place trying to brake the oxide.

And after i was happy about the discoveries i laid a bead !NICE!
Pretty Neat for a 1mm aluminium sheet, i am again impressed with TIG welding!
Oh and one more observation is that when i was at the end of my filler try, just before the end while i was approaching the alu-oxide, the arc jumped out of the puddle and tried to flirt with the oxide ! Maby the alu-oxide has better conductance ? (doesnt show in the pic)

 

[busa]

Looks like you're making some good progress there ngt! much better now that you are on clean material.

 

[TheJoker]

That's good news! Nicely done in the video.

I do fail to understand the bananans in the garage though.

 

[NTwoO]

BTW, Where are you working? That looks like the dining table with a cotton cloth on it. This is not considered work safe environments with welding. Read the "set fire" thread for some ideas what can go wrong. The cotton will also not help anything if you get a drop of molten aluminium onto it. It'll burn right through and leave a neat reminder on the dining table never to do that again.

 

[ngt]

That's good news! Nicely done in the video.

I do fail to understand the bananans in the garage though.

Haha no Garage there mate, its the... KITCHEN ! Lol ! Tried to crop them at the video but they still show up !
I was waiting for a comment on the bananas, becuase they look cute.

This is not considered work safe environments with welding

Yup its the kitchen table ! Its a bit amateurish, i admit it. I have set fire on cotton cloths at my Garage with MMA so i know cotton is nasty !
But since TIG is on experimental stage and i dont have time to go to my garage-shop after my regular Job for my 15-20 minutes of experiment and 1-2 minutes of welding per week, so i came up with this home made solution.

Many say oh TIG is like other welding procedures with sparks and fumes and motlen blobs. This shows TIGs stuff. Welding and taking a fruit while sitting

Action at my proper garage

 

[powernut]

good info here , cool video if i ever get this good at alloy tig , ill be chufffed , ps i gather all tigs use differnert settings

 

[ngt]

Actually all my aluminium welds i've done all my life are the ones you see on the picture ! LOL, with a chineese welder and 6lpm gas flow
its not that difficult !
You need to clean aluminium veeeeery well, shave at least half a mm to make sure its clean !

Tig welding has a resemblance with drawing, my opinion.