Ac tig techniques

[oceanobsession]

What is the technique with aluminium. what is the black sooty stuff and can
you fuse it togeather like dc any help most welcome im new to ac cheers ocean

 

[matt1978]

Did you go for that Kempii machine of flee bay in the end mate?

You shouldn't be getting sooty welds on tig........is the Alu clean prior to welding, do you have proper gas flow?

It is possible to fuse this Alu together, but its no wear near as easy to do as with Steel or Stainless Steel.

Alu can be a bit of a toughie till you get the hand of it. Any chance of any pictures? Might be able to help a bit more.

 

[Paul.]

There shouldn't be any black sooty stuff, what gas are you using, its AC and pure argon for Ally, theres been some debate about DC ally tig on here, its possible on thicker sections, but only if your really desperate, and takes loads of cleaning of the parent metal and filler rods, the AC cycle has whats referred to as a scavenging effect, this lifts the refractory oxide from the surface of the metal, With DC this doesn't happen so cleaning has to be manual, Stick to AC save yourself loads of frustration, It'll look like this.

 

[oceanobsession]

Re ac tig techniques

Hi matt. ive bought a oerlikon citoarc tac 173 ac dc single and three phase
two hundred and fifty pounds seconhand. it welds great on mma crisp and on
dc it great aswell far better than my migatronic lte 200. you can get the littlest weld from it on thin stuff at low amps ive been having a go on alum
tonight so it might be me if you lay two strips down and run them in togeather it seems fine its when you put one ontop of another it seems like you have different temperatures and you have to wait for a while till the bigger piece gets upto temperature and you can get a bit of the black stuff
maybe its dirty ive got to get some rods yet ill post some pics tomorrow
cheers ocean

 

[oceanobsession]

Some pics

pictures

 

[Paul.]

Looks like poor gas coverage try it at about 8 - 10 lpm, how far out is the tungsten, for ally you need to keep it level with or just in side the ceramic, and use a fairly wide ceramic unless you need to get in a corner. Ive seen a lot worse than that though, you're on the right track.

 

[Shox Dr]

Clean, clean, clean, oh and clean again, it the 1st and last rule of welding Ali. The black soot is more than likely from a contaminated Tungsten, either from touching the work piece, or touching the filler rod to the tungsten. Either way as soon as it happens STOP and clean clean clean, regrind the tungsten and start again.

As for autogenous welding, you will find Aluminium will run together on a very tight fit-up but if you don't move fast enough it will key hole in front of the weld pool (what you should be looking for when adding filler rod) and then it will just get wider and wider (unless you add fill), you will also find the penetration is poor. If you need to do it then I would be stitching the reverse side with rod as well to give it some strength

 

[matt1978]

i cant see any Black soot on them mate.

They look clean.

The white area around the weld (run parallel to the weld) is the cleaning zone, I can see a couple of areas where you have touched down or touched the filler on the Tungsten, that sometimes gives a soot, is that what you mean?

 

[oceanobsession]

Re ac tig techniques

See this pic for soot but i think i may have stuck the tungstone down ocean

 

[Paul.]

The run on the edge looks a bit black, unless its my monitor, could be a touch down, thats why you need to keep the tip inside the cup,