Aluminium weld pool

[Rob77]

Hi just started tig welding again after 15 years out of it,trying to do aluminium t fillet joint but can’t seem to get the molten weld pool to join from the to plates any suggestions many thabks

 

[Hood]

Hi just started tig welding again after 15 years out of it,trying to do aluminium t fillet joint but can’t seem to get the molten weld pool to join from the to plates any suggestions many thabks

A dab of the filler when the pool forms on both sides should join them.

 

[Rob77]

Ok brilliant is it quite normal sometimes for them not to join

 

[Hood]

Yes, Aluminium can be a pain at times often it doesn't want to join the two molten pools unless you add filler. It makes it quite difficult to tack up thin stuff whilst holding the parts with one hand and the torch in the other. If I have to do that I sometimes fist put a blob on one part then when I place the part to be joined the extra material of the blob often allows it to fuse to the second part.

 

[brockenhammer]

Hi,
pulsing the current should help with that in some cases because of the swinging of the pool.

 

[Richard.]

I agree. Pulse on AC is a waste of time. Never found any advantages from trying it.

 

[brockenhammer]

For the usual welding I don´t use pulse on AC mode either. Even when tacking I do it like Hood mentioned. Building a blob on both sides, and letting it flow together then.


But there might be an advantage when tack welding with pulse. I´m not shure if only on dc mode, but why not on ac?

There is a fronius video about it.
Just search on youtube: Fronius tig welding tacking function


Of course these effects often work and can be prooved under very constant lab conditions, but in practical life you would choose another solution.

 

[brockenhammer]

Usually I do steel, here are two pics of really bad fitup on a geometry prototype (nothing I would do on usual frames, of course). Tacking is pain here also, because the gap is nearly 5 times the filler diameter.
The chainstay is 0,8mm the big part is 6mm. Pulse helps a little with the control here and let it flow together.
Maybe what they called "Badschwingungen" (pool swinging) in literature helpes with ally too. But that might be just in theory.