Alu Fillet weld help

[Misterg]

beginners such as myself

And myself - I found I had to get the tip of the tungsten *much* further into the corner than I was comfortable with to get decent fusion on fillet welds - Jody's video above shows it very well towards the end. The trouble with a lot of these things is that the differences are subtle. If you know about them, they stand out like sore thumbs; if you don't, they're very difficult to spot. It's worth watching the 'how not to' bit of that video a few times and pausing to take in what he's saying. It sounds like chat, but it's actually very concentrated information.

 

[Cheesie]

More amps is needed as has been said above, I prefer to get a puddle quick and get moving,
advice on what amps can be difficult with aluminium as a lot can depend on the size of the work piece i much prefer a foot remote and set the amps much higher than needed,

 

[minimutly]

Pros will say you don't need a pedal, but I found it difficult to gauge how many amps needed.
the pedal allowed me to wang it up early on, get a root puddle, then back off slightly as moving allong.

 

[Cheesie]

are they pros? it depends on what your welding, for instance when welding all 4 sides of box section you need less amps on the last weld, coming to the end of a run on most things you will need to back off, in my day job there are no foot pedals as it takes up too much time moving them around, but then there's been no real need because the work I do is low grade stuff

 

[minimutly]

I think the point made was use the 2t 4t options. I did explore using a long slope down, to good effect.
My feeble brain and infrequent use made 4t impossible...

 

[Munkul]

are they pros? it depends on what your welding, for instance when welding all 4 sides of box section you need less amps on the last weld, coming to the end of a run on most things you will need to back off, in my day job there are no foot pedals as it takes up too much time moving them around, but then there's been no real need because the work I do is low grade stuff

Americans can't seem to TIG weld without pedals, on anything!
I wouldn't bother with a foot pedal unless it was thin or small stuff that has to be perfect. But I'm not a pro either lol

 

[mtt.tr]

Americans can't seem to TIG weld without pedals, on anything!
I wouldn't bother with a foot pedal unless it was thin or small stuff that has to be perfect. But I'm not a pro either lol

All Americans?

 

[Munkul]

All Americans?

Most of em, going by YouTube and the forums I visit...

 

[Brad93]

5lpm is the problem you need a least 6-8lpm, have a read of this thread especially post 7

Aluminium tig guide getting started.

As has been requested by a small number of members I'm happy to start a small guide as a starting point for newcomers into welding aluminium. The idea is to simply give you a starting point so your new toy can be taken from the box and dialed in without the grief of guess work or diving through...

www.mig-welding.co.uk

Not with a #5 cup.

 

[Brad93]

If you're welding aluminium in any way to a professional level a pedal makes your life much easier.

 

[Ubique]

Right, I've been trying to analyse the issues:
Tried a No.4 cup - no significant difference, back to a No. 5, Argon still at ~5l/m. I've watched the video above a few times, I can't understand how the tip keeps it's point rather than balling.
I was using 3.2mm filler rod on the 5mm box section fillets, possibly too big and cooling the weld pool too much, as a consequence I was probably moving too slow to get the heat back in.
I've gone back to 3mm practice pieces to get this sorted, the 'side to side' helps a lot with getting a puddle on both pieces, I do find that the overlapping piece (i.e. the one with a visible edge) is very easy to get too much heat into and it either deforms or blows through.
On that note, I think another problem with the 5mm box was some of the cuts were not great, I thought the fillet would fill the gap, I think what was happening instead was the air behind the joint was contaminating the weld - there was no easy way to get shielding gas in behind the fillet.
A cleaning run also seemed to help, the picture below is three separate fillets (even though it looks like hit & miss!) after a cleaning run, the start wasn't great and I added barely any filler, just a dab at the start to join the two puddles.

And another, again, not a great start and (i'm guessing) too hot at the finish, hence the blow-through. In some ways it's frustrating, I have to keep reminding myself I've only got around ten hours 'flying time' on Alu TIG - and that's what practice pieces are for eh?

The black line on the top piece is -I think - contamination, the one halfway along at the bottom, I'm not sure what caused that. That one didn't have a cleaning pass.

Thanks everyone for your ideas and guidance, I'm going to hold-off on the 5mm stuff until I get more competent with 3mm.

 

[Migmad]

A quick supplementary question if I may...
Corners - Am I right in thinking it's best to start a few mm from one - and either stop before one or continue round? Will starting or stopping on a corner cause a crack as it does laying fillets on a flat plate? again, apologies for the bone questions!

No you will be fine going to the end just remember to ease up off your foot pedal and make sure you push plenty of wire it to finish off to prevent pin holes