Ally lap joint

[PSweeney]

still practicing on ac, struggling with a 1mm ally sheet lap joint with the upper sheet balling up and melting away. I've found focusing the puddle on the lower sheet first and washing it up to it with a dab of rod helped but I felt like I was chasing it all along. Any advice on how to combat this ?

Second question, is the cleaning action proportional to amps ?

 

[Tom Orrow L]

Sounds like a job for Richard. I'm sure he'll be along soon

 

[Richard.]

The arc will always favour a side and it will always be the cut edge on the top. Once you've got a tack on the job it's loads easier as you then have something decent to start your run from. Getting the tack there is the bit that requires the tricks. Arc focus is key. Grind your tungsten to a point like a DC tungsten then spot a tiny flat on it (I mean tiny) to aid even balling. Turn your frequency up nice and high(120 - 150hz) is good and turn the balance to around 80% dcen. This is to get the tungsten to hold its point keeping your arc focused. Now it's tempting to gently apply current and try get a gradual pool but that's the worst thing you can do and causing the issue. 1mm you say? Hit it right on the joint at 50 amps get your fill straight in then get straight off the power. 1 tack weld in place. Now you've got your stepping stone to work off to finish the joint at a current you can keep control of. Good luck.

 

[PSweeney]

The arc will always favour a side and it will always be the cut edge on the top. Once you've got a tack on the job it's loads easier as you then have something decent to start your run from. Getting the tack there is the bit that requires the tricks. Arc focus is key. Grind your tungsten to a point like a DC tungsten then spot a tiny flat on it (I mean tiny) to aid even balling. Turn your frequency up nice and high(120 - 150hz) is good and turn the balance to around 80% dcen. This is to get the tungsten to hold its point keeping your arc focused. Now it's tempting to gently apply current and try get a gradual pool but that's the worst thing you can do and causing the issue. 1mm you say? Hit it right on the joint at 50 amps get your fill straight in then get straight off the power. 1 tack weld in place. Now you've got your stepping stone to work off to finish the joint at a current you can keep control of. Good luck.

Thanks very much Richard I shall try those pointers, I did wonder if it was technique or settings, so I'll give that a bach

 

[Richard.]

It's not easy to do simply because your mind is saying "are you bloody mad hitting that ally sheet at 50 amps" but it's the way to do it. Be quick mind get that fill straight in the pool and shut it off sharp. Fit up is crucial to its success so be sure it's nice and tight. Hope you get it after a couple of practice runs.

 

[Richard.]

Your location is a useful one should you wish to take part in a half days tuition at mine. Pm me if your interested.
5 members have taken me up on this so far and I think they were please with the results.

 

[cocker]

Get yourself over to see Richard ,
You'll save yourself a whole load of frustration - and time .
I did

 

[Brad93]

I was struggling with my aluminium tacking, I took a few goes to really nail the pedal you think I'm going to melt a big hole in the but when you properly commit to a massive but quick blast on the pedal, it just melts together nice.
I went up to see Richard and it was well worth the trip. He had me banging out lap joints after a few pointers and setting adjustments.

 

[Richard.]

I was struggling with my aluminium tacking, I took a few goes to really nail the pedal you think I'm going to melt a big hole in the but when you properly commit to a massive but quick blast on the pedal, it just melts together nice.
I went up to see Richard and it was well worth the trip. He had me banging out lap joints after a few pointers and setting adjustments.

You were a lot better than you gave yourself credit for. That fillet you did still sits under the bench looking a robot put it down.

 

[PSweeney]

Ok so thought I'd post an update. I tried the settings and techniques Richard which seemed to work great. The only issue is I'm struggling to keep a point on the tungsten, but with a tight arc and pulsing the pedal I was able to finish the piece I was doing with a balled end. I also needed far more amps than I thought but the material was actually 1.2mm thick. The set I'm using is borrowed and I don't like the foot pedal, full pedal is an uncomfortable position over center and it's quite notcher, so I whacked it to 90amps and just used part throttle / more amps as needed. Thanks again for the advice

 

[Richard.]

Pedal pulsing will generate a ball more than flat AC current. I think it's to do with a jolt of current then off then a jolt and it doesn't give the tungsten time to stabilise properly. 90 amps on 1.2 sounds very high. 60 would be where I'd be and I don't hang about so perhaps the readout isn't what it says. The balance needs to be well into the en part of the cycle if your to retain a ball and at 90 amps you should start thinking about a 2.4 which will hold its point better still.

 

[Rrunnach]

What spec tungsten are you using?

 

[Brad93]

The tungsten probably won't keep its point all the way down the piece, but it helps a lot at the start.
Just keep practicing washing that arc up onto the top sheet and you'll soon have the hang of it.

 

[PSweeney]

1.6mm gold tipped , lanthenated ?, had the set at 90a but was using prob two thirds pedal. Also found if I didn't keep up with feeding the rod it got away from me. Also highlighted the need to be able to feed the rod properly, whereas on DC I've got away with adding rod till my fingers were on fire, the amount of rod needed with ally has forced me to feed between my fingers.

 

[Richard.]

forced me to feed between my fingers.

Ally has a tendency to make us naturally learn this part of the skill. Without learning to feed through your fingers you become very limited to 3 inch runs at a time. Well done.

 

[Freddy0309]

1.6mm gold tipped , lanthenated ?, had the set at 90a but was using prob two thirds pedal. Also found if I didn't keep up with feeding the rod it got away from me. Also highlighted the need to be able to feed the rod properly, whereas on DC I've got away with adding rod till my fingers were on fire, the amount of rod needed with ally has forced me to feed between my fingers.

I know exactly where your coming from, I found sat there in the evening watching to etc I practiced feeding rod for an hour or two, (worth doing it with both hands as you never know) after a few evenings I was getting the hang of it and it's helped no end, I'm pretty sure it was jody from welding tips and tricks that recommended it but may be wrong

 

[Rrunnach]

1.6mm gold tipped , lanthenated ?, had the set at 90a but was using prob two thirds pedal. Also found if I didn't keep up with feeding the rod it got away from me. Also highlighted the need to be able to feed the rod properly, whereas on DC I've got away with adding rod till my fingers were on fire, the amount of rod needed with ally has forced me to feed between my fingers.

I have never used lanthanum grade tungsten, so I really cant comment, I assume they don't ball up like zirconium grade tungsten? It has probably been mentioned already, I use approx tilt angle of 70 x 70 degree for a lap joint, focusing tungsten onto bottom part of al/al sheet, but keeping close to top part of joint, too. Get the ends of the joint together a quick as possible, once this has been achieved, you should be able to complete joint fairly easily and, in a controlled fashion, apart from nearing end of run, then go like Billy Whizz

 

[paceman1]

as a question what amount of argon flow is needed when aluminium tig welding

 

[paceman1]

the gold tip type tungstens are they a universal tungsten

 

[Richard.]

as a question what amount of argon flow is needed when aluminium tig welding

Gas lens 5-6lpm
Collet bodie 6-8lpm
Gold tips are perfectly fine for ac and dc