Ally welding help

[Lee Patterson]

Looking for some help please guys. I have been stainless welding for a few years and have no problems with that. I recently got a cheap ac welder to have a go at ally welding and am having some problems. I can run a puddle on a piece of ally but I came to try and weld two bits of plate about 1.6mm today and couldn't get started. It is as if the melting parts of metal on each piece repell each other so they don't melt together like when doing steel? I also cannot get the wire to drop in the puddle and run as this too appears to be repelled away? I flipped over one of the test pieces and ran over the inside of a corner joint and could get the puddle to run fine if not a bit flat. But as soon as I have two separate bits to join no go? What on earth am I doing wrong. I have tried varying current up and down. Adjusting the cleaning balance. No joy.
I amean using around 45 amps but have been 30-65 without success.
1.6 zirconiated tips. 1.6 filler rod, 7 litre/min flow on pure Argon. Just using a straight Ac current setup with no pulse or anything. And a no.8 ceramic cup.
Really appreciate some pointers as I have watched videos and read some stuff but cannot see where I am going wrong.
Thank you
Lee

 

[carbon]

I think you need more current possibly nearer 80 amps

 

[Wendelspanswick]

Looking for some help please guys. I have been stainless welding for a few years and have no problems with that. I recently got a cheap ac welder to have a go at ally welding and am having some problems. I can run a puddle on a piece of ally but I came to try and weld two bits of plate about 1.6mm today and couldn't get started. It is as if the melting parts of metal on each piece repell each other so they don't melt together like when doing steel? I also cannot get the wire to drop in the puddle and run as this too appears to be repelled away? I flipped over one of the test pieces and ran over the inside of a corner joint and could get the puddle to run fine if not a bit flat. But as soon as I have two separate bits to join no go? What on earth am I doing wrong. I have tried varying current up and down. Adjusting the cleaning balance. No joy.
I amean using around 45 amps but have been 30-65 without success.
1.6 zirconiated tips. 1.6 filler rod, 7 litre/min flow on pure Argon. Just using a straight Ac current setup with no pulse or anything. And a no.8 ceramic cup.
Really appreciate some pointers as I have watched videos and read some stuff but cannot see where I am going wrong.
Thank you
Lee

You need a really good fit up, no gaps. I tend to tack on 1.6mm by blipping with about 100 amps and no filler if I can help it. Once I have my tacks in place I start my run on a tack, using the pedal with it set on a max of 100 amps but working on about 70 amps upwards.

 

[zx9]

Is it old aluminium? Have you cleaned off the oxide layer with a stainless steel wire brush? Got any pictures?

 

[Richard.]

Your task is a tricky one but a few little steps will make it happen. Fit up needs to be tight. It's also going to help if you get that puddle going quickly so as suggested above remove the oxide layer well at least where you intend to tack. 45amps isn't enough. Your heating it too slowly then when you get your puddle it goes straight through. Try a short sharp blast of 80-90 amps you may need a dab of filler you may not if the fit up is tight. Then as wendelspanswick says start on the tack and produce the run. I'd do it a little lower perhaps around 60.

 

[Richard.]

Oh almost forgot. Keep the arc focused well with a high frequency. Point on the tungsten and keep the balance biased into the negative polarity 70% so that the point remains focused.

 

[langy]

Your task is a tricky one but a few little steps will make it happen. Fit up needs to be tight. It's also going to help if you get that puddle going quickly so as suggested above remove the oxide layer well at least where you intend to tack. 45amps isn't enough. Your heating it too slowly then when you get your puddle it goes straight through. Try a short sharp blast of 80-90 amps you may need a dab of filler you may not if the fit up is tight. Then as wendelspanswick says start on the tack and produce the run. I'd do it a little lower perhaps around 60.

Thats exactly what I have been doing today

 

[Lee Patterson]

Thanks for the reply guys. If I go much over 70 amps I am sure the tungsten disappears? I have the balance at 50% usually so I can shift that around nearer to 70% as suggested and give that a crack. Should I have a 2.4 tungsten really? Is white tip the best? Should I be sharpening it to start even if the end is going to ball up?
Will have another crack. Fit up on my work piece is good. Test bit is just two pieces lapped over one another. All cleaned before starting. Maybe not enough?
Thanks again
Lee

 

[Richard.]

No don't step up in size. 1.6 is perfect for the current your using. A lanth would ball up less than a zirc (blue or gold) 50% balance is the reason for your tungsten balling up at higher current go to 70% DCEN this will resolve that and 100-120 Hz.

 

[Richard.]

Yes sharpen it.

 

[langy]

I generally find ally tricky to get going but a dab of rod in the initial puddle will get you going

 

[Lee Patterson]

Thanks for the reply again Richard. I am going to give it a whirl now! When you refer to 120hz due you mean pulse setting? I am on a straight Ac tig setting at present. Thought I would go one step at a time as I have never used pulse and that involves playing with even more knobs!

 

[Lee Patterson]

I have to say I wasn't expecting it to be so much more tricky than stainless!

 

[langy]

Thanks for the reply again Richard. I am going to give it a whirl now! When you refer to 120hz due you mean pulse setting? I am on a straight Ac tig setting at present. Thought I would go one step at a time as I have never used pulse and that involves playing with even more knobs!

Don't use pulse its not neccesary, I don't think you have frequency control on your machine

 

[Richard.]

No not pulse 120hz AC frequency if your machine permits.

 

[Lee Patterson]

Don't think I have that setting option. Anyway, the advice worked a treat. Still need to get the hang of ally generally but I adjusted my balance and found where the tip stayed nice I was then able to wind the current up and tack together the pieces. I even managed a bit of a weld. A bit high on current I think as it started to melt through near the end of the run. But progress!
Thank you so much. I actually tacked my work piece together too. But need more practice before I run a weld on that. It's seems you rely on the rod a lot more than you do with steel welding? And you need to be quite quick feeding it in?

 

[langy]

Don't think I have that setting option. Anyway, the advice worked a treat. Still need to get the hang of ally generally but I adjusted my balance and found where the tip stayed nice I was then able to wind the current up and tack together the pieces. I even managed a bit of a weld. A bit high on current I think as it started to melt through near the end of the run. But progress!
Thank you so much. I actually tacked my work piece together too. But need more practice before I run a weld on that. It's seems you rely on the rod a lot more than you do with steel welding? And you need to be quite quick feeding it in?

I'm assuming you have a pedal ? Get going and get a puddle going then you can back off slightly as the heat gets into the job, yes you need to feed the rod a lot quicker

 

[Richard.]

Ally has many properties that make it very different to welding ferrous materials. The oxide layer melts at 3 x higher temp than the actual aluminium so generating the puddle requires high current but then when that puddle is going the high current becomes too much this is where variable current control is essential. The other thing is aluminium has a thermal conductivity about 4 times greater than steel so welding it when it's hot requires a lot less current than from cold. It behaves and welds in such a different manner. Put up some progress pics of your work.

 

[Lee Patterson]

I am running off a trigger control. However I can see the benefits a pedal would have. I have the option of 4t and 2t. As I recall one of those allows you to use a higher start current and then drop off to a lower weld current? Maybe that is all to do with the pulse settings?
Will send up some pics when I make some progress! I am away for a few days so today was my last chance to get in the garage for a bit.

 

[Lee Patterson]

Here are a couple of images from my efforts this evening. I am getting on reasonably we using the 4t function on the trigger. I am wondering about getting a cheapo £60 foot pedal to try and see how I get on?
One other question I have regards my ally welding. How do you know where a good place to set the balance is? What denotes more or less cleaning required?