Welding aluminum

[Mark @ Everlast]

I find that the biggest issue with MIG welding aluminum is that most people do not know how to recognize true spray arc. This is the best and only recommended way of welding Aluminum with MIG. But sadly so many people try to weld short circuit with aluminum wire and don't know the difference.

 

[hayden]

I find that the biggest issue with MIG welding aluminum is that most people do not know how to recognize true spray arc. This is the best and only recommended way of welding Aluminum with MIG. But sadly so many people try to weld short circuit with aluminum wire and don't know the difference.

When welding, how can I tell which I am getting/producing?

 

[Motorboatin]

When welding, how can I tell which I am getting/producing?

Type this into the YouTube search box......mig short circuit vs spray

Plenty of informative vids

 

[Mark @ Everlast]

When welding, how can I tell which I am getting/producing?

The wire never touches the puddle. Instead, it pinches off somewhere between the tip and the weld puddle, and forms droplets which then "shoot" into the weld puddle. This action is rapid and fast and consistent. It's a quite, steady hiss, instead of a "frying bacon" sound. Some people confuse this with having the voltage turned to high and the wire is burning back to the tip irregularly.
Depending on how your eyes are focused, you may be able to catch sight of the droplets as they form and enter the weld puddle.

Of course, the quiet hiss thing goes away if you are using a pulsed spray...then it sounds like you kicked over a hornet's nest.

 

[dragoneggs]

The wire never touches the puddle. Instead, it pinches off somewhere between the tip and the weld puddle, and forms droplets which then "shoot" into the weld puddle. This action is rapid and fast and consistent. It's a quite, steady hiss, instead of a "frying bacon" sound. Some people confuse this with having the voltage turned to high and the wire is burning back to the tip irregularly.
Depending on how your eyes are focused, you may be able to catch sight of the droplets as they form and enter the weld puddle.

Of course, the quiet hiss thing goes away if you are using a pulsed spray...then it sounds like you kicked over a hornet's nest.

Thanks for the explanation. Gonna have to see if I can force a spray arc and take notice.

 

[yomax4]

Thanks for the explanation. Gonna have to see if I can force a spray arc and take notice.

You will really need a higher argon content than 75/25 for true spray on steel. I use 90/10 or dial in a little higher on my mixer.

 

[Mark @ Everlast]

You will really need a higher argon content than 75/25 for true spray on steel. I use 90/10 or dial in a little higher on my mixer.

Technically, you are supposed to be able to do it with 80/20, but I personally use a C18 and it works great for spray, pulsed-spray, and short circuit. With short circuit though the higher argon causes less spatter, and gives a brighter weld (less cleanup), but can cold lap if you aren't up to snuff on your welding skills.

But yes, 90/10 is a great gas to use for spray or pulsed spray on steel.

On stainless, you can use 98/2 (98 Ar/2 CO2, or 98 Ar/2 O2 ) for spray, but trimix is best for short circuit, but it costs an arm and a leg. I've got a nearly fully 330 CF bottle of it. It hurt, and its been sitting mostly. Bet I haven't used 300 lbs out of it. Going to save on cylinder rent and turn it in. It hurts, but the cylinder rental is stupid.

But for Aluminum, the best and most common choice (and really the only one besides adding some He to it) is 100% Argon. No CO2...at all. And that is for short circuit and spray. Just the nature of it.

 

[dragoneggs]

You will really need a higher argon content than 75/25 for true spray on steel. I use 90/10 or dial in a little higher on my mixer.

oooh... good catch before I get frustrated. I keep forgetting the need to keep my eye out for a small bottle of Argon.

 

[BukitCase]

DragonMark and EverlastMark, here's a question I know just enough about to ASK; I've done exactly 3 MINUTES of spray arc - on steel, while demo-ing my VERY slightly used MM252 just before I bought it - seller had a nearly empty bottle of 90/10.

I do know that it takes higher voltage for spray transfer, but for what I do I can't see keeping yet another bottle around, since quite a bit of what I do is OOP and thinner stuff. I HAVE welded 3/4" stock with the MM252 using C25/.035 wire and multi-pass, and couldn't break it with a 20 ton press...

Anyway, I thought I remembered that the older transformer version of the MM211 (Marks, and my previous 211) only claim max open circuit voltage of 30 volts - whereas the newer Inverter MM211 (what were you thinking, Miller??!?) shows max open circuit of 54 volts. My total "spray" time with my newer inverter version MM211 is still at ZERO minutes (still no 90/10 bottle), but I'm wondering if the transformer 211 can even put out enough voltage to enter spray, or maybe only with a higher argon % ?

Enquiring minds wanna know... Steve

Edit - just checked the Miller mig calculator, for 3/16" aluminum spray they recommend .035/argon @ 425-450 IPM, 23-24 volts. D-Mark, looks like yer out of excuses :laughing:

 

[dragoneggs]

Thanks, Steve. You got me to get out of my office chair and into the shop to take a pic of the inside cover of my 211. See the bottom for the Al spool gun settings. Says for .030 wire and 100% Argon, the settings for 1/4in thick should be 10/90. That is max volts and 90% of max wire feed. So, theoretically it can be done. I am assuming this is spray arc.

My only complaint really with this machine is I don't ever know what the actual voltage is 'volts' and wire speed in 'in/min'??? :confused3::smiley_aafz:
If I read somewhere, or someone tells me a good starting point for a particular weld it means nothing to me. I would be lost without this chart and it also makes it difficult to use someone's else's welder because I am not learning typical settings.