Mig welding aluminium

Welding Techniques, Theory, Machines and Questions.

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rustyh
Posts: 326
Joined: Tue May 01, 2012 1:21 pm
Location: Hornby Island, B.C., Canada

Re: Mig welding aluminium

Post by rustyh »

Wasn't getting anywhere this morning with my vee welds (material meeting at 90 degrees) and had to grind off welds and disassemble stand I'm making for all the angle grinders. They act like coat hangers, just seem to breed uncontrollably.... :roll:

I then pulled out a 4043 roll in desperation (was using 5356). Oh my....what a difference. All the vee welds went quite well (meaning I feel chuffed, but any half competent welder would howl laughing), and hardly any smut. Now I know why none of the suppliers in town, but one (and he only had one roll), had any 4043...they were all sold out! The gun came with 5356, just assumed that would be okay.

I've got the Argon at 25cfh, as the Miller's owners manual says between 20 and 30cfh. I'll lower it for inside shop work.

One immediate welding noise was immediately apparent. With 5356 I would get zzzzzzzcrackplopzzzzzcrackplopzzzzzcrackplop.....with 4043 zzzatatatatatatatatatata....

5356 supplied with gun hard to see puddle, blob would form run up on wire then drop to puddle, 4043 easy to see puddle and wire spraying to puddle (no climbing up the wire) just above puddle. Night and day....wonder if the 5356 is a bad roll?

Off to the shop to play some more. Other than the frustration, it's been a lot of fun.
Carm
Posts: 457
Joined: Fri Jan 18, 2008 5:14 am

Re: Mig welding aluminium

Post by Carm »

From your description of sounds of the arc, you are on the verge of globular/spray transfer. You want spray.
4043 has a lower melting point than 5356 and won't weld with the same parameters. Whatever wire you are using, try making slight tweaks with the feed on the gun to get the steady sound. That's more convenient than going to the machine and adjusting voltage but of course they are related. My experience with guns, a small movement on the feed has massive results, but that was years gone by and probably new stuff is better...
Stick-out is more critical with aluminum MIG than steel. Small variation can get out of the spray transfer pretty quick.
Read up on filler/parent metal recommendations. One size doesn't fit all. 4043 with some alloys will give lots of cracks.
rustyh
Posts: 326
Joined: Tue May 01, 2012 1:21 pm
Location: Hornby Island, B.C., Canada

Re: Mig welding aluminium

Post by rustyh »

Thanks Carm,

My gun has only an adjustment for feed pressure (Spoolmate 100) all else gets done on my Miller 211. I did find reducing the voltage gave somewhat better results. Still have blobbing at the start until the alu heats up, usually between 1/4"-1/2" then it settles in and I speed up. Definitely works best at the recommended height and if I raise or lower the tip it becomes instantly noticeable.

Have my grinder frame more or less done so I'll start practicing with 4043 and 5356. I had to get all the grinders onto a movable rack to make room at the bench so I have a place to practice inside, at the bench, out of the wind and rain.

When all is right I am amazed at how nice the welds look, this from a guy who has only used flux core. Won a little money on the lotto yesterday that will allow me to set up another tank for welding steel, Argon/CO2...man this gets expensive..... :roll:
BuyMetal
Posts: 2
Joined: Mon Jun 29, 2015 10:29 am

Re: Mig welding aluminium

Post by BuyMetal »

Aluminum is great because it can be easily formed and machined, and readily accepts a wide variety of surface finishes. Check out buymetal.com and see if the selection there can help you.
dirtcrasher1
Posts: 112
Joined: Sat Oct 15, 2011 6:45 pm

Re: Mig welding aluminium

Post by dirtcrasher1 »

I find speed and voltage set up correctly is a constant bzzzzzzzzzzzz.

That's what works beautiful for steel which is chicken compared to aluminum.

Aluminum is tough, clean clean clean and the right voltage and wire speed control have to be dead on......

And something someone said to me the other day, "that aluminum from the scrap yard, is it labelled??" I said no, that's the truth. He told me to get some 6011 and it's labelled every 10"s or so. Some aluminum will not weld. Most of my Al. are embarrassing at best to share with you guys.

I am 2 years into a brand new 180 Miller, I cannot offer this service to my customer because it is not a layed out bunch of dimes.

I NEVER thought Al. would be this difficult, it's why I bought the machine. I'll keep it but I'm getting a spool gun for my Mig for Al. I have the smallest of repairs ton do for myself and I can't do them and it kills my enthusiasm to even try. But, I continue on.

Other than that, 1 S.S. brush labelled "TIG ONLY". And a grinder that says Carbide on the right wheel and Al. on the left. It's all I can do until I can do aluminum very well. So far, it's like butter in a microwave...
EOsteam
Posts: 240
Joined: Thu Jan 31, 2013 1:33 am
Location: Pendleton, Oregon

Re: Mig welding aluminium

Post by EOsteam »

Here is some fairly concise but usable information about aluminum grades that comes from the Aircraft Spruce and Specialty Co.

http://www.aircraftspruce.com/catalog/m ... uminfo.php

2024 and 7075 are not considered very weldable.

HJ
User avatar
BadDog
Posts: 5131
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Re: Mig welding aluminium

Post by BadDog »

If you are going to try to do small welds in aluminum where cosmetics are at a premium (row of dimes), then I would say to forget MIG/GMAW, even with a gun. You can get good solid welds with practice, but not generally premium cosmetics. For that really nice look and non-production volume, TIG/GTAW is the choice. Still tough to learn, but lots more options and easier to get nice cosmetics.
Russ
Master Floor Sweeper
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