Welding aluminum with a MIG

[ahtune69]

Hi Matt,



I have a miller 185 mig,is it possible to weld alum?
If not what da ya suggest without purchasing a tig.

Thanks

Mike

[Kenova]

Hi Matt,

I have a miller 185 mig,is it possible to weld alum?
If not what da ya suggest without purchasing a tig.

Matt, I'd be interested in hearing what you have to say also.
Ken

[Matt@RFR]

Well, keep in mind that I've never personally tried what you're talking about, but have read up on the subject, and have heard first-person accounts too.

From what I understand, you can look forward to much frustration. Aluminum wire is so soft, that it's really difficult to push long distances. At the slightest hint of a snag, it'll birdnest in an instant. (Birdnesting is when the wire tries to stop in the liner or gun somewhere, and balls up right before the drive roll(s).) The trick there is to set drive roll tension just tight enough to push the wire up to, and through the gun. However, if something snags, you still have a feed problem, but without the birdnesting problems. Therein lies another problem...when the drive roll(s) slip on the wire, it tends to create a flat spot on the wire, so when you do get the original problem cleared, once that flat spot hits the contact tip, you will probably have another snag.

Assuming you don't have an aftermarket gun on your welder, you're actually at an advantage with the stock gun because they have short leads, and shallow angle necks. My 400 amp Tweco, 15' lead, 45º neck gun wouldn't fair as well. You will also need to put a teflon liner in your lead, and only use that liner for aluminum. Keep your lead as straight as possible to minimize bends in the wire's path.

To add to the possibility of birdnests or other feed problems, aluminum MIG in conventional power sources likes to "pop" when you start the arc, and burn the wire back to the tip, which makes it stick.

Some guys have had success with this setup, but to be honest, I don't know them personally, and I can't comment on their experience as weldors, or if their results were truly exceptable.

Also, Mike, I believe your original question was aimed at welding thin aluminum brackets. Aluminum MIG is not a process that was ever intended for sheet thinner than 1/8", and that's pushing it for butt and outside corner welds!! Trust me when I say that you have to be quick and steady to have any success. 3/16" and thicker, you bet!

That actually brings up another problem. Aluminum MIG is really best ran in spray mode, and it takes a lot of amperage to get up in the spray amperage range. When run short arc, it's inconsistent, and spatters like crazy. I'm not sure the 180 class MIG's have enough amperage available to spray aluminum wire or not.

Along those lines, if you blow a hole in your weldment, you might as well toss it if MIG is all you have. Filling holes in aluminum with a MIG, particularly in thinner sections, is truly a b*tch.

To reliably MIG weld aluminum, you'll want to look into a spool gun or a push-pull setup. . The spool gun would need a seperate (I believe) contractor box, but the push-pull guns are direct bolt-in's as far as I know....They are in the 250 and up machines. Ofcourse, for the ultimate in MIG aluminum, this bad boy is what you want. Put a 30 foot push-pull gun on the 350P (P=pulser), and it'll weld .040" aluminum sheet WITH A GAP, UP HILL with no spatter!!!! I have considerable experience with this setup, and love it. Plus, change wire and gun, and you have a very nice steel/stainless machine. But at $3900 with no guns, it's probably for pro's that do a LOT of aluminum MIG welding. The only thing I don't like about the 350P is that the pulse parameters aren't adjustable, but it works well.

By all means, try it out if you want and let us know how it works out for ya. In any case, a few pointers for aluminum MIG:

-Straight Argon or Argon/Helium mix's only.
-Push or zero travel angle. If you pull it, it will have black soot beside the weld, and may even show some porosity.
-'bout 25cfh of gas
-Lots of stick-out. 3/4" is good. You can run the nozzle way out so it looks like your normal stick-out for steel.
-Clean clean clean! Clean aluminum will also help keep the "pop" at arc start to a minimum.
-Spray transfer, not short circuit.
-Dwell in the puddle, or even go backwards over solidified weld to prevent a crater forming at the end of a weld. If you have a crater, it creates a stress riser, and if the weld fails, it'll start to fail at the crater (assuming a good weld, otherwise).
-Lots of tacks!

[ahtune69]

Thanks for the info Matt,don't sound like i'll be doing any alum with my mig.
I'll ask around and see if I can borrow a tig.


Thanks
Mike

[Einstein1]

http://www.readywelder.com/home.htm


Used to weld aluminum. Check it out you can buy them on ebay.

Matt

[SatisTraction]

yes you can. i have a miller 185 with an aluminum set up. you need to buy the spoolmate 185 spool gun.