Mig welding aluminium

[Downwindtracker2]

My first attempt at aluminium. I have a Miller 250x , a new Spoolmate 200 spoolgun, argon tank and 4043 wire. A low life stole the batteries off our travel trailer, so I've cut down a used lockable semi 1/8" checkerplate box. Not critical but lots of practice. Tips and tricks ? thx

[Russ Hanscom]

Been a while, but the material has to be extra clean, and aluminum gives no warning before melting & dropping. Best practice on some scrap first.

[redneckalbertan]

Aluminum oxide melts at a higher temperature than aluminum, so you want it really clean, I prefer a mechanical means, grinder. Clean it and weld it IMMEDIATLY. Don't give the aluminum a chance to start oxidizing. As mentioned by Russ it is a much difference critter than steel, giving almost no visual cues before the weld puddle looses all structural ridgity and falling out. You'll probably want to use straight argon as a shielding gas.

The only tip that I can think of right now is push the puddle with your gun, don't drag. Well the only tip other than the oldie, practice, practice, practice.

[warmstrong1955]

Pretty much what has been said already.....

Clean....real clean....clean clean clean. Not a good idea to use regular grinding wheels, as they leave behind pieces of themselves. Carbide burrs are best, and immediately before welding, clean well with a stainless steel wire brush.

And yes....push, don't pull, and keep the wire standoff short. I like a stop & start method. Comes out looking much like a TIG weld.
Be prepared to move faster as you weld too. No rheostat to control the heat, so as you weld along and the pieces warm up, you need to quicken the pace.

Bill

[ken572]

As mentioned by Russ it is a much different critter than steel, giving almost no visual cues before the weld puddle looses all structural ridgity and falling out.

In reference to above, after cleaning prep is done we used to take
and light the acetylene up just enough to get the black carbon flame and kind of
throw the carbon onto the prepped weld area and then when you start to weld,
as soon as the carbon dissapears you move and fill. It dissapears right before the
weld puddle looses all structural ridgity and falls out. I had a Very Very old timer
show me that trick when I was young. It also worked the same on the old pot metal
bumper components and mirror components that were cracked and needed repair.
This was a trick they used for welding aluminum and or pot metal with oxy/acetylene.
This old fella made his living restoring Packards, Cords, Auburn's and the like.
He also would take Stainless Steel angle iron and weld a small plate on each end, and
melt broken pieces of pot metal or aluminum into it and custom make his own welding
filler rod. It was a perfect parent metal match.

When the filler metal was cooled and solidified, he would pop it out with a screw driver
and clean it up with a file and wire brush and it was ready to use.

Note: The carbon goes away without contaminating the weld area.

Ken.

[redneckalbertan]

There are abrasive products for an angle grinder designed for aluminum that resist the loading of aluminum in the wheel that a standard steel wheel is very prone to. I can't remember the make of the one that I have used but it was very effective and did not load up. It was an interestingly designed disk meant for using on the face only and had bumps all over the surface which removed the metal. This isn't the disk that I've used but I have been happy with the other Walter products I've used: http://www.walter.com/en_CA/products/ab ... inding/alu

Flap disks are also very effective.

I have not used carbide die grinder burs with aluminum since joining this site but did not like using them because they can load up with aluminum if the bur gets a little dull and thus heats up. I have learned from this site that WD40 is used for machining operations on aluminum. I am assumeing that using this with a carbide bir would help with this problem but I don't know. Maybe someone else can comment on this who knows.

Ken, I have never heard the secret you mentioned about the acetylene torch before. I'd like to try that, it sounds like it could be the cats meow for a novice or one who does little welding of aluminum. I used to spend 4 to 8 hours once a year welding the stuff. Just enough time to remember what you are doing, only to forget in time for the next year!

[warmstrong1955]

I forget exactly what the discs we used were made of....calcium something or other.....might be what those Water discs are made of. Regular discs are bad news.

If you use the straight cut carbide burrs, and don't get too aggressive, they don't load up so easy. Can't say the same for the crosscut style. WD40 wroks really well at preventing loading on any of 'em, but like oil, is very unfriendly when you weld afterwards.

Bill

[ken572]

Ken, I have never heard the secret you mentioned about the acetylene torch before. I'd like to try that, it sounds like it could be the cats meow for a novice or one who does little welding of aluminum. I used to spend 4 to 8 hours once a year welding the stuff. Just enough time to remember what you are doing, only to forget in time for the next year!

The cool thing about it is it allows the welder a very small,
and some what predictable window of opportunity to deposit
your fill rod and move ahead before you loose it on the floor.
Make lots of practice coupons, to get good at it takes alot of repeated
practice, and refresher time through out the year.

Ken.

[Harold_V]

I forget exactly what the discs we used were made of....calcium something or other.....might be what those Water discs are made of. Regular discs are bad news.

"Regular" discs are aluminum oxide, well suited to grinding steel, but a poor fit for grinding aluminum. The abrasive of choice for aluminum is silicon carbide.

Harold

[Downwindtracker2]

Thanks for all the help. After getting a practice one that wasn't too bad, I tried the bottom of the box. Ugly would not describe it, in fact It was the worst looking weld I have ever done, and that includes a O/A on plate steel, my first attempt at joining steel some 40 years ago. I'm a retired millwright, but I've done time in sawmills.

The aluminum is .096 checkerplate,.035 4043 wire, I'm running it at 18.1 volts 411fpm. The machine is a Miller250x and a Miller Spoolmate 200. 100% argon

[steamin10]

As noted, aluminum is a different animal. It is only learned by practice. Two things that help: Argon is hotter than Helium. It glows a slightly different color. Puddle control is key, you have to see. ( I use straight Argon, expensive as it is.) Maintaining a pool of gas may include a simple cardboard box around your weld, to keep the pool together. Some pro welders use a cabinet, to the extreme of eliminating Oxygen to low levels.

Dropouts can be helped with a steel backer pressed close to the weld, as it acts as a chill. If it 'drops' because of speed influences, it is your learning curve, not to repeat the failures, speed, wire, motion. Aluminum is difficult when things are right.

With apology; I make statements that are superior in nature to the home guy. I have to express that I am NOT expert, and just an average guy that speaks to what I do. OK, so I do some aluminum with wire on my red machine that is set for 220 and gas. It is exclusive to aluminum, with higher power, as AL soaks up energy. It is better with Tig, where you dont add metal in pigeon poop, and can go back and melt foam into a bead, and then add material by rod and move on. More than one way to skin a cat. Some ways are easier than others. Real sensitive welds, I take to a friend that welds all the time on his truck trailer for damage as he works, and he does fairly well at covering my needs. So networking is very important.

As a side note, My buddy has cut aluminum fuel tanks in half, and made long range tanks, and tanks with two compartments, for fuel and a hydraulic section for the dump trailer. His truck is a simple machine of 1968 vintage, with a reworked power house 700 HP custom refit, built by him. His aluminum dump trailer is 20+ yrs young. I helped him strip it a few years ago to weld all the stress cracks in the frame and box. It is just projecting your craft. Buy or build, make money on your labors.

[warmstrong1955]

Interesting trick Ken!
I never heard of that either.

Bill