Aluminium welding

[Aussie Mike]

Hi Guys,

After stuffing around with my MIG welder for some time now I've finally got it working well on Aluminium!! I'm happy as a Pig in poop since aluminium welding has been something I've been wanting to do for ages.

The welds aren't as nice as what you can do with a TIG but they are acceptable for what I want to do.

machine set up is a realy important factor in welding aluminium and it's a lot more sensitive to wire speed and voltage settings than steel. The other issue is getting the wire to feed properly and I think I've sorted this out as well as I haven't had a jam for ages.

One of the traps is that the teflon gun liner that most shops sell you for a Binzel gun isn't the whole kit. And if you install it just like a steel liner you're in for a bunch of trouble. What most of them sell is just the refill kit. You need a the wire sleeve that goes inside the gun and a brass tube for the wire guide back at the rollers.

The sleeve in the gun screws onto the end of the liner and feeds the wire up to the tip. If you install the liner without this on the last 8" or so of the liner the teflon liner melts on the back of the tip. The brass tube for the wire guide is important to keep the liner straight and butted up close to the feed rollers. The tip is also important in that you have to go one size larger than the wire you are using or buy tips sized for aluminium. Since the expansion rat of aluminium is greater than steel the wire can expand inside the tip and jam inside the close fitting hole. I'm using 0.9mm wire but running it through a 1.2mm tip.

To celibrate I knocked up my Quick Jacks. Chris Lidgerwood had some blanks water cut for me from 6mm aluminium plate. I linished them up and welded them together. I've just got to linish down the weld on the back and polish them and they are ready to bolt on.



Cheers

[cobbindale]

Mike,

Not bad for a beginner, only kidding.

Is there no end to your abilities. If I need so welding done I know were to come.

Cheers,
Dale.

[CobraV8]

Mike, how did you remove the aluminium oxide on the surface of the parts before welding?

I had no big success with MIG welding aluminium up to now because no matter how much I brushed or sanded the parts (to remove the Al oxide) the seams didn't penetrate the material well enough to really hold them together.



Simon

[PatBuckley]

You are using a stainless brush to clean the aluminum, right?

Mike -Neat! Can you post a list of the parts (with #'s if possible) that you need to do this? How much time do you have into this?

Pat

[Clois Harlan]

Mike,

I have tinkered around with welding alum with my mig welder with no success. I bought the whole kit plus a tank of argon gas (75%argon 25%oxygen). Welds don't hold and it looks like sh_ _ !

What is your wire speed and voltage settings?

Clois

[Dusty Rhodes]

clois, you need to use pure argon, not the mixture,

[CobraV8]

I did use pure argon but had the same problems as Clois described...

[Mando]

Top Job Mike.

Regards.

[Aussie Mike]

Sorry Pat but I haven't got the exact part numbers for the liner. I'll be pulling it apart and switching back to steel in the next day or so. I'll take some pictures so you've got a point of reference.

I'm using a Binzel torch on my MIG and they are pretty common here in Australia. I'm not sure if the parts are interchangable between torches. I figure each manufacturer will probably have a similar set up.

Binzel have a fairly comprehensive site here: Binzel

My torch is an older one they don't make any more but the consumables are interchangable with the new torches.

You definitely need straight Argon shield gas. You'll also ne U grove rollers for the aluminium wire. Normal V grove rollers for steel wire will cause you feed problems.

I'm no expert and I'm probably still doing things wrong but I'm starting to get some decent results. Some of the things I've found in my recent round of experementing:
*You need a lot more shield gas. I'm usually pretty stingy with my shielding gas for steel but I had to turn it right up to stop the porosity in the weld with Aluminium. I'm now erunning at about 25 litres/minute.

*You need heaps of current. MIG on aluminium only really seems to work well when you get to spray transfer current levels. This is when the current is high enough that the filler wire explodes of the tip in to fine particles of molten aluminium. This also blows the oxide off the aluminium as you weld. They reckin about 3/16" is about the thinest you can weld in spray transfer.

I've got a 200 Amp machine and I've got the voltage wound way up almost flat out and the wire speed is on about 6 out of 10. I found I wasn't using enough wire at first and had it around 5 and produced some ordinary looking welds.

Prep was done by linishing the parts prior to welding but not much else. I used a clean relatively new regular wire brush to scrub off the soot and oxide that formed on the weld. It comes off pretty easily. A stainless brush would be better.

The angle of your torch is far more critical as is the ength of your arc. I found that it's very unforgiving of lazy technique. If you close your arc up to close you will get aluminium adhering to the tip of your torch and it will jam. If you have your arc to long you loose control of the arc and it jumps all over the place.

Hope this helps.

Cheers

[427sharpe]

If you have a Lincoln welder (mig), their aluminum kit comes complete, you install it and go. I had really good luck with mine. And yes, you do have to abrade the surface with a NEW, aluminum only cleaning stainless steel brush (don't use the brush for anything else).
Anyhow you look at it, those welds look GOOD!
Clois...practice practice practice (and when you give up take a welding class at your local JC..best $ I ever spent!).

[Tenrocca]

Mike,

Mig question for you. Ive only done a bit of welding with my mig I got a few years ago with mixed results (practive makes perfect). Last bottle of gas I went through lasted about 3 minutes so obviously I had a leak somewhere. Any tips on how to detect a leak? Also at 35 buck a pop those disposable bottles aint cheap. Any better alternatives?

Cheers

[Aussie Mike]

Hi Tenrocca,

Certainly sounds like you have a leak. I'm not familiar with the disposable bottles. Are you running a regulator?

The best way to find leaks is a squeezy bottle of soapy water. Squirt it arround the joints and your along your hoses and bubbles will appear when you find a leak.

I have 2x E size bottles for my welding kit. They are about 1.2 metres tall and about 25CM in diameter. One is straight Argon for the TIG welder and for the MIG when I do Aluminium. The other is Migshield which is a mix of Argon and CO2.

Unfortunately you can't own your own bottles in Australia any more and you have to rent them from the gas supplier. The prices have been jumping up a bit in the last few years. When I first got the MIG about 14 years back it cost me about $230 for a 5 year lease on one bottle. These days they only let you do a yearly lease and it costs about $115 a year per bottle.

A refill of Argon is about $80 from memory and the migshield M1 is less. I go through about a bottle a year at my current work rate but I'm pretty stingy with the gas. I usually run the Migshield at about 7litres/minute inside and a bit higher if there's any wind or strong draf. th TIG needs les gas at about 3 or 4 litres/minute but you are welding for longer so I guess it evens out. I recently bought a gas lense for the TIG which makes a more concentrated gas shield andI think it uses a bit less gas.

So it's an expensive option to rent bottles and maybe disposables at $35 a pop is not a bad way to go if you don't use the machine a lot.

Cheers