Aluminium Welding - Possible with cheap MIG?

[malcolm]

My first attempts at aluminium welding didn't go too well. I'd manage a quick spark and then the wire would crumple up at the wire feed. Seems aluminium wire is a lot softer than steel wire.

I should be able to fix a few problems. My wire liner looks like it has a steel inner rather than the lower resistance teflon inner. I haven't bought myself a oversized tip yet, I could perhaps try to find some more suitable rollers - the steel ones damage the wire. Also I could try 1mm wire instead of 0.8mm.

Can anyone think of anything else I should be doing (other than buying a welder with a motorised torch!). Also, anyone know of a supplier for Clarke welder bits - the current torch and cord were from Machine Mart, so I'm guesing they won't sell them with teflon wire feeds.

 

[Hitch]

My first attempts at aluminium welding didn't go too well. I'd manage a quick spark and then the wire would crumple up at the wire feed. Seems aluminium wire is a lot softer than steel wire.

I should be able to fix a few problems. My wire liner looks like it has a steel inner rather than the lower resistance teflon inner. I haven't bought myself a oversized tip yet, I could perhaps try to find some more suitable rollers - the steel ones damage the wire. Also I could try 1mm wire instead of 0.8mm.

Can anyone think of anything else I should be doing (other than buying a welder with a motorised torch!). Also, anyone know of a supplier for Clarke welder bits - the current torch and cord were from Machine Mart, so I'm guesing they won't sell them with teflon wire feeds.

Hi Malc...
I have done some Aluminium welding with mig, but not a great deal.
Even with a top of the range industrial machine and teflon liners it can still be a bit tepremental!
However it is possible!
Firstly, keep you torch as straight as possible (i always say it, but it makes a big difference!) and get yourself a Teflon liner, (if you have a euro coupled torch, just replace the liner, im not sure about the other types having never used them! Release the tension on your feed mechanism to. And as you mention a 1mm tip, or a 0.8 lightly filed out with a nozzle cleaner.

The spares for your welder like tips and things are universal, try here
http://www.diywelding.co.uk/products.asp?d=12&c=34

 

[malcolm]

I have done some Aluminium welding with mig.......... it is possible!

Thanks, that makes a difference. With my failures today I'll imagine that most folk who buy alu wire and argon gas from Halfords don't get all that far with it before giving up.

The torch and cord should be universal. A euro conection would be wonderful, but mine isn't like that. Mind you, any cord I buy is going to have a power line, a wire feed and a gas feed. And I already have the appropriate connectors so if the worst comes to the worst I can shorten and botch.

I'll buy a SIP cord with a teflon wire liner and a bigger tip and report back on progress later in the week.

 

[Hitch]

If you can justify it, that website also does a kit that will convert your machine to a euro connector.

 

[malcolm]

I've made some progress today! The old torch I've had sitting on a shelf has a plastic wire feed. I fitted that to the welder, positioned the liner as close as possible to the feed rollers, and drilled out the tip from 1mm to 1.2mm. The wire feed works fine now. Here are some pics of my best weld yet:

From the front:

And from the back:

I've found aluminium welding to be an all or nothing thing. Either the penetration is poor or I blow holes. The Lincoln Electric page on Aluminium welding suggests welding quickly, and that seems to do the job.

The settings are odd. I'm welding 2mm aluminium, and I'm using the same power setting as I'd use for 1mm steel (minimum). But I've found the wire speed needs to be close to the setting I'd expect for 3mm steel.

I'm concerned that the 2 pieces of aluminium don't seem to be mixing very well. There is a definite line on the reverse of the weld where the joint was even though I've got a lot of penetration. For lower penetration welds the penetration seems to occur either side of the joint with no metal in the joint itself. Any ideas what could be causing this?

 

[Hitch]

Im no expert om MIG ally, but would say you have your set slightly low.
The trouble with aluminium, it always looks like it is about to drop away! Wether it is or not.
Try turning up the setting, and moving slightly slower, this will still get the required heat for the penetration, but allow the two side to fuse together a bit better.

Trial and error i think matey! :roll:

 

[malcolm]

I found the problem. I hadn't cleaned up the edge of the aluminium before welding and the oxide stopped the two sheets from mixing. Here is the reverse of a weld where the edges were cleaned with a rasp file just seconds before welding. The light coloured line in the photo is the filler wire, but the crack has gone and the weld seems strong enough.

Trial and error it is. I've started to get the hang of sheet welding with a low power setting and a high wire speed. It's much easier welding bigger sheets as the heat has somewhere to go.

Tried an outside edge using the same technique and it was a complete mess. My technique so far for an outside edge is high power, a lower wire speed, and rocket like welding speed. Here is a pic of the outside edge (ignore the hole)

Unfortunately my first real welding job is going to be an outside edge weld repair on an aluminium wing, and the aluminium I hope to weld to is thin in a couple of places:

I'm going to have to practice a lot more. I think this will justify a BOC argon bottle as the tiny 60l bottles only seem to last for a metre of weld.

 

[Hitch]

Good luck Malc!!

Have you tried doing the joints with a backer behind the weld? This will prevent the weld from dropping away, ideally copper of brass, but a decent piece of ally will do the trick. (as long as you dont get excesive penetration.)

 

[malcolm]

Thanks for the excellent advice - a block of brass behind the weld works a treat. Here's a corner weld:

With the brass taking all the heat out I can weld with enough power to generate a nice arc, and weld slowly enough to achieve a neatish weld.

The back of the weld looks lovely. Here's the back of a flat panel:

Better still, I worked up the courage this afternoon to do that repair to the Aston wing. It's not my neatest weld ever, but it's nice and strong:

I'll write up what I've learned here for the website.

 

[kernowcam]

The rate your going malcolm you will be able to start on my landrover panels soon!!

 

[kernowcam]

I have a more immediate problem though. We have a pair of brake calipers (kawasaki) and the lugs, the outer pad presses against have corroded so the pad sits at and angle to the disc. The corrosion is a bit pitty. The advice so far is to build up with weld or put on a 'wrap' of say stainless and fill with jb weld behind or it is 'monkey' metal with a lot of magnesium (the pits) and will not build up / weld.

Any thoughts advice?
(nice photo sequence malcolm)

 

[Hitch]

That sounds like a tig job, using a rod with a higher magnesium content.

 

[kernowcam]

do you know of anyone in cornwall / devon who is good at such a thing.
I found a guy nearby who is highly reccommended but giving up!!! He said he would not do it / work due to the magnesium content. I am sure he's spot on but bless him is not keen to take on any more work. Unfortunatly the calipers are stupid money and are not bad enough to warrant replacement.

 

[Hitch]

Alderman Tooling in Plympton might be worth a ring.
Cant think of anyone round here, but im sure the must be some!
Somerset/Dorset i can tell you of half a dozen

 

[cammy9r]

hi, Ian you could try a web search for techno weld. This is a rod which needs no flux and has a similar application as brazing. I'm sure the site said it was suitable to use on Mg.
I was going to get some to repair my engine cases but chickend out and used some JB weld instead.

 

[Superbad]

This is the kind of subject I need to brush up on,as I am hoping to to do some ally welding,a 3mm thick flange to 3mm tube. I rang up Sip and unfortunately,they didn't make tips larger than 0.8mm.
here's an interesting setup on the gas bottle http://www.mig-welding.co.uk/aluminium-setup.htm

 

[faero]

I am planning to do something identical to this wastegate bracket (welded onto the housing on the left). The tab and the housing are Aluminium.
Had orginally planned to make up a steel structure from another area - not welded to that housing) but this is simpler.

Have a Clarke 135 MIG and a bottle of Argon.

Am I kidding myself? Wrecking the housing (thick) is not an option!

 

[shenion]

I would not attempt that with a 130A MIG, would use a 180A minimum.

If you have a decent torch you can try alum brazing.