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Aluminium MIG welding


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Having decided a while ago i was going to cut the roof of the RR and then alu-MIG it back together, I had already acquired the bits requried for the mig, today i picked up some pure Argon whilst i was at the gas yard getting some more Ar/Co2.

All-green is pure Ar, blue with green is Migweld Universal - Ar/Co2/o2 mix.


New 4m teflon liner.


1.0mm tip, oversize for the 0.8mm wire


Small reel of alu wire, next to the 0.8mm mild steel reel i took off.


Changing the liner over is no hassle really with a Euro torch, it's easy to get the liner out.

Here you can see the Euro plug, with gas, wire/current and trigger (x2) connections.


Unscrew the cap, and pull the mild steel liner out.


Then slide the new teflon liner in. I trimmed the end off once the liner was in.


The torch-end of the liner is trimmed too, I left it a little long, so the tip butts up against it.


The tip screws up fine, but i'm wondering if the liner is blocking the gas holes slightly, gas flow (pressure) is set high on the reg at the moment.


The wire was fed through the rollers and into the torch, Alu wire is incredibly soft. the tip of the wire was sanded smooth and the euro torch was stretched out straight.


Roller tension is set at an absolute minimum (normal is 2 -3), the alu wire will birds-nest easily so to have it slip is better than to waste 4m of wire.


First impression on trying some welding was "wow, this is completely different!". wire feed has to be a lot higher and as exected the power setting needs changing once the metal is hot, hence the foot pedal on a tig. This end of the test piece show the first few goes i had, bottom right shows too much juice. the mess along the middle was one of the first goes, the alu weld pool seems a lot less stable than with mild steel, the wire will quite happily move around, or just burn right back to the tip. Welding leaves everything covered in a black/blue/white soot, that easily comes off with the stainless steel brush.


This end of the test piece shows some improvment, trying a continuous run is pointless, the heat has a dramatic effect and you end up with too much pentration, then a hole. All of this was done with the stop-start technique. The porous welds are due to not enough gas, I found the reg had to be set much higher than on steel, this may be due to the new liner restricting gas flow a bit, or maybe alu needs more gas?


With varying degrees of penetration.


I tried welding some extruded alu (built-in cupboard door runners :rolleyes: ) with not-so-great results, I'm not really sure why, it was difficult to get the arc and weld pool stable in the corner.



Happily, results were better on thin sheet, especially as it's RR roof i really want to weld. The following pictures show sections of RR roof off cuts, cut in half and then welded together again.

This photo shows the front of a weld.


With too much pentration, blow-through can't have been far off.


A different view


This piece was done with less power, and with the alu against steel sheet. the top looks better. I've ground down some sections to show what penetration is like, and what the finish can be like.



The back has less pentration than before, which has come up against the steel sheet, again i've ground it down to show a 'finish'.


To finish, welding aluminium seems to produce a helluva lot of smoke and splatter (I had been warned of this), The visor shows the smoke from this afternoon.


More practice required, hopefully i'll get some more time in a couple days.

Comments? questions? p!ss takes?

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i have done some ali welding using a butters mig. it was difiicult to do, especially as i was using one of the very small argon bottles u can get from machine mart.

it took a lot of practice but i found the only achieveable way of doing it was small spot welds. it wasnt like tig but it did the job, like u have done already, its lots of practice.

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Yeah My results went along the same lines. I used standard tips and standard liner. Plenty of tip dip helped but the bigger tip and teflon liner are the biz. It`s weird isn`t it?...like lighting one of those Magnesium tapers. I took the lil roll of ally wire and wound it onto a 15kg blank. I notice you have same welder as me........ by Tecnical Arc Services. Found you needed a lot of power wire speed and gas at 15.


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how are you getting on with the 5kg roll in a 15kg holder? I'll pm you an alternative

try without getting a weave on - just beam it in and keep hustling along, it WILL get easier :)

gaswise you need to run higher CFM than ferous, be aware that too much flow also risks porisity from turbulence.

wear a high necked jumper or you'll get a tan - reflected arc from Alli is much better at giving you that lovely winter glow than mild :)

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how are you getting on with the 5kg roll in a 15kg holder?

Bodged it! stripped the 15kg holder down to the spindle, the threaded section of which is just long and thin enough to hold the diddy reel. I'll grab a picture tonight. It's going down fast, wire feed is through the roof compared to mild.

Trying to weld the thicker stuff together, the pool really wouldn't let me move it along with a weave, as you can see. I'll take your advice and try again without a weave.

Long sleeved rugby shirt, collar up, seems to do the job.

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I have tried this in the past, had minimal luck all I can offer advice wise is :

  • Turn the power up - a LOT
  • Turn the wire speed up even more of a lot
  • 12 ish for the flow, if you can get a Argon guage unit twin guage and flow meter as you need to be certain flow is accurate
  • Stainless wire brush the ali
  • PRAY

I have tried doing this on my machine, the welds looked messy, nothing like a nice tig weld :(

The mess it all makes is dreadfull, and the wire can jam really easy in the rollers, with the wire speed high the mess generated is huge and fast :(

I tried a mates spool on gun unit, welds just as horrible, and wire jams far less, but even his welds looked pants

Today I have been on day off, funnily enough playing with a AC DC EWM Triton 220 TIG Machine maybe up for sale shortly - very nice, amazing how pulse makes my AC Welds about 300% better :lol:

Frankly Ali MIG is not nice pretty or that good a option, it will do at a push, their are now AlI Migs (Single Phase) coming on the market called synergic, huge improvement, but still not the same as a nice TIG weld and horrendously spendy. May pay you if you have a set amount of work needing doing to give it to a pro with some money and get a reaaly good job back ?


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Thanks for the advice Nige,

May pay you if you have a set amount of work needing doing to give it to a pro with some money and get a reaaly good job back ?

Not an option, I'm skint :(. My time is (relatively) free so i can afford to practice. Also, the roof would require getting someone to come here to do the work, and work alongside me as such, that'd be mega £££.

I've got a bit of time tomorrow, I'm going to have another hit at it and see how i get on.

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Today I have been on day off, funnily enough playing with a AC DC EWM Triton 220 TIG Machine maybe up for sale shortly - very nice, amazing how pulse makes my AC Welds about 300% better :lol:


we use EWM's at work Nige,

if u can afford one they're exellent machines

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Don't set the power to high, on my 170 oxford ( old but reliable :D ) i go for about 70 / 80 amps, wire speed is higher than when welding mild, nearly half as much again, gas is only a touch more than with mild, make sure the work piece is cleaned immediately before beginning to weld preferably with a ss brush, for some reason the weld will sometimes pop and spit a little before creating a pool, so you may want to start a little further away from the area to weld, don't try to weave just drag the pool along ( quickly), if you can see the wire penetrating deeply you may have air in the mix, either from to much gas flow ( dragging air like a vortex ) or not enough gas, pay attention to what you can hear should sound consistent.

The welds you've done actually look quite good, using the steel backer will help with sags and holes, keep it up!

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Having read about 'smut' :unsure: , Today i had another go, this time cranking the gas up to about 20lpm. What a difference, the weld pool is a lot more stable and there's a lot less mess to clean up afterwards. wire speed has gone up a tad to get the weld pool happy.

The following are all seam welds, rather than stop-start. Bear in mind I'm left handed (i.e. welding left to right), each weld starts with a tack, so i can then use both hands with the torch. Also, it's worth saying i think the camera, the flash particularly, is a little harsh, I tried taking pictures without the flash but they are mostly blurred.

A start, granted not a super one, but better than last time.


A more constant bead, the rippling is not as harsh as it looks.


These two pictures give a different angle



Another one


I was pretty happy with them, so i went back to RR roof to try joints on that. Throughout this, it's become very apparent why TIG welders like their foot pedals, the heat in the metal changes the weld considerably, the tack and start of the weld are very cold, and by the time i'd welded 1 - 2 inches, i had to crack along at a pace to keep the weld from melting through.


Practice is shortening the time it takes to get the bead sorted, more work to do though


Here is the same picture, sans flash, i think it really does show it in a different light. the tack is clearly visible seperately on the left.


This picture shows trouble starting, then an alright bit, then a second pass at the end where i'd blown through (going too slow).


I'm starting to run out of offcuts of RR, and i'm getting bored of welding on the bench, so i'm hopefully going to start on the RR itself soon. the rear doors have the door-handle holes to fill in, then it's the roof, which is going to be hard work.

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