Arc welding alloy tube.

[benji]

I'm scoping out the idea of making my own roof rack from alloy tube.

I've a cheap arc welder and can weld mild steel down to 1.5mm quite well.

What I'm wondering is, is it possible to weld alluminium on an arc, and how tricky is it?

Obviously a mig would be better, but i don't have access to one.



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[oldyella 76]

Benxi, I am in Kunnurra at the moment but if you are not in a hurry I can do it when I get home, as we can mig it for you or teach you and you can use our gear. But I will not be home for another 6 weeks.
Lindsay.
P.S will be bush for 2 weeks till Broome.

[weeds]

I haven't heard of arc welding aluminum......TIG is another option if your power source allows

[rick130]

I haven't heard of arc welding aluminum......TIG is another option if your power source allows

Except you need an AC TIG and a lot of power, an inverter DC TIG won't do it.

[incisor]

Except you need an AC TIG and a lot of power, an inverter DC TIG won't do it.

god bless the old motor driven dc..

https://www.aulro.com/afvb/images/imported/2015/07/308.jpg


can hear it whining in my sleep :p

[rick130]

god bless the old motor driven dc..

https://www.aulro.com/afvb/images/imported/2015/07/308.jpg


can hear it whining in my sleep [emoji14]
Geez, that's older than me ! :D

[bee utey]

As a young lad I once worked in a shop that fabricated aluminium fire truck bodies and they used MIG quite extensively for materials 6mm thick and over. I used one of these machines to build prototype sorting machines and it was quite difficult to achieve the fine balance between the weld bead just falling off and the entire joint turn into a puddle. The dedicated ally MIGs were pretty powerful machines too and never did anything else. Cleanliness was absolutely essential.

Anything thinner, say 3-4mm, was done with a TIG welder with a foot pedal for current control. This was quite easy to use as you could ramp the current up and down as your weld changed orientation. I wouldn't like to do a roof rack as my first project with anything less than a top quality TIG after using that machine. It was great. No idea now what brand it was.

[Toxic_Avenger]

Pro weld do a 4043 aluminium rod, I've not had first hand experience with them, but know they're out there.
MMA process for aluminium is not a common process, as others say best to get a mig setup for aluminum, or an ac tig.

[dan007]

Just spoke to our welding inspection team at work(one has had 20 years Ali welding)
His response the rods are too cold. To hard to pool. And are not very good.
He said like trying to weld stick with wet 1.2 mm rods on 5mm gal pipe.
Can be done but result only good for the back paddock on the farm.
Un quote

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[Toxic_Avenger]

Hi Dan,
I knew this, but the reason they exist is for the bloke trying to do a $20 fix for a $500 problem (which ends up costing more in the long run anyway) ;)

I supplied a customer at work with a few packs- he was hoping to avoid buying a mig, but ended up caving in the end:twisted:

[123rover50]

Except you need an AC TIG and a lot of power, an inverter DC TIG won't do it.

Say for welding from .5 up to 2mm ally sheet, what would you reccomend?
What are inverter DC TIG,s good for?
What about thishttp://www.ebay.com.au/itm/NEW-ROSSI-Welder-Inverter-Plasma-Cutter-4in1-Welding-Machine-AC-DC-TIG-ARC-Stick-/160861426342?pt=LH_DefaultDomain_15&hash=item25741692a6


Keith

[123rover50]

I have been doing some reading.
Perhaps this would be better.
Boswell 200Amp AC DC Inverter TIG ARC Aluminum Welder | eBay (http://www.ebay.com.au/itm/270507388880?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

K

[rick130]

Hi Keith, I'm not a welders backside, but have been lucky to work with a couple of brilliant welders over the years. :D

I can braze till the cows come home, and am passable at oxy welding, if I've been practicing but I've mostly had access to brilliant welders, the type of blokes that make those incredibly neat, even TIG beads that look more like art than an industrial process of joining metals.

DC TIG's are great for steel and particularly stainless, especially if it has an adjustable pulse setting.

[123rover50]

Yes, I am just a farm welder using stick and gas fusion.
Reading up on TIG as I would like one for thin ally and it seems you need AC for it cleans up the ally as it goes. Not so much need for the SS wire brush.
That last I linked to seems OK and I was just asking for comments.
Not meaning to hijack the thread but the discussion I hope will help the OP.

K

[Blknight.aus]

Say for welding from .5 up to 2mm ally sheet, what would you reccomend?
What are inverter DC TIG,s good for?
What about thishttp://www.ebay.com.au/itm/NEW-ROSSI-Welder-Inverter-Plasma-Cutter-4in1-Welding-Machine-AC-DC-TIG-ARC-Stick-/160861426342?pt=LH_DefaultDomain_15&hash=item25741692a6


Keith

sikaflex.....if you're just bonding ally sheet to a frame a nice clean joint and a bead of that stuff with good clamping while it cures...

[SouthOz]

Im keen to give some of these a try. Not on a roof rack maybe unless it had lots of bracing.

https://www.youtube.com/watch?v=yqkceLrH9Ao

https://www.youtube.com/watch?v=CJ42scaWFnw

Dave

[rick130]

As that second vid says, it's actually hard brazing, not welding.

I've brazed aluminium, you need the right flux and the heat is directed by capillary action, if the flame hits the flux it oxidises and it's game over.

You can fusing weld aluminium with an oxy/acetylene blowpipe, I've seen it done and it looked just like a MIG bead, again you need special flux and picking the puddle before it collapses is an art.
Ideally you use a special lens in your welding goggles too, again so you can pick the puddle before it all goes ta ta's.

[123rover50]

Yes I use Sikaflex like that a lot, but I was meaning edge to edge.

Woops, I should have quoted Blknight.
Its in reply to his post.

[MattyGM]

The reason you need to use AC for welding aluminium is that the aluminium oxide melts at a much higher temperature than aluminium metal.

The AC pulsing/swinging from +ve to -ve burns the aluminium oxide from the surface of the metal allowing it to be melted cleanly and at a far lower temperature than if the oxide remained on the surface. This works even better with an argon shield which prevents the molten metal re-oxidising whilst welding.

That is why TIG or MIG are the preferred methods for welding aluminium.

Arc welding rods need to their flux to prevent oxidisation of the molten metal.

As mentioned previously by Rick, it is possible, but difficult, to oxy acetylene weld certain types of aluminium if you clean off the aluminium oxide, flux and then immediately weld it (usually cheap grades of alloys as you would find in teapots etc).

Certain series aluminium alloys are more weld-able than others. From memory all of the 1000 and most of the 4000, 5000, 6000 and some of the 7000 series alloys are readily weld-able.

Always use a stainless steel wire brush to clean your material when welding aluminium.

Hope this helps :)

[Judo]

Im keen to give some of these a try. Not on a roof rack maybe unless it had lots of bracing.

https://www.youtube.com/watch?v=yqkceLrH9Ao

https://www.youtube.com/watch?v=CJ42scaWFnw

Dave
I bought some of these rods and gave them a go. No way I would use them for anything structural like a roof rack but I did manage to get a good join with it properly brushed clean and the right temperature (quite hot and clean).

Freshly joined:

https://www.aulro.com/afvb/images/imported/2015/07/240.jpg

But this came apart with a bit of force from a hammer.

https://www.aulro.com/afvb/images/imported/2015/07/241.jpg

I did it again but went for a bit more heat and more liberal application of rod and took to it with the hammer more and more...

https://www.aulro.com/afvb/images/imported/2015/07/242.jpg
https://www.aulro.com/afvb/images/imported/2015/07/243.jpg
https://www.aulro.com/afvb/images/imported/2015/07/244.jpg

I couldn't hit the lump any harder without knocking it out of the vice, but the join was still good. So that was solid, I couldn't break it. Difficult to tell from looking at it whether you had a good join though. My better "looking" join was the weaker one. If you spent some more time on it you could probably repeat some good joins. I still wouldn't trust it for anything serious, but there is definitely some cases it would be OK.

I was using MAPP gas but propane would be fine I think.

[Didge]

As per Bee utey's comments - very difficult to weld ally. Unless you plan on doing a lot of it, I'd suggest saving a few penny's and paying someone to do it professionally. It's cheaper than you might think if you've got it prefabricated and maybe clamped together.

ps great photos Justin - what sort of camera are you using?

[Judo]

iPhone 6+ under shed fluro lights. lol

[Didge]

You're kidding! Sensational clarity. Funnily enough, I did read a report a short while back that stated one of Sony's phones was a better camera than one of its flagship cameras.