Mig welder for aluminium

[Danny1107]

Got a few small projects that require me to weld aluminium, I'm planning on buying a MIG welder (budget can't stretch to a TIG at the moment) Am I right in thinking any gassed MIG will do the job with the right wire (4043?)

I'm currently looking at a MightyMig 150XT, would this do the job? Obviously I'll be practising before hand as I've never welded aluminium before.

The welder is mostly going to be used for steel but obviously wanting to weld aluminium too, I have suggested making said project out of steel but my dad (who it is for) wants it in aluminium to keep the weight down, thickness will be 2.5mm

If the MightyMig 150XT is up for the job I may go collect it tomorrow, also is it difficult to convert it from disposable bottles to refillable? (I don't imagine it will be too hard, just a change of regulator?)

 

[norlander]

http://www.mig-welding.co.uk/aluminium-welding.htm -its in MIG on the green bar at the top of the page. Disposable bottles use a tap-it can hardly be called a regulator imho-if you have to start out with dispo bottles get them and the regulator from weldequip-again see top of page.Proper bottles have gauges to show bottle pressure/content and flow rate.
Its not difficult to change.
There is some info on here re bottle safety-so have a search on that-gas bottle handling and use gets taken for granted.

http://www.mig-welding.co.uk/forum/threads/shielding-gas-safety.9315/ remembered where it was. I have one issue with the advice on there and its using soapy water to test for leaks. That is ok for the inert gas that most DIYers use, but I would not do that on an oxygen set up-so I never do it-I always use a can of proper leak detector from a welding supplies outlet.You may branch into oxy kit later and use soapy water or spit out of habit.
Grease/fat/oil can light up an oxy cylinder under certain circumstances.

 

[Jan]

As long as the output (neither too many nor too few amps) of the welder is correct for the thickness of metal being welded then any decent MIG box will do the job.

However It's better to have a spool gun for aluminium as the liner to the gun will soon be seriously contaminated by any type of steel welding wire. Once this hits the weld puddle while welding ally it will corrupt the weld. Don't forget that you can only weld ally with pure argon and definitely not with any shielding gas that contains CO2 or O2!

 

[Richard.]

If you are welding a lot of Ali with a mig it's well worth getting the correct internals. Teflon liner, plastic tight feed guides, v shape rollers etc. ali is very soft and the slightest resistance while feeding through a mig will bend it causing hours of frustration.

 

[Ed.]

As Jan said, If you want to weld steel and also aluminium then you will also need two different gas bottles. You cannot use the steel gas mix on Ally. also you would most likely want to use a thicker ally wire as the thinner stuff will bird nest easily.

 

[flightrisk]

You really do need the Teflon liner. If there is any chance of internal arcing within the steel liner the aluminium wire just blows to bits.
Also, make sure your contact tip is 0.2mm bigger than your wire dia. Aluminium wire is inconsistent in size compared to steel. Any resistance of movement will result in bunching back at the rollers.
Set you rollers so they only just grab the wire. That way they will tend to slip rather than push the wire to bunch up if there is a problem at the gun end.
4043 is soft material. It's great for flowing and looks good however, it can be a nightmare in a MIG set up unless you have a spool gun or in my case a push pull gun set up (fronios TPS). Go with 5356. It's about %5 mg and is reasonably hard. Run pure Argon with a good amount of flow. You will always get plenty of black soot but that will clean away easily.
Lastly, start your settings with a slight bias to starving the weld of wire and ramping up. Be prepared to throw out a lot of wire from bunch ups. It's good to have a beer and be relaxed as it can be very frustrating to start with!

 

[Richard.]

Hmm i was told i need a U roller for ali as a V will distort it

Your right that's what I meant it is a U shape for Ali V shape for solid and nurled for flux core. My mix up. Cheers