Thread: MIG welding Aluminium

Forget the god awful zinc sticks flogged as some wonderful innovation at the various field days!
If one uses 5183 mig wire rather than 5356 you will find feed problems are minimised.
I definitely second the fact that there is more that the salesman don't tell you about welding aluminium with a mig than what they do, (how many salesmen can actually weld?).
150A would be absolute rock bottom amperage for a mig used on aluminium and 200 is a more practical minimum - first rule of welding aluminium is hot and quick, come to think of it, that's not a bad rule for most mig welding, but with aluminium it is imperative.
I would also like to mention that aluminium has a rather higher degree of fume production than steel and also the arc burn that you will get from aluminium and stainless is far worse than if you suffer it from steel.
It definately is not a beginners metal to weld.

Just to give some idea of equipment involved....

At work I use a 3 phase pulse MIG (ESAB MA60) and occasionally have to weld 3mm thick ally corner to corner joints.

My wire is 5356 @ 1.2mm thick. I would not consider using smaller diameter,as the wire feed issues become to problematic.

This machine works well here, although the machine is set quite low and I have to go really fast to prevent blowing through.

Aluminium really works well with pulse MIGs and high power. As the other guys have mentioned, it is not really in the field of the home handyman as a beginner or without suitable equipment.

I feel the best option for home use on reasonably thin stuff is with TIG. The TIG needs to have an AC output and it also requires a different type of tungsten electrode to the normal one. But TIG is an art in itself to use properly with aluminium, the biggest thing to learn is when your parent metal is overheating and about to blow away....

Plate aluminium and extruded aluminium also require very different levels of heat input. I usually have to weld a 2mm thick extruded channel to 6mm thick checker plate. Am mastering the technique using about 160 amps.

But when I weld 10mm thick extruded flat bar to the same plate, I have to double my power to get a good fillet weld. Otherwise the arc will not penetrate the extruded section. Definitely 3 phase power stuff here.

There are also several different types of shielding gases available which also affects how the arc heat and properties work.