Aluminium Mig Welding Wire

What is the difference between 4043 and 5356 alumimium MIG welding wire?

• 4043 aluminium MIG wire offers a aesthetically pleasing finish, with lower susceptibility to cracking, it's efficient weld pool making it ideal for point of sale & general fabrications.
• 5356 aluminum wire has a higher tensile strength, better corrosion resistance, superior anodizing colour matching and is harder than 4043, which improves feed-ability.
• 4043 MIG wire is an aluminium filler alloy which contains 5% silicone, whilst 5356 contains 5% magnesium. The former is most suited to service temperatures over 150 degrees and the latter is best used for temperatures far below this level of heat – the magnesium compounds which it contains will not stand up to intense temperatures.
  
• 4043 wire tends to produces a decreased amount of spatter, and less smut. Yet, it is worth considering the fact that the 4043 wire has a lower level of ductility than the 5356 wire.

What changes are required to MIG set up when welding aluminium?

• Change your steel torch liner to PTFE to prevent sticking.
• Switch the contact tip to the aluminium variety, this compensates for expansion.
• As aluminium is softer, replace V grooved drive rollers with U shaped ones to assist feed-ability. 
• Aluminium welding demands pure argon shielding gas rather than an argon mix.

For light to medium duty welding of aluminium, we would recommend a pulse MIG, such as Miller's Migmatic 300iP. A pulse synergic MIG will offer you easy set up, lower heat input, a reduction in spatter & welding fume. For more heavy duty fabrications, you need to consider a push-pull system coupled to a pulse MIG inverter power source.

What are the advantages of push-pull MIG when welding aluminium ?

• Enhanced un-interrupted wire feeding with twin syncronized motors in the feed unit & MIG torch
• More reachability with torches up to 10 metres long, allowing for welding inside a trailer or structure.
• Adjustable wire feed speed from the torch, meaning the operator doesn't need to return to the MIG power source & feeder
• A high level of productivity against conventional feeding or spool on guns.

Why is MIG welding aluminium more difficult than mild steel?

• Aluminium is trickier to weld than steel, as it is very conductive and has a low melting point.
• To MIG weld aluminium effectively, hold the torch vertically & push away from you rather pull. This will offer a greater opportunity for the argon shielding gas to do it's job & give you a neater looking weld. Typically, you need to increase your wire speed & travel quicker too.
• Any oxide must be removed from the material afterwards with a stainless steel wire brush, rather a steel one, as steel filings from other jobs could contaminate the workpiece.