Mig Welding Aluminum

A continuous voltage control

  1. Push dont Pull.  Always Push the puddle when possible for a cleaner soot free weld.
  2. Use a longer stickout. Mig welding Aluminum uses something called spray transfer. Thats a technical way of saying the wire never really reaches the puddle. So a longer stickout is needed to avoid burnbacks.
  3. Use Argon and not an Argon C02 mix.  Argon or Argon Helium is the ticket.  Dont use argon/c02 unless you just want to do a lot of cussing

Now lets talk about some tips for machine and spool gun settings:

What Type of Shielding Gas is Required?
MIG welding aluminum is different than welding steel when it comes to shielding gas requirements. For aluminum, 100 percent argon is the gas of choice, whereas steel welding calls for a mixed gas or 100 percent CO2 gas. The good news is that no special equipment is needed – your existing regulators (with the exception of CO2 regulators) and gas hoses can be used for both pure blends and mixed gases.

What Polarity Setting is Needed?
All MIG welding, including on aluminum materials, requires electrode positive polarity, while flux-cored processes typically use electrode negative. If you are switching your wire feed welder between processes, make sure to switch your polarity. This is a common mistake that many beginning welders make.

\r\n\r\n\r\nWelding Techniques

– Hook spoolgun to the positive stud on the power supply.

– For MIG welding aluminum you need to use a 10 to 15 degree push travel angle (tip and nozzle pointed in the direction of travel). (See Figure 1)

Figure 1:  Gun Techniques

– Pulling or using a drag angle will produce porous, dirty welds because of lack of gas coverage.

– Spray transfer is the desired mode of metal transfer for welding aluminum. The spray transfer is a very smooth transfer of molten metal droplets from the end of the electrode to the molten pool. The droplets crossing the arc are smaller in diameter than the electrode. There is no short-circuiting in spray transfer. With spray transfer the deposition rate and efficiency is relatively high. The arc is very smooth, stable, and stiff and the weld bead has a nice appearance and a good wash into the sides. In the spray transfer a large amount of heat is involved which creates a large weld pool with good penetration that can be difficult to control and can not be used on materials thinner than 14 Ga. This transfer will produce a hissing sound, and no spatter.

– The short arc transfer on aluminum produces poor cleaning action, poor tie in at the edges of the weld, and large amounts of spatter and smoke.

– Maintain a tip to work distance, and have the contact tip recessed approximately 1/8? inside the nozzle if possible. (See Figure 2)

Figure 2:  Gun and Weld area

Common Problems/Troubleshooting

Dirty Welds

1. Use push angle instead of drag technique.

2. Increase voltage to get into spray transfer.

3. Use proper base metal cleaning techniques (Stainless Steel Brush).

4. Check for proper shielding gas and wire alloy type.

  • new al welder

    we r welding 4″ sch 80 aluminum 500 kv high voltage round bus.. what cleaning solvents or technich should we use prior to welding..what size ss wire wheel ( ex 014, 020 ) for our disk grinder should we use for cleaning our welds?

  • human race

    To get a 1/4″ bead when welding 1/2″ to 1/2″ lap joint what size of filler rod should be used ( aluminum alloy) including it’s heat and speed.