Several metallic elements are present in our earth’s crust, and one of them is aluminum. It is unique because it’s not in metallic form but different rocks and its chemical activity makes it soft.
The metal has many applications, but adding alloys is required to increase its strength. Aluminum is a challenging metal to weld as its more prone to heat and distortion.
However, using proper techniques and equipment, you can easily get over these issues by using a MIG welder to weld aluminum.
Welding Aluminum with a MIG Welder
Following are the steps that you need to follow:
MIG welding aluminum is challenging as it requires more heat( 21-24 volts) than mild steel. A MIG welder is capable of welding aluminum thickness of 14 gauge and heavier, depending on the output capacity of a welder.
However, If you intend to weld metal with a thickness of less than 14 gauge(.74inch), you’ll need an AC TIG welder.
2:Cleaning the Metal( Oxidation Removal)
I suggest you remove the oxidization layer usually formed on the surface, as this oxidized layer has more melting temperature than aluminum itself, so its elimination is necessary for forming a stronger weld joint.
The weld piece can be easily cleaned using a steel or aluminum wire brush. However, brushing with aluminum wire is more recommended as steel contaminates the weld.
All you are supposed to do is clean the joint using an aluminum brush that you will weld, and you are on the move.
Also Read: How to Setup MIG Welder for Aluminum Welding
3: Choosing the Right Shielding Gas
Aluminum is non-ferrous in nature, and for MIG welding aluminum, you should use 100% pure argon gas. I recommend you set the flow rate at 25-35 cubic feet per hour.
However, when welding heavier gauge aluminum (1/2in or more ), helium ranging from 25-75 percent is mixed with argon, as the argon alone can’t offer the required penetration.
4:Spray Transfer Mode
The process smoothly transfers melted droplets from the electrode end to the weld pool. The melted droplets flowing through the arc are smaller than the electrode.
We suggest you use the same voltage settings with mild steel but double the spray travel speed. Though, in the beginning, It might be uncomfortable to move your MIG gun fast, you get used to it over time.
Besides, short circuits do not exist in spray transfer and have higher efficiency and deposition rate. However, spray transfer is not suitable for metals with thicknesses of less than 14 gauge cause this transfer mode involves a high heat amount, creating a large weld pool.
5:Using the Spool Gun
When MIG welding aluminum with a wire-fed welder, you can’t simply put the aluminum wire drive roll into your machine. Because the aluminum wire is soft enough to create a bird’s nest inside the roll, we use spool guns to prevent the wire from tangling.
This user-friendly technique allows you to work where the power source is away.
Remember, when MIG welding aluminum, always use the push welding direction rather than the pull. Pushing makes sure that the weld pool is covered sufficiently with shielding gas. Moreover, pushing helps produce a wider and flatter bead with less penetration.
6:Filler Metal Selection
You should know the alloy family of base aluminum. However, ER4043 & ER5356 are the most commonly used aluminum filler wires. You can buy these wires from any local welding store around your house.
The welding equipment listed below is not required for all welding operations. However, I suggest you use welding safety gear to avoid any accidents.