Informational Guide

How To Mig Weld Aluminum

Learn how to MIG weld aluminum with our complete guide. Beginners can master the techniques of professionals by following these steps.

MIG welding is so simple that even a beginner can do it. If you aren't sure how to MIG weld aluminum, we will give you the steps you need to get started.

Our comprehensive guide shows you how to weld aluminum with a MIG welder, how to set up an aluminum MIG welder, and more. With the best welders at your disposal, there’s no limit to the jobs you can perform.

Is Welding Aluminum Difficult? The Properties of Aluminum

Aluminum isn’t an easy metal to weld with because it requires more heat than welding mild steel. However, you can learn how to weld thin aluminum with a MIG machine.

The minimum thickness aluminum you want to weld with the best MIG welder is between 14 and 18 gauge. You should do anything thinner than that with a TIG welder for aluminum.

Aluminum MIG Welding Setup & Tips For Beginners

Consider material thickness

Many of the best MIG welders for beginners will handle aluminum to a certain thickness, but anything less than 14-18 gauge should be done with a TIG welder instead.

Clean Prior to Welding - Oxide Removal

Before you learn how to weld cast aluminum with MIG, you must remove the oxide from the metal. Oxide has twice the melting temperature of your aluminum. If you don't remove it, the joints aren't going to fuse correctly. Just use an aluminum wire brush to clean your material.

Choose the right gas mixture

Aluminum welding requires pure argon shielding gas, unlike the C25 gas used for welding mild steel. If you are working with a thick aluminum, you might prefer using 25-75% added helium to the mixture.

Spray Transfer Process

Spray transfer is the smooth transmission of molten metal droplets from the electrode to the molten pool. To do this, you need a lot of heat, and it can be difficult to control, so you don’t want to work with thick materials.

Travel Speed

When you learn how to set up a MIG welder to weld aluminum, make sure you use the same voltage as with mild steel but double the travel speed.

Spool Gun & Wire Feeding Options

It’s important to learn how to MIG weld aluminum with a spool gun. With a spool gun, you eliminate the birdnesting effect of the wires, but the push-pull system is also beneficial when you must weld far from a power source.

Choosing the Right Filler Material

If you want to know how to set up a MIG welder for aluminum, you need to evaluate what filler material to use. Investigate what alloy the base aluminum is using and what conditions your product will be subjected to. The two most popular filler wires are ER4043 and ER5356.

Current & Polarity Setting

If you use your MIG welder with flux core wire and the wrong polarity, you could end up with a lot of spatter. To avoid this, make sure your polarity setting is changed from solid wire to flux core wire.

Aluminum MIG Welding Techniques: Best Methods Discussed

Here are a few aluminum welding techniques for the beginner.

  1. 1
    Your push travel angle should be 10- to 15-degrees. Make sure the nozzle and tip are pointed in the direction of travel. If you are pulling, it will produce dirty welds that are porous.
  2. 2
    Keep the appropriate tip-to-work distance, allowing the contact tip to be recessed 1/8-inch within the nozzle.
  3. 3
    If you hold the tip too close, you could create burning and feeding troubles.
  4. 4
    Avoid using large weave beads. If you need a larger weld, make multiple passes with straight beads.
  5. 5
    Increase the torch travel speed if the base material becomes too heated.

Here’s a helpful ‘how to’ video if you need more guidance.

Common Challenges When MIG Welding Aluminum

Burn-through

  • Avoid melt through by increasing travel speed to create shorter welds.
  • Spread out the heat by moving around more.
  • Use a thicker material or change the joint design.
  • Switch to TIG welding.
  • Reduce or eliminate the gaps.

Dirty welds

  • Switch to a push angle.
  • Increase voltage for spray transfer.
  • Clean the base metal properly.
  • Ensure you are using the correct shielding gas, along with the right wire alloy.

Wrong machine settings

  • Read the manual to your MIG welder to ensure you have everything set up correctly.
  • Fine-tune the settings for your work.

Wire burns

  • Maintain an appropriate tip-to-work ratio
  • Ensure all of your equipment is appropriate, including the drive rolls, gun liner, and contact tip size.

Wire birdnests

  • Avoid piling by adjusting drive roll tension.
  • Ensure drive rolls are compatible with wire diameter.
  • Replace the contact tip.
  • Inspect pressure adjustment on the spool gun.

MIG Welding Safety Precautions

Welding is a dangerous activity, with 1 out of 250 construction workers suffering fatal injuries as a result of a welding accident. Here are a few safety tips you should always follow when welding.

  • Keep the machine on the floor of a welding booth or in a dry location.
  • Maintain adequate lighting in your work area.
  • Check for gas leaks often.
  • Work in a well-ventilated area and use a respirator.
  • Safely store all flammable materials.
  • Maintain all welding equipment regularly.
  • Always wear proper welding gear, including eye protection and special clothing.
  • Keep a first aid kit and a fire extinguisher nearby.

Different Aluminum MIG Welding Conditions

How to weld cast aluminum with MIG

It’s often better to go with a TIG welder for this work. Otherwise, if you get the material too hot, it might collapse. But, if it doesn’t get hot enough, you won’t produce a solid weld.

How to MIG weld aluminum with a spool gun

With the spool gun, you can feed the wire by short distances, making this a great option if you don’t have to work over long distances. Use the spool gun to eliminate the challenge and feed the aluminum efficiently.

How to MIG weld aluminum without a spool gun

You can learn how to MIG weld aluminum without spool gun by loosening the spring tension to keep the wire from snapping as it goes through the feed rollers. Keep the liner and lead straight to avoid any kinking.

How to MIG weld aluminum without gas

Can you MIG weld aluminum without gas? You could weld the aluminum in a vacuum chamber, but it exposes the metal to oxygen that’s circulating around the workspace, creating a less reliable weld.

How to weld aluminum with a Lincoln MIG welder

Lincoln Electric has a database full of the manuals you need to operate one of the company’s welders. We advise you to read the manual for a better understanding of how your machine works.

How to MIG weld thin aluminum

You want to use argon shielding gas when working with thin aluminum. Helium blends are only useful with thicker sections, so the mixture should be avoided.

People Also Ask (FAQs)

Can I weld aluminum with a wire feed welder? What are the basic steps?

You can, but aluminum is extremely conductive, which causes trouble at lower voltages. Therefore, it’s important to prepare your materials for success. For example, if your welder uses a steel wire liner, you should replace it with Teflon or plastic.

Is brazing aluminum as strong as welding?

A brazed joint is often stronger than welding because it is done at lower temperatures, and the base metals never melt.

What kind of welder do you need for aluminum?

Ideally, you want to use a TIG welder with aluminum. It’s the choice of most professionals. However, MIG machines can get the job done with the right materials.

What kind of gas do you use for MIG welding aluminum?

Most times, you will want to use an argon shielding gas, but there are instances when a helium mixture is needed.

What MIG flow rate should be used when welding aluminum?

Flow rates between 20 and 30 cubic feet per hour are recommended.

What causes excessive spatter in MIG welding?

Excessive spatter could be caused by incorrect parameters, an erratic arc, user error, dirt, or low-quality consumables.

How many amps does it take to weld aluminum?

For every 0.001-inch of metal that you need to melt, you require about an amp of power. That would mean a 1/8-inch aluminum sheet would require 125 amps of welding power.

What polarity is used for MIG welding aluminum?

Aluminum welding with a MIG machine requires DCEP (Direct Current Electrode Positive). This reverse polarity setting allows the electrons to move from the machine through the ground cable and then back into the gun.

Conclusion

If you want to weld aluminum with a MIG welder, our beginners' guide should provide the information you need to get started. Choose the best materials and get to work on your next project.

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