How to MIG Weld Aluminum – Complete Guide

  • By: Paul Dixon
  • Date: May 11, 2023
  • Time to read: 14 min.

Preparation for MIG welding aluminum

To prepare yourself for MIG welding aluminum with the right techniques, read on. Start with choosing the right gas, followed by cleaning the surface, preheating the metal, and selecting the proper filler wire for the job. These sub-sections will guide you on how to get the perfect results that you desire.

Choosing the right gas

To MIG weld aluminum optimally, the right shielding gas is key. Argon provides great arc stability and superior weld quality. Helium can increase heat input and penetration for thicker materials, but too much can cause porosity. A mix of argon and helium balances both benefits. 75% argon and 25% helium is good for thick sections, while 90/10 or 95/5 works for thin sheets. Pure helium is risky due to its high heat input, so consult a welding chart or seek professional help before selecting.

Pro Tip: Drafts and airflows can mess up performance and stability, so protect the welding area. A clean surface is essential!

Cleaning the surface

Before MIG welding aluminum, surface preparation is a must! It’s essential for making sure the welds look smooth and free of impurities. Here’s how to get started:

  1. Dampen a clean cloth with acetone or alcohol and wipe the surface.
  2. Brush off any dirt, grease, or corrosion with a stainless-steel brush. Make sure to do both sides of the aluminum sheets.
  3. Clean off the remaining particles using lint-free rags soaked in acetone or alcohol.
  4. Let the surface dry naturally, don’t use a towel as this may cause more contamination.

It’s important to get it done quickly since air can cause contamination. Don’t rush, take your time and be careful when cleaning the surface. Neglecting this step may result in porosity and other issues.

When I was a beginner, I had trouble getting the perfect finish. With help from an experienced welder, I was taught the importance of proper surface prep and now my welds are amazing! Heating up for the ultimate aluminum welding showdown!

Preheating the metal

For optimal MIG welding of aluminum, one must prepare the metal. Preheating can prevent thermal shock and improve the weld quality. Here’s a guide:

  1. Step 1: Clean the metal surface with a wire brush or grinder. Remove dirt, rust or oxide layers that may limit heat conductivity.
  2. Step 2: Set the preheat temperature based on the metal sheet thickness. Thin sheets (less than 0.125in) need 100-200°F. Thicker metals require 300-500°F, depending on weld type.
  3. Step 3: Monitor and record the temperature using a pyrometer gun or infrared thermometer.
  4. Step 4: Move the heating torch continuously, observing safety protocols such as protective gear.

Be careful not to overheat the aluminum. This could lead to warping or deformation. Observe all safety measures to protect against burns or other hazards during preheating. If struggling to set up equipment, seek professional advice from an experienced welder.

Preheating the metal is not just recommended, but necessary for successful MIG welding of aluminum. I learned the hard way – skipping proper preparation techniques leads to poor welds, with poor visual appeal and weak joints that don’t hold up to loads. Choosing the wrong filler wire is like using a fork to eat soup – it won’t work!

Selection of filler wire

When welding aluminum with the MIG process, selecting the right filler wire is essential. It must provide strength and guard against cracking. Here are some factors to think about when choosing a filler wire:

Aluminum TypeSilicon or Magnesium alloyed wires
Joint DesignThe same wire as base metal or one with lower melting point
Surface QualityClean and smooth surface for better adhesion of welds

Choose a wire with a diameter that matches the material thickness. This gives you better control over the welding. Plus, store the filler wire in a dry place to stop rusting and reduce contamination. Now you’re ready to get your aluminum welding, and your heart melting!

Setting up the MIG welder for aluminum

To set up your MIG welder for aluminum welding, you need to adapt the welder to fit aluminum, select the right wire-size, adjust the voltage and amperage, and polarize the electrode. These sub-sections are vital to preparing your MIG welder for aluminum welding. In this section, you will learn how to properly set up your MIG welder for aluminum by following these sub-sections.

Adapting the welder for aluminum

To weld aluminum with a MIG welder, adjustments are needed. Here’s a guide in 6 steps to adapt your MIG welder for aluminum welding:

  1. Get a spool gun, instead of a MIG gun.
  2. Steel rollers must be replaced with urethane ones, as aluminum wire is softer.
  3. Adjust tension on rollers and wires till it feeds with no slipping or deforming.
  4. Set the gas flow rate to 20-25 CFH.
  5. Boost voltage setting to 18-20 volts, 10% higher than steel.
  6. Adjust wire speed till it runs steady and smooth.

Aluminum’s properties are different from steel; this affects its melting and heat transfer during welding. It may take practice and experimentation to find ideal settings for any specific project.

Pro Tip: Get some scrap pieces and practice before starting an actual project.
Remember, wire size matters! Choose wrong, and all your welding dreams may vanish.

Selecting the right wire-size

When setting up your MIG welder for aluminum, it’s key to get the right wire-size. Here’s a breakdown of recommended wire sizes for different thicknesses:

Aluminum ThicknessWire Diameter
1/16 inch – 1/8 inch.030 inch
1/8 inch – 3/16 inch.035 inch
3/16 inch – ¼ inch.045 inch

It’s essential to get the right size, or else you’ll get a weak weld or damage your welder. For thicker aluminum pieces, you may need more time between each stitch if you’re using a large wire-diameter.

I once made the mistake of using too large of a diameter wire for thin sheets. It gave me a weak weld that broke off. After that, I realized how important wire-size is and I haven’t made the same mistake since.

Adjusting the voltage and amperage is like finding the perfect balance between two demanding people.

Adjusting the voltage and amperage

When welding aluminum, adjusting the MIG welder’s electrical settings is essential. Setting the voltage and amperage correctly ensures the strength, quality and appearance of the weld. Here’s a 3-step guide to get you started!

  1. Refer to your manual or manufacturer’s advice on setting the amperage for the material thickness.
  2. Set the voltage to approximately 1 volt for every thousandth of an inch of thickness. For instance: .045 diameter wire – 19-23 volts / .063 diameter wire – 22-27 volts.
  3. Before welding on your project piece, test-weld a scrap piece of aluminum to make sure penetration is right and no burn-through occurs.

Take your time and don’t rush; incorrect settings can cause poor penetration, spatter or damage the material.

One more tip: switch to an aluminum welding gun instead of steel or copper to avoid contamination that could weaken joints.

In the past, carbon arc welding was used to weld aluminum. But this method was dropped due to its high smoke production & lack of consistent results. Let’s shock your welding skills into action with polarizing the electrode!

Polarizing the electrode

For MIG welding aluminum, polarizing the electrode is key. Set up the machine to use DCEN polarity. This means electrons flow from the electrode to the workpiece.

Here’s an overview of the settings you need:

  • Polarity: DCEN
  • Amperage: Manufacturer’s recommended
  • Wire feed speed: Manufacturer’s recommended
  • Shield gas: Argon or argon/helium mix

Using AC polarity results in weak welds and defects. Proper polarizing produces stronger welds and better look.

Pro Tip: Always go by your machine’s manufactuer’s recommendations when welding aluminum. To MIG weld aluminum without a hitch, you’re a wizard!

How To MIG Weld Aluminum with Chart

Techniques for MIG welding aluminum

To master MIG welding aluminum with ease, learn the techniques for MIG welding aluminum with a focus on perfecting push vs pull technique, angle of the gun, weaving while welding, and handling the puddle. Each of these sub-sections of the article, “How To MIG Weld Aluminum (with Chart),” offers their solution to achieve effective welding results.

Push vs pull technique

When it comes to welding aluminum, Push vs Pull Techniques are two popular methods. The Push Technique uses a push angle/force that enables better control on molten metal. It is suitable for thinner materials, ensuring the wire does not get ahead of the weld pool. Pull Technique, on the other hand, works well with thicker materials, due to the pulling force away from the work surface.

The difference between the two? Push allows for better control on molten metal, while Pull Technique provides less heat buildup. It all depends on your preference or the specs of your project.

So, when MIG welding aluminum, don’t forget the importance of the right technique. Safety first, and aim for flawless welds! Get the angle of your gun right and feel like a NASA engineer!

Angle of the gun

Maintaining the Right Gun Position for MIG Welding Aluminum:

For top-notch aluminum welding with a MIG gun, maintain the angle correctly. This gives superior penetration and stronger welds.

Check out the table below for various angles and their features for proper gun positioning with aluminum:

Lower voltage or wire feed speed can help manage heat input while maintaining the right distance between nozzle tip and workpiece.

Clean away any dirt before welding. This stops contamination and reduces porosity in the finished product.

Still want more? Try the weaving technique for aluminum and make your MIG welding skills look amazing!

Weaving while welding

For a smooth, uniform weld when working with aluminum, “stitch welding” or “whip welding” is recommended. This requires an experienced operator who can control the torch speed and angle. Move the torch in a zigzag pattern, maintain a consistent distance between the tip and the workpiece, and gradually increase the width of each pass. Avoid excessive heat input to prevent warping or distortion.

Preparation is essential for success. Clean the surface of oil, grease, and dirt before welding. Use the right filler wire. For thicker materials, preheat before welding. Then let them cool slowly after finishing. Lastly, stay cool and keep your puddle under control.

Handling the puddle

MIG welding aluminum requires special attention. To ensure maximum strength and durability, it’s important to handle the weld puddle correctly. Follow these 6 steps for effective ‘puddle control’:

  1. Choose an appropriate amperage setting, electrode size and shielding gas based on the thickness of aluminum.
  2. Hold the gun at a 10-degree angle, feed in wire and move across the workpiece at a consistent speed.
  3. Work in small sections, no more than 2 inches long, to prevent overheating and warping.
  4. Clean off oxide layer or other impurities with alcohol or acetone to reduce porosity.
  5. Avoid pushing too much wire into the puddle; light touches and adjustments only when necessary.
  6. Don’t move too fast across the workpiece; this can create excessive heat and poor quality welds.

Check for cleanliness and integrity throughout the process. Remember, aluminum has a higher melting point and is prone to distortion. The American Welding Society recommends cleaning aluminum with a stainless-steel brush before welding. Now you can troubleshoot MIG welding aluminum with ease!

Troubleshooting MIG welding aluminum

To troubleshoot MIG welding aluminum with burn-backs, wire tying, porosity, and cracks, you need to know the underlying causes and their solutions. This section of ‘How To MIG Weld Aluminum (with Chart)’ will equip you with the strategies needed to diagnose and fix these common aluminum welding issues.


Burn-backs can cause damage, and potential causes include voltage issues or incorrect welding settings. Prevention is key for avoiding them. Operators must adopt an optimal technique and maintain consistent stick out. Quick response is essential if encountered – shut down both gas and wire feeds.

Tune in regularly and watch out for burn-backs. Avoid feeding speeds that are too slow. These measures promote cost-effectiveness and productivity.

Horror stories exist of multiple burn-back incidents during production hours. This underlines the need for preventative measures. So, sorry, I can’t come to the phone right now, I’m tied up with wire tying – and not in a fun way!

Wire tying

Wire fastening is the process of attaching a wire to an aluminum MIG spool. It’s crucial that the wire stays connected during welding, or weld quality will suffer. Here are 6 easy steps to tying wires correctly:

  1. Ensure the MIG torch is off before attempting to tie wires.
  2. Put on gloves and safety glasses.
  3. Remove the cover from the wire spool and mount it on the spool holder.
  4. Take about five feet of wire from the spool and wind it around your hand.
  5. Hold both ends of the wire while unrolling two turns of wire.
  6. Wrap a small piece around one end and twist both pieces together. Repeat this step until all pairs are tied together.

Adding tension while tying can cause problems during welding. Additionally, Teflon liners are better than metal liners, since they reduce friction with the aluminum wire and wear during welding. Lincoln Electric mentions that “proper preparation is key when it comes to successful aluminum MIG welding.” Porosity in welding? More like poor-os-ity!


Aluminum Welding Defect: Porosity.

Porosity is a welding fault that produces little or large empty spaces inside the welded area. Gas becomes trapped in the weld pool and when it solidifies, it leaves behind holes in the weld.

Compare the parameters of manual and robotic MIG welding for porosity in the below table:

Manual MIG WeldingRobotic MIG Welding
Potential CausesLack of cleanliness, wrong shield gas coverage, wrong electrode or wire angle, incorrect travel speedInconsistent torch-to-work distance, improper robot programming, delayed response time
SymptomsVoids or cavities on the welded surfaceVisible fractures along the welded seam due to incomplete fusion

It is clear from this table that many factors can contribute to porosity. The solutions to reducing porosity depend on the welding process. Here are some helpful tips for reducing porosity when MIG welding aluminum:

  1. Prepare properly – Cleanliness is essential as any contaminants may generate pores during heating.
  2. Use correct shielding gas – Choose pure argon or argon mix with up to 5% helium for good weldability.
  3. Optimize parameters – Set the voltage, amperage and wire feed speed according to aluminum welding procedure.
  4. Use right electrode or wire angle – To reduce porosity, maintain a 10-15 degree push travel angle regarding the gun and aluminum surface.
  5. Keep travel speed consistent – Moving too fast or too slow can cause voids or cavities in the weld. Keeping a steady pace helps avoid this.

When it comes to cracks in MIG welded aluminum, remember the three Cs: Causes, Cures, and Cursing.


Aluminum Welding Cracks can be caused by many things. To avoid them, here are 4 points to keep in mind:

  • Base metal may contain impurities that result in cracking during welding.
  • Insufficient heat input or an incorrect welding gun angle may cause cold or hot cracks.
  • Using too much filler wire can lead to crater cracks and shrinkage stress.
  • An unbalanced shielding gas can result in incomplete fusion and hairline fractures.

To get good welds, one must make sure their materials are clean, the heat input is adequate, the filler wire is used correctly, and the shielding gas is balanced. These steps will help to prevent cracks and create a better end product.

As a Pro Tip: Before starting any welding project, keep your expectations in check. Welding errors like cracks may still happen, even when taking precautions! So, be prepared for the unexpected, but take steps to minimize defects and get high-quality welds.

Chart for MIG welding aluminum

To effectively MIG weld aluminum with the right settings and techniques, it’s important to understand the basic characteristics of aluminum metal. This can be achieved by referring to the chart for MIG welding aluminum, which offers insights into the recommended settings for MIG welding aluminum. In addition, you’ll learn about common problems and remedies for MIG-welding aluminum.

Basic characteristics of aluminum

Aluminum is a one-of-a-kind metal, with certain specific properties. It’s lightweight, electrically conductive, anti-corrosive, and has an incredible strength-to-weight ratio. Plus, aluminum is malleable, ductile, and non-magnetic. These traits make it ideal for many industrial purposes.

Here’s a list of aluminum’s notable features:

  • Low density
  • High conductivity
  • Corrosion resistance
  • Excellent strength-to-weight ratio
  • Malleability and ductility
  • Non-magnetic properties

Additionally, aluminum forms a protective oxide layer on its surface, making it extremely resistant to rust and other oxidation. Because of these distinct characteristics, aluminum is used in the aerospace industry, automotive sector, construction industry, and more.

In fact, aluminum was once considered more valuable than gold and silver. According to the United States Geological Survey (USGS), that’s the truth!

To get your welds perfect, here’s a pro tip: use these MIG welding settings when working with aluminum. Nobody likes a wobbly weld – except maybe Picasso!

Recommended settings for MIG welding aluminum

MIG welding aluminum? Get the optimal performance with the right settings! Use the appropriate table for reference. Tables should include columns such as wire diameter, shielding gas, voltage, and wire speed. Don’t forget to account for material thickness too! Thicker aluminum requires more heat input than thin materials. Plus, the gun angle can affect penetration and weld quality.

Remember: improper MIG welding of aluminum can lead to cracks and other defects (source: ESAB Welding and Cutting). So, make sure to follow the recommended settings to get a high-quality weld.

Common problems and remedies for MIG-welding aluminum

MIG welding aluminum can lead to issues, but there are solutions. Clean the aluminum surface with solvents, wire brush or sandpaper. Reduce heat if experiencing burn-through, especially in thin sheets. Aluminum has a high affinity with gas hydrates or moisture, so preheat and protect with gas.

It is important to have knowledge of MIG welding, as improper welding can cause damage. Now you can pretend to know what you’re doing with a chart to look at!


Our exploration of MIG welding aluminum is almost over. It’s key to consider how hard it can be. Low melting point makes it more precise than steel welding. But, with patience, care and commitment anyone can be an expert!

  1. Get your equipment ready. Pick the right wire diameter and gas shielding for your job. Cleaning is very important. Contaminants like oil or oxide films can ruin your work!
  2. Use the right techniques. Adjust voltage settings, use suitable wire speed, and keep a steady hand. If not, you could get uneven beads or porousness.

Remember that aluminum has higher thermal conductivity than steel. Preheating isn’t always needed. But, if the metal gauge is more than 1/8 inch, it’s a good idea.

Mastering aluminum welding takes time and effort. But, it’s worth it in the end!

Frequently Asked Questions

What is MIG welding?

MIG welding, also known as Gas Metal Arc Welding (GMAW), is a welding process that uses a wire electrode and shielding gas to join two metals.

Can MIG welding be used for aluminum?

Yes, MIG welding can be used for aluminum. However, it requires a specific wire and shielding gas that is designed for aluminum welding.

What type of wire should I use for MIG welding aluminum?

It is recommended to use a 5356 aluminum alloy wire for MIG welding aluminum.

What type of shielding gas should I use for MIG welding aluminum?

For MIG welding aluminum, a 100% argon shielding gas should be used.

What is the appropriate voltage and wire feed speed for MIG welding aluminum?

The appropriate voltage range is between 18-22 volts and the wire feed speed should be between 275-350 inches per minute.

How thick of aluminum can MIG welding be used on?

MIG welding can be used on aluminum thicknesses ranging from 14 gauge to 1/4 inch.

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Paul Dixon is a certified welder with a wealth of experience in welding and related technologies. He started his career as an apprenticeship in welding, where he learned the ropes and acquired extensive skills in the craft.

Over the years, Paul has continued to sharpen his expertise, earning him top-rated welding certification. He remains one of the most outstanding welders in the industry.

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