Can You Weld Aluminum With a Mig Welder?

Yes, you can weld aluminum with a MIG welder using the appropriate settings and wire. Welding aluminum with a MIG welder requires specialized equipment and techniques due to aluminum's unique properties.

Aluminum has a lower melting point than steel, so it requires a different welding approach to ensure a strong and clean weld. By adjusting the MIG welder settings and using aluminum-specific wire, you can successfully weld aluminum with a MIG welder.

With the right skills and knowledge, you can achieve high-quality aluminum welds using a MIG welder, making it a versatile tool for various welding projects involving aluminum materials.

Properties Of Aluminium for MIG Welding

Aluminum is a popular material for MIG (metal inert gas) welding due to its lightweight, high strength, and corrosion resistance. However, welding aluminum presents some unique challenges compared to welding steel. With a low melting point and high thermal conductivity, it requires special welding techniques for successful fabrication.

Welding Techniques Used Specifically for Aluminum

When it comes to welding aluminum, it's important to use the right technique to ensure a strong and durable bond. This metal requires a different approach compared to welding steel or other materials. The following are the main welding techniques used for aluminum:

• Gas Metal Arc Welding (GMAW/MIG): Also known as MIG welding, this technique uses a wire electrode and a shielding gas to protect the weld from atmospheric contamination.

• Tungsten Inert Gas Welding (TIG): TIG welding is commonly used for aluminum due to its ability to produce high-quality, clean welds. It uses a non-consumable tungsten electrode and a separate filler material.

• Resistance Spot Welding: This method is often used for joining thin aluminum sheets by applying pressure and electrical current to create a weld.

Each of these techniques has its advantages and limitations, so choosing the right method depends on the specific requirements of the project.

Safety Equipment for MIG Welding Aluminum

Wearing a welding helmet during MIG is necessary to shield your face and eyes from radiation, just like it is during any other arc welding procedure. To protect yourself from radiation, extreme heat, and molten spatter, you should wear welding gloves, a welding jacket, and an apron at the very least.

It's also a good idea to wear a welding respirator, particularly if you're welding in poorly ventilated areas.

Wear safety glasses underneath the welding helmet at all times, especially during cutting or grinding. Always follow local laws and the code of conduct. Recall that while welding is a great pastime, doing it unprotected can be harmful.

Preparing Your Equipment to MIG Weld Aluminum

Let's look at all the information a novice needs to know to effectively weld aluminum. We will cover important topics such as the MIG aluminum filler wire, wire feed, spray transfer, welding machine, spool gun, and shielding gas.

Shielding Gas

When MIG welding aluminum, you typically use 100% argon shielding gas. While other gas mixtures won't aid hobbyist welders, you should be aware that helium can help you achieve deeper penetration on really thick metal pieces.

Pure argon promotes excellent arc initiation and stability, it is the most often used shielding gas. Helium adds penetration even though it loses arc stability. Moreover, the weld bead is widened. Thus, the majority of the time, pure argon shielding gas is the best option.

MIG Welding Aluminum Wire Selection

The selection of aluminum welding filler wire is contingent upon the basic aluminum alloy and the environmental factors that the final product will encounter. It is crucial to match these two factors with the filler wire.

The most commonly used MIG aluminum welding wires are ER4043 and ER5356.

A versatile MIG welding wire called ER4043 is used to join aluminum alloys 2014, 3003, 3004, 4043, 5052, 6061, 6062, and 6063. The welds have exceptional crack resistance and ductility. Additionally, adding silicon to the wire lowers the melting temperature and increases the weld pool's fluidity.

Although the ER5356 includes magnesium additions for increased tensile strength, it is less resistant to cracking during welding than the ER4043. The ER5356 welds together aluminum alloys 5050, 5052, 5056, 5083, 5086, 5154, 5356, 5454, and 5456.

Spool Gun or Graphite Liner for a MIG Gun

If you use a gra04phene liner for your MIG gun, along with a few additional elements that the manufacturer of your MIG welder may prescribe, you can effectively MIG weld aluminum without a spool gun.

Another alternative is a spool gun, but that will cost extra money. The MIG gun's spool system and wire feed drive roll are linked to the spool gun. In order to avoid wire nesting and the need for the aluminum wire to go from the wire spool inside the welder, the increased dependability of a spool gun is its benefit. However, the enormous spool linked to it makes it difficult to enter narrow locations, and it also comes with greater expenses.

Certain welders, such as the Dual Voltage Weldpro 155 Amp Inverter MIG Arc Welder, are compatible with spool guns. For aluminum MIG welding enthusiasts, a U-type roller, A+ tips, and a graphene liner combined with 100% argon shielding gas can yield satisfactory results.

Only a spool gun or a graphene liner setup can MIG weld aluminum. This is due to the soft nature of aluminum wire, which makes it prone to kinking in the standard wire feed designed for mild steel wire.

Achieving a Spray Transfer When MIG Welding Aluminum

You may transfer metal with MIG welding in three different ways: globular, short circuit, or spray. Spray transfer, however, yields the greatest results when MIG welding aluminum.

Spray transfer is a high-speed technique that transfers small molten droplets across an arc using high amperage and voltage settings. Compared to a globular or short circuit, it retains ignition, a high metal deposition rate, and a higher wire usage efficiency.

To achieve spray transfer during MIG welding aluminum, coordinate voltage and wire feed speed. Adjust the settings according to your preferences. To avoid arcing the gun tip, beginners should gradually increase wire speed and voltage. If aluminum is burning through due to excessive heat, test lower voltages first. Once proficient, test welds will be unnecessary. Use the suggested settings for the MIG welder and adjust accordingly.

Cleaning the aluminum before MIG welding

Before welding, the aluminum's surface has to have its naturally existing oxide layer removed. However, it's not a good idea to remove this layer beforehand.

It is first necessary to clean the aluminum component of any dirt, grease, or oil. If not, when you begin removing the aluminum oxide, you run the danger of encrusting these contaminants into the aluminum part.

Aluminum is non-magnetic, making it difficult for ophthalmologists to treat it if dust or debris gets inside the eyes. Wearing safety gear, especially eye protection, is essential. A stainless steel brush is commonly used for cleaning aluminum, but a wire brush made specifically for aluminum is recommended. Aluminum-specific grinding wheels can help remove surface oxide, but standard ones are not recommended due to their low melting point. Strong acids or alkalis can be used, but it must be completely dried and washed before welding.

MIG Welding Aluminum Technique

Use the push welding method, which involves moving the gun away from the puddle for improved cleaning, shielding gas coverage, and less weld bead contamination, to produce the best possible weld quality while MIG welding aluminum. The limited temperature window between strong heat conductivity and the low melting temperature of aluminum necessitates substantial heat input, which calls for hot and rapid welding. In order to prevent burn-through and to accelerate the travel speed as the metal component warms up, a high travel speed is required.

If you need to weld slower, you can use a heat sink to absorb the excessive heat conducted away from the welding joint.

When MIG welding aluminum with a spray transfer, it is imperative to have a longer wire stick out, approximately 3/4" between the wire tip and the metal piece, in order to achieve a continuous spray transfer. Shorter stick-out distances may make it harder to maintain a constant transfer, resulting in burns. In addition, wire burning back to the contact tip can be avoided by having it recessed by about 1/8" inside the nozzle.

It is beneficial to move the part to disperse heat and minimize deformation of the thin metal bits that are melting through. Therefore, splitting welds into several phases is advantageous, if at all feasible.

Avoid Pre-heating of Aluminum in Mig Welding

In most cases, preheating the aluminum in a professional environment is not required. Nevertheless, if you're MIG welding aluminum for a light shop or hobby use, preheating is advantageous. To weld thicker material and large aluminum parts, preheat the material using a conventional rosebud to roughly 200°F.

Aluminum has a strong conductivity, which makes it occasionally challenging to weld thicker pieces with conventional equipment. Professionals can use pricey, high-amperage equipment to weld thicker metal without a preheat, but most individuals lack the means or demand for industrial-grade welders.

Never preheat aluminum above 200°F because excessive heat exposure causes the metal to lose its mechanical qualities. Therefore, use preheating sparingly and only when required.

Conclusion

Welding aluminum with a MIG welder is possible with the right techniques. Understanding settings and using proper equipment is key. With practice and patience, you can achieve strong and clean welds on aluminum. Keep experimenting and refining your skills for successful aluminum welding projects.