Aluminum Welding: Practical Skills and Tips

1. Five tips for aluminum welding

1. The wire drawing welding gun is best suited for welding aluminum. If it is not possible to use this type of welding gun, try to use the shortest welding gun to maintain a straight position. Only argon should be used as a shielding gas. When welding aluminum (automatic pipe welder), only a push gun should be used.

2. If you encounter a wire feeding issue, you can try using a conductive head that is one size larger than the welding wire.

3. The most commonly used welding wire for aluminum welding is the softer standard welding wire. The other option is a harder (easier to feed) welding wire, which is mainly used for welding operations that require higher hardness and strength.

4. Before welding, the oxide layer on the aluminum surface should be removed using a special stainless steel brush.

5. Fill the crater at the end of welding to prevent cracks. One method is to keep the welding gun in the molten pool for a few seconds after welding.

2. Precautions for aluminum profile welding

1. Welding of aluminum

Welding Characteristics: Aluminum and aluminum alloys have strong thermal conductivity, high heat capacity, a large linear expansion coefficient, low melting point, and low high temperature strength, making them challenging to weld.

To ensure quality welding, certain measures should be taken.

For cleaning pipe fittings and welding wires, the surfaces within 50mm on both sides of the welding wire and break should be cleaned with acetone, and the surface oxide film should be scrubbed with a stainless steel wire to reveal the metal shine.

The cleaned break must be welded within 2 hours, and the cleaned welding wire must be placed in a unused cylinder and used up within 8 hours, otherwise it should be cleaned again.

Cerium tungsten rod should be selected as the tungsten rod, the argon purity should not be less than 99.96%, and the water content should not exceed 50mg/m.

The ambient temperature should not be lower than 5°C, otherwise it should be preheated to 100~200°C before welding, and the relative humidity should be controlled.

2. Required equipment

You need a welder with a minimum capability of $4000 and exceptional welding proficiency to effectively weld aluminum.

Practice is crucial in achieving successful welding outcomes.

It is necessary to invest in high-cost welding guns specifically designed for aluminum welding.

3. Successfully welded aluminum

The reality is that, with proper training, the use of appropriate welding equipment, and the correct setting of parameters, even a compact and small MIG welder can perform aluminum welding temporarily.

MIG welding machines can be utilized for welding various materials in a home setting, such as barbecue grills, outdoor storage sheds, docks, and decorative pieces.

However, even for home welding enthusiasts who frequently weld steel, welding aluminum can prove to be a challenging task.

This is due to the soft nature of aluminum wire, which makes it difficult to feed the wire through the welding machine.

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Moreover, the wire diameter and welding machine settings that are commonly used for steel may not be appropriate for welding aluminum.

3. To successfully weld aluminum, you need to understand the following problems

1. What kind of equipment do I need?

The first step in the process is to determine the required equipment to achieve the desired outcome.

It is important to note that a 115-volt wire feeder is capable of welding materials ranging from 22 to 12 in size, and with proper preheating, it may be possible to weld materials that are 1/8 inch thick. However, caution must be exercised as the maximum preheat temperature is limited to 250 degrees Fahrenheit.

On the other hand, a 230-volt machine is capable of welding materials ranging from size 22 to 3/16 inch, and with proper preheating, the range can be increased to 1/4 inch.

If you plan to weld plates of varying thicknesses, it is advisable to consider a 230-volt welder.

It is also worth remembering that if you plan to regularly engage in aluminum processing, you will require a heavy-duty welder.

Compact MIG welders with 115 and 230 volts can be used for occasional aluminum welding, but they are not suitable for complex and heavy aluminum welding projects. In such cases, it is advisable to opt for welding equipment with an output of more than 200 amps.

Once the input voltage has been determined, another common question to consider when selecting a welding machine is whether to choose a continuous voltage regulation model or a tapped coil model.

The continuous voltage regulation model provides the ability to adjust the set voltage seamlessly within the machine’s voltage limit, resulting in greater adaptability, more effective adjustment, and precise control.

This makes it easier to make adjustments during the welding process.

2. What kind of shielding gas?

The shielding gas required for MIG welding aluminum and steel is distinct.

When welding aluminum, it is recommended to use 100% argon as the shielding gas. On the other hand, steel welding requires either a mixed gas or 100% carbon dioxide.

The good news is that there is no need for any special equipment, as your existing regulator (excluding a carbon dioxide regulator) and gas piping can be used for either pure or mixed gas.

3. What polarity is set?

All MIG welding, including aluminum welding, requires the use of a positive electrode, while the flux-cored welding process typically uses a negative electrode.

If you plan to switch between welding processes using the same machine, it is important to first determine the required electrode polarity. This is a common mistake among novice welders.

4. What kind of aluminum alloy electrode should be purchased?

If you attempt to use steel electrodes when welding aluminum, the results will be unsatisfactory.

Instead, it is recommended to use a 4043 aluminum alloy filler metal with a limited diameter of 0.035 inches for compact MIG welding.

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While 5336 aluminum alloy electrode may be more readily available and easier to feed wire due to its hardness, it is not necessarily the best option for obtaining good welding results.

Although 4043 aluminum alloy is soft, it can still produce good wire feeding results if the appropriate steps are followed.

It is crucial to avoid using welding wires of other diameters. In particular, steer clear of 0.030 inch welding wire (as it is difficult to feed) and 3/64 inch welding wire (as a compact and small welding machine may not provide enough current to reliably melt the welding wire of this diameter).

5. How can I set up my welder to weld aluminum?

Now that you have a better understanding of the types and capabilities/limitations of welding machines, the next crucial step is to learn how to set the parameters correctly.

Here are some tips to follow: invest in a set of aluminum wire feeding tools.

It is important to keep in mind that wire feeding is even more crucial when welding aluminum, and it is highly recommended to purchase a set of specialized aluminum wire feeding tools, which will typically include the following items:

Non metallic liner – designed to minimize feed

A Wire friction 2 U-groove driving roller – used to prevent the breaking or deformation of soft aluminum wire. These drive rollers will not cause scratches on the aluminum wire, unlike V-groove rollers.

If V-groove rollers are used, the welding wire can scratch the liner, causing blockages and resulting in wire feeding failure.

Inlet and outlet guides – designed to prevent wire scratches.

Contact – the contact head used in aluminum welding has a larger diameter opening as aluminum wire expands more when heated compared to steel. The special contact head for aluminum wire is designed to be small enough to maintain electrical contact while allowing for this expansion.

Load welding wire to welding machine

Here is a trick to correctly load aluminum wire (which is also applicable to steel welding wire). Proper loading is crucial to prevent welding failure.

Use one hand to securely hold the welding wire spool to prevent it from becoming loose.

Once you have removed the cellophane packaging, hold the loose end of the welding wire with your other hand and do not let go until you have placed it in the drive roller.

Novice welders often make the mistake of not holding the loose end, causing the entire bundle of welding wires to loosen and scatter.

If this occurs, there is no solution and the welding process will be significantly impacted, requiring you to purchase a new bundle of welding wire.

Set the tightness of welding wire brake

The tightness needs to be sufficient to prevent the welding wire from becoming loose, but not so tight that it drags the welding wire.

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To set it correctly, first adjust the tightness to the minimum and then install the welding wire, allowing it to pass through the drive roller.

If the welding wire roller is moving while the other parts remain stationary, it means the tightness is not enough.

It is crucial to exercise caution when operating, as excessive tightness can put excessive force on the welding wire.

Additionally, do not panic when the last few rounds of welding wire cannot be fed, as this is often due to the welding wire being too stiff to easily loosen.

Set the tightness of the drive roller

This step is considered to be one of the most critical in the entire setup process.

Experts suggest positioning the wire head at a slight angle, approximately 1 inch from the surface of the insulation material.

Next, set the roller tightness to almost the minimum.

Turn on the switch on the welding torch and observe its operation – the welding wire should smoothly glide when it comes into contact with the insulation material.

From this point, adjust the tightness until the welding wire stops sliding.

It is important to note that excessive tightness can cause the welding wire to break.

This occurs when the welding wire remains in the welding gun while the drive roller continues to rotate, causing the welding wire to break after it has exited the roller or get backed up, leading to a mess of welding wires, including the guide liner, welding gun liner, etc.

Remember, when setting the roller tightness according to the instructions above, be sure to wear high-quality welding gloves as the welding wire that is emitted from the welding gun is hot.

Ensure a good power connection

First, the welding fixture must be securely clamped in an area where the welding workpiece is not contaminated or covered with paint.

To prepare the workpiece, use a degreasing solvent to remove any grease. Make sure that the surface of the workpiece is dry before starting the welding process.

Additionally, do not perform welding on containers near any flammable materials, such as solvents or paints.

Step 2: clean the oxide on the surface of aluminum with a clean stainless steel wire brush.

Positioning is very important

When welding, it is important to maintain a straight welding gun cable to minimize any hindrances in the feeding of soft aluminum wires.

Bending the torch cable can cause the welding wire to become tangled, leading to ineffective wire feeding.

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