How To Setting Your MIG Welder for Car Panels

The most commonly used equipment for fixing car panels is MIG welding machines. Nevertheless, achieving the appropriate settings for the MIG welder is crucial for a prosperous weld.

When it comes to choosing filler metal, the ER4xxx and ER5xxx electrodes are the best options for welding car body panels. Additionally, the chemical properties of the aluminum used in the panels necessitate high voltage and wire feed speed settings to match the appropriate metal transfer mode.

We have provided some instructions below to help you set up your MIG welder for aluminum, which is considered one of the more difficult metals to weld on car panels.

Setting up Your MIG Welder for Car Panels

When it comes to repairing car panels, there is no welding machine better than a MIG welder. This type of welder is versatile and can be used with various metals, as well as handle a wider range of thicknesses compared to TIG and Stick Welding.

If you are new to using a MIG welder on car body parts, it is important to learn how to adjust the settings properly to prevent welding defects like spatter or porosity.

Refer to the Auto Body Repair Manual

To begin, it is important to identify the type of aluminum alloy used in the car panel you are working on. This will help you determine the most suitable electrode to use for your specific situation.

An excellent way to find out which specific alloy you have is to look at the body repair manual.

Choosing the Optimal MIG Wire for Auto Body Repairs

Matching the wire type to the base metal is crucial in MIG welding. Therefore, when welding an aluminum base metal, it is essential to use an aluminum wire.

It is important to note that not all wires are created equal, as different electrode types are intended for specific conditions. For instance, if you are working with a metal that is dirty or dusty, it is advisable to use a wire that contains more oxidizers.

Below are some of the frequently used MIG wires for auto body repairs:

• ER4043: preferred by most welders because it is known for flowing better; also has a lower melting point and is not super sensitive to weld cracking
• ER5356: the most commonly used aluminum filler alloy due to its high strength. It is also easier to feed through the machine.

You also can’t go wrong with ER5183 aluminum filler alloys. This wire type is compatible with a wide range of aluminum alloys. In general, the suitable filler metals for aluminum welding will fall within the 4000 and 5000 series.

It is recommended to refer to the manufacturer’s guidelines if you are unsure about the properties of a specific wire.

Choose a MIG Wire Size Suitable for Car Panels
The three most common wire sizes in MIG welding are 0.035″, 0.030″, and 0.023″. Of these, the smaller diameter wire has been accepted to be the most suitable for auto body collision repair.
So, to recap as far as wires and fillers go for car panels:
You will likely be using a wire electrode in the ER4xxx or ER5xxx series.
A smaller diameter wire has the most suitable diameter for auto bodywork.
A popular aluminum filler metal that can work with a wide range of aluminum alloys is the ER5356, which can be found in the 0.030″ size here.

Select the Shielding Gas
Typically, MIG welding is most effective when using a shielding gas composed of 75% Argon and 25% Carbon Dioxide. This blend is known to generate minimal spatter, produce high-quality weld beads, and reduce burn-through on thin metals, which is especially crucial when working with car panels.

For Aluminum welding, it is recommended to use 100% Argon shielding gas. Since Aluminum is a non-ferrous metal, it necessitates a chemically-inert shielding gas mixture.

As far as flow rate goes, you should be within the range of 20-30 CFS (cubic feet per second) for welding car panels.

Set the Voltage for MIG Welding Car Panels

Due to its thermal conductivity, which is five times higher than that of carbon steel, Aluminum retains more heat. Consequently, a low energy mode of metal transfer, such as short-circuiting, is not suitable for Aluminum. The base material will not melt adequately to achieve complete fusion.

Examples of high-energy modes of transfer include axial spray and pulsed metal spray:

• Axial Spray: A metal transfer method that employs high voltage and involves depositing wire electrodes as a stream of tiny molten droplets is known as spray transfer. This technique can release several hundred droplets per second due to its high speed. It is most effective when performed in either flat or horizontal positions.
• Pulsed Metal Spray: Pulsed spray is a variation of the spray process where the power source can alter the voltage up to 400 times per second. This technique is advantageous as it helps to maintain the weld puddle and prevent burn-through. However, it is not as widely used as axial spray due to the learning curve involved.

One of the benefits of welding aluminum is that the voltage settings remain consistent, regardless of the welding position.

To achieve axial spray transfer, a voltage range of 21-23 volts is usually required. It is recommended to experiment with the voltage on a test piece before proceeding to the actual welding. This will enable you to identify the optimal voltage setting.

Wire Feed Speed

The wire feed speed is another knob on your MIG welder that requires some experimentation with the settings using a test piece. When welding aluminum car panels, it may be necessary to increase the wire feed speed, especially when welding out of position.

Begin with some practice

As mentioned earlier, it is highly recommended to conduct some practice runs with your MIG welder before proceeding with the actual welding.

Find a scrap piece of metal to test the performance of your welder while adjusting the settings. Observe the quality of the weld and take note of the corresponding settings.

If the results are not satisfactory, make a note of your observations for troubleshooting later. Experienced operators will tell you that no two welding machines are the same.

Preparing car panels for welding:
When working with aluminum, it is crucial to clean the base metal, especially when dealing with car panels. The surface that you plan to weld is likely to have accumulated a significant amount of dirt, oil, and grime.

• Cleaning the surface of the aluminum is essential, and you can use a solvent like acetone or a potent soap for this purpose. It is crucial to note that even water vapor on the metal’s surface can disrupt the welding process.

• Use a stainless steel wire brush that you have dedicated exclusively for use with aluminum.
• Keep the aluminum covered overnight throughout the project.
• Make sure that the car panel is kept dry and at room temperature.

To summarize, the following are the recommended settings for MIG welding when working with car panels:

 

• Electrode Wire Choice: ER5356 is usually the most popular choice in the ER4xxx or 5xxx series.
• Wire Diameter: Aim for a smaller size, preferably within the range of 0.023″ to 0.035″.
• Shielding Gas: It is recommended to use 100% argon gas for welding aluminum, as chemically-inert gases are always preferred for non-ferrous metals.
• Mode of Transfer: The Axial Spray or Pulse Metal Spray mode is generally the most suitable option to use.
• Voltage: Keep the voltage at around 21-23 volts.
• Wire Feed Speed: Maintain a high level; some trial and error may be necessary to determine the optimal setting.

Recommended MIG Welder models: