Can You MIG Weld Shipping Containers?

MIG (Metal Inert Gas) welding, also known as GMAW (Gas Metal Arc Welding), is a popular welding method for shipping containers due to its high-quality welds and ease of use. However, it does require a shielding gas to protect the weld from atmospheric contamination, which can be challenging in outdoor environments.

Preparing the Surface for MIG Welding Shipping Containers

Before you can start MIG welding a shipping container, it’s crucial to properly prepare the surface. This involves removing any dirt, rust, or paint from the area you plan to weld. Here are the steps to follow:

  1. Wire Brushing: Use a wire brush to remove any loose debris, rust, or paint from the surface. This will help ensure a clean, smooth surface for the weld.

  2. Flap Wheel: If the surface is heavily coated with paint or rust, you can use a flap wheel attached to a grinder to remove the material more effectively.

  3. Pressure Washing: For stubborn dirt and grime, a pressure washer can be an effective tool to clean the surface. Make sure to let the surface dry completely before welding.

  4. Sandblasting: If the shipping container is heavily rusted, sandblasting may be necessary to remove all the rust and prepare the surface for welding. This is a more intensive process, but it can ensure a clean, uniform surface.

Choosing the Right MIG Welding Equipment

can you mig weld shipping containersImage source: Mig weld example

When MIG welding shipping containers, it’s essential to select the appropriate equipment for the job. Here are the key considerations:

Wire Diameter

The recommended wire diameter for welding shipping containers is between 0.030″ to 0.035″. This size provides a good balance between penetration and control.

Voltage and Amperage

The ideal voltage range for MIG welding shipping containers is 18V to 25V, with an amperage range of 100A to 250A. This will ensure a stable, high-quality weld.

Shielding Gas

The most common shielding gas mixture for MIG welding shipping containers is 75% Argon and 25% CO2. Alternatively, you can use 100% CO2, which is a more cost-effective option.

Travel Speed

The recommended travel speed for MIG welding shipping containers is between 20-40 inches per minute (IPM). This will help ensure proper penetration and a consistent weld bead.

Flux-Cored Arc Welding (FCAW) as an Alternative

Flux-cored arc welding (FCAW) is another welding method that can be used for shipping containers, especially in outdoor environments. FCAW is a self-shielded process that uses a tubular wire filled with flux, which produces a gas shield around the weld.

The advantages of FCAW for welding shipping containers include:

  1. No Shielding Gas Required: FCAW does not require a separate shielding gas, making it more suitable for outdoor welding where gas supply can be challenging.
  2. Easier to Use: FCAW is generally easier to set up and use compared to MIG welding, especially for beginners.
  3. Faster Welding Speeds: FCAW can typically be performed at higher welding speeds than MIG welding.

However, FCAW can produce more spatter and may not have the same aesthetic appeal as MIG welding. It’s important to consider the trade-offs and choose the welding method that best suits your needs and skill level.


In summary, MIG welding is a viable option for welding shipping containers, but it requires proper surface preparation and the right equipment. Flux-cored arc welding (FCAW) is an alternative that can be used in outdoor environments without the need for shielding gas. Regardless of the welding method, it’s essential to choose the appropriate wire, voltage, amperage, and travel speed to ensure a successful and high-quality weld.

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