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When to Use Solid Wire MIG or Flux Cored MIG Welding

By September 19, 2016December 25th, 2020No Comments

MIG welding offers the convenience and speed of a feeder that guides the metal wire right into your puddle, but keeping your weld free from contaminants will determine the strength and appearance of your weld. While solid MIG wire requires a shielding gas to protect the weld, typically a mix of Argon and CO2, there’s also flux cored MIG wire that shields the weld on its own without the help of gas. The flux in the MIG wire melts in the weld puddle and provides all of the shielding that your weld requires, and you can chip the flux away after it hardens.


Both types of MIG welding wires offer advantages and disadvantages, and we’ll take a look at which will work the best for your welding project. Here are several scenarios to consider when choosing your MIG welding process.

One Twist with MIG Welding Wires

Before we get started with flux cored MIG wire vs. shielded solid MIG wire, you also have the option of working with gas shielded flux cored MIG wire that is typically use for vertical and uphill MIG welds. This combination provides an immediate, thin shell over the weld that holds the molten metal in place, prevents contamination, and chips off quite easily.

Overall, flux-cored wire makes it easier to weld out of position or in vertical and horizontal positions since the flux coating can help keep the weld in place as metal solidifies.

Portable Welding and Outside Welding

Since shielding gas can be difficult and dangerous to transport and windy conditions can minimize the effectiveness of shielding gas for solid cored wires, flux-cored MIG wires are ideal for portable welding operations or jobs that are outside. Since the flux shields the weld as part of the wire, the wind simply won’t be a factor. In addition, many outside welding jobs won’t call for the same level of attention to the weld’s appearance, so flux-cored should typically work just fine.

Faster Welding with MIG Machines

In some cases, welders report that flux-cored wire makes it easier to weld faster (although, remember you need to factor in clean up time!), especially if you use more of a drag angle that makes it easier to see the weld puddle while working. At the very least a flux cored wire removes the need to worry about shielding gas, which adds an element that needs your attention and adds an additional cost.

Material Thickness Concerns with MIG Welders

When you’re MIG welding on thin material, the flux cored option is not ideal. You’ll be better off using solid cored MIG wire with shielding gas that provides a cleaner, more precise weld.

When you work with a flux cored MIG wire you’re going to have a lot of spatter on the weld that will need to be cleaned up at the end, which usually isn’t recommended for thinner metals. In addition, some welders recommend only working with metal that is 20 gauge or more when welding with flux cored MIG wire.

Weld Quality with MIG Welders

Many welders opt for a MIG welder because of its convenience and accuracy when creating welds. You can work continuously to create solid, clean welds that will be neat and visually appealing—that is, if you use a solid wire with shielding gas. While flux cored wire can create a strong weld in thicker metal, you will lose some neatness in the finished weld.

Welding Dirty Metal

While it’s always ideal to clean your metal before MIG welding, sometimes a flux cored MIG wire is ideal for metal that is either dirty or poses a risk of contamination. Even with cleaning and a proper shielding gas set up, some metals may join better with flux cored wire in the mix.

For welding service in the greater Atlanta area, please contact Midsouth Mechanical