CO2 Gas Shielded Flux Cored Wire

MIG Flux Core Wire: The Essential Guide

Whether you’re just getting into welding or if you’ve been doing it all your life, it’s never a bad idea to learn more about specific tools and equipment you’re likely to encounter. In this guide, we break down all the questions you could ever have about MIG flux core wire and what goes into it, from thickness to flux.

MIG flux core wire is an essential component of many different kinds of welding, so you’ll want to know what it is and how it works if you’re trying to get into metalworking.

What Is MIG Flux Core Wire?

MIG flux core wire has been around since the 1950s, and at this point, it has been fully integrated into the modern welding landscape.

MIG stands for metal inert gas, which refers to the mini-atmosphere generated by the flux core present in these wires or pumped externally during welding. This mini-atmosphere protects the welding process from the effects of oxidation on the weld, which can weaken the joining metal and cause it to become brittle and porous.

The resulting atmosphere can be composed of various gasses, but generally, they are non-reactive and include options like carbon dioxide, helium, argon, or some mixture of these three.

Types of MIG Flux Core Wire

There are two kinds of MIG flux core wire: gas-shielded and self-shielded. Gas-shielded flux core wire requires a tube to pump gas over the welding process continually to protect the weld from oxidation. Self-shielded flux core wire relies exclusively on the flux itself to produce the required gas.

Because self-shielded flux core wire isn’t reliant on any outside gas being pumped through the welding process, it is ideal for any welding work outside. You can use self-shielded wire for bridge-building, ship-building, auto mechanics, and scrap metal art.

That said, on excessively windy days, you probably won’t want to get into any kind of welding, as strong winds and various forms of precipitation can interfere with even the most resilient welding atmospheres.

Grahpic of MIG welding tool

Thicknesses of MIG Flux Core Wires

MIG flux core wire comes in a variety of thicknesses. Generally, the thicker the wire, the better at joining gaps. If you’re trying to join two pieces of metal with rough or jagged edges, you’ll likely want to use thicker MIG flux core wires, as these will more smoothly join the pieces by filling a more significant gap.

Thinner MIG welding wire usually allows for finer work, so if you’re looking for a bond that is a little bit harder to notice, you should go with a thinner option.

However, this isn’t always the case – different types of metal will call for different thicknesses, so make sure you’re paying attention to the AWS classification of whatever wire you’re considering the use of – following manufacturer recommendations is a must before you get involved in just about any type of welding – for obvious reasons.

Another thing that you’ll want to keep in mind is the presence of slag during the welding process. Most of the time, MIG flux core wire with a thicker diameter will produce more overall slag once the welding process is finished. Both gas-shielded and self-shielded wires will result in slag, so don’t think you can get out of dealing with it by switching types.

What are the downsides of slag? Well, you’ll need to clean it off the weld once everything has cooled down and solidified, either by scrubbing, chipping, or grinding it off. Avoiding this cleaning process can harm the overall integrity of your weld.

What You’ll Need to Use MIG Flux Core Wires

To use this flux core welding wire, you’ll need a welding setup, which means you’ll need safety equipment to stay safe throughout the welding process. We recommend investing in a welding helmet to protect your face and eyes from sparking on basic equipment.

These sparks can be bright enough to burn your eyes without a proper mask and hot enough to injure your skin. After all, your face will be close to what you’re welding to ensure you get a good enough view of what you’re doing.

Some other pieces of basic equipment we would recommend include thick work gloves to protect your fingers, boots, and long sleeves and pants to cover up any exposed skin.

You will also want to ensure you’re working in the proper conditions and following manufacturer instructions to the letter. That means knowing what kind of MIG flux core wire you’re working with and ensuring you’re in the proper atmosphere before getting started.

Using gas-shielded MIG wire outdoors won’t just risk your weld – it could also lead to serious injury and other issues. Make sure you know what kind of wire you’re working with and that you’re using it with the correct type of metal. Some types of wire aren’t compatible with certain types of metal.

Large roll of MIG flux core wire in workshop

Advantages of Flux Core Welding

You might wonder why people use flux core welding instead of arc welding. Well, there are a few reasons for it. First and foremost, flux core welding is generally considered the easiest kind of welding to get involved with, especially if you’re working with self-shielded MIG flux core wire because you can do it just about anywhere – including outside – and it is usually an automatic or semi-automatic welding process.

You don’t usually have to bother too much with learning to control many different pieces of equipment. While it can be a pain to deal with the scrubbing aspect when slag builds up near the end of the process, overall flux core welding is just easier.

And, while easier, it doesn’t result in a lesser-quality weld or anything. Sure, the work might not be as precise, smooth, or seamless as you could get through using another process, but it will almost always result in at least a passable weld that gets the job done.

Another great advantage of MIG flux core wires is that they are naturally more resistant to dirt, grime, and other contaminants that could interfere with welding. This is another bit that makes them very appealing to new welders. Sometimes, it can be challenging to detect the presence of dirt or particulates that have snuck into your welding process, and by the time you notice, it is too late!

Check out this informative video to learn how to get the perfect flux core weld every time.

What Else Is There to Know About MIG Flux Core Wires?

At this point, we’ve covered all the basics you would want to know about MIG flux core wires. These versatile wires are incredibly useful to new welders and the flux core welding process as a whole.

We hope that this guide was able to fill you in a bit more on how they work and why they’re so appealing. It’s important to always consult with manufacturer instructions before getting down and using them in the welding process.

Still, we’re confident you’ll be able to figure out all the different applications these wires are good for. As we mentioned, they keep grime out, can be used both inside and outside (depending on whether they’re gas-shielded or self-shielded), and will always result in a quality weld if you use them correctly. Good luck!

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