MIG Welding Basics and Creating Strong Welds

by Steve Darnell
MIG Welding

Hobbyists and professionals will both agree, MIG welding is one of the fastest and easiest ways to make strong welds. Learning how to MIG weld is something every welder needs to do. It’s an essential skill to have for customization and fabrication projects. It takes a mix of knowledge, practice, and the proper equipment to succeed at this skill.

To help you better understand the basics of MIG welding and how to make stronger welds, this article is a great resource to start with. Here’s what you need to know so you can begin building your welding skills!

What is MIG Welding?

MIG stands for “metal inert gas” and is a welding process that uses a MIG welding machine and shielding gas. This welding operation is one of the most commonly used techniques. 

You can use this method to repair your child’s bike, work on your project car, or complete major fabrication projects and builds. You’ll find MIG welding equipment in metal shops, auto garages, construction sites, among many other job sites. MIG welding is quick, inexpensive, and it’s easy to train people how to do it safely.

There are two types of MIG welding. The most common uses a gas shield which this article will cover. The other type uses flux core welding wire. You can learn more about that operation by clicking here.

While it might require more of an investment upfront to purchase gas supply and bottle, gas shield welding creates stronger welds and avoids the splatter mess that flux core welding creates. This MIG welding method feeds a solid wire electrode and shielding gas through the welding gun to make the weld. 

The wire is used to melt and join the two pieces of metal together. Like other welding operations, this method can use different thicknesses of wire ranging from 24-gauge up to ½ inch thick.

The gas is used as a shield to protect contaminates from causing the weld to fail. Contaminants can be created when the extreme amounts of heat produced by the arc lead to a breakdown of chemicals in the air which then form smaller molecules. 

MIG Welding Safety Tips

It doesn’t matter if you’re a working professional or a weekend warrior, safety should come first with any welding operation. Investing some money into proper safety equipment will cost less than a trip to the emergency room and will help keep you protected from even minor emergencies. 

There is no sense in putting yourself at risk for injury when you can actively take steps to prevent them!

Personal Protective Equipment

Don’t forget to put on the proper clothing and safety equipment, like personal protective equipment (or PPE). It might be hot outside, but it’s not nearly as bad as the feeling of splatter burning your arms, hands, or face. 

Make sure to wear long sleeves and a welding apron or a welding jacket. You should also be wearing steel-toe work boots, thick pants, gloves, and a welding helmet. If anyone is around and watching you work, they need a mask as well.

The light created by the MIG welding operation can lead to permanent eye damage, migraines, and other severe injuries if you aren’t wearing the proper eye protection.

Work Area Preparation

You also need to make sure your work area is safe before you start working. First, make sure that you’re not working next to any chemicals or flammable liquids or objects like an old oily rag. One errant spark could lead to a fire and a much bigger problem. Speaking of fires, make sure that your outlets and wiring can handle the job. Welding machines draw a lot of power and can cause electrical fires if the wire gets too hot before tripping the circuit breaker. 

If you plan to use anything with more output than 110 volts, you may want to have an electrician check things out first. Another option to consider is having a dedicated outlet installed for your welder to avoid causing damage to your fuse panel and existing wiring.

Make sure you have proper ventilation as well. MIG welding can create nasty fumes that present serious health risks. You need airflow, just make sure that the airflow is not disrupting the output of your shielding gas.

The final thing to do when preparing your work area is to check your equipment. Make sure that no leaks are coming from the gas regulator, valves, or hose before beginning your welding operations.

Selecting the Right Gas and Wire

To get the best results and ensure your making the strongest welds possible, it’s essential to select the correct wire and gas. Depending on the type of metal you are welding, you’ll need to adjust the mix of gas and the type of wire you use. 

For any projects that involve carbon steel, you’ll need to run a 75/25 mix. This combination of gas is a mix of 75% Argon and 25% CO2. As for the type of wire, make sure to use steel.

If you want to get the best results possible welding stainless steel, you’ll need tri-mix gas. This combination of gas includes Argon, CO2, and Helium. You’ll want to make sure you switch out the wire in your machine and use stainless steel wire.

Last but not least, let’s cover aluminum MIG welding. With this type of material, make sure that your gas is 100% Argon. You’ll need to use aluminum wire in your machine. One important thing to note here is that aluminum wire is quite fine. If you use the same welding gun as the above materials, you run the chance of the wire getting damaged or stuck as the machine feeds it. To avoid this from happening, use a spool gun instead.

How to Make Stronger MIG Welds

If you want to improve your MIG welding skills and make stronger and more durable welds, there are three main areas to focus on—material preparation, machine setup, and operator technique.

Prepping Your Materials:

Solid MIG wire has trouble performing well when rust, dirt, oil, or other contaminants are present. Unlike flux-cored wire, MIG wire requires clean metal to make quality welds. Before you start any MIG welding operations, you’ll need to spend some time with a wire brush or grinder. Make sure to remove any of the above contaminants, so you’re working with bare metal. For best results, use a grinder equipped with a wire disc wheel.

Another piece of advice here, make sure your clamp connects to clean metal as well. If there’s any electrical disruption, it will affect the wire feed.

MIG Welding Machine Setup

Making sure your machine is set up correctly for the type of metal your welding is very important. If you don’t get this right, the results will speak for themselves. To avoid this from happening, keep these four things in mind when setting up your machine.

Wire Selection and Size

As mentioned earlier, the type of wire you select is very important. You’ll also want to consider the size of the wire you use. For most general applications, a wire with a 0.030 inch diameter should get the job done. 

If you’re welding a thicker piece of metal stick to 0.035 inch or up to 0.045 if your machine can handle it. If you welding something thinner and want to reduce the heat input, use 0.023 inch wire.

Gas Selection

For most general welding operations, a 75/25 mix of Argon and CO2 will do the job. However, make sure to adjust the gas as mentioned earlier if you’re welding stainless steel or aluminum. 

You’ll also want to pay attention to how much gas is flowing from your bottle. When you adjust your regulator, keep the flow around 20-25 cubic feet per hour.

Machine Voltage

Depending on the thickness of materials, type of materials, wire diameter, shielding gas mix, and joint configuration, you’ll need to adjust your machine’s voltage and amperage. 

Most machines will include a reference chart on the machine or you can quickly look it up online. Some machines have auto-set features to automatically adjust by selecting the diameter of the wire you are going to use.

Wire Stick Out

The last variable for machine setup is your wire stick out. This is how much of the wire is sticking out from your gun. You’ll want to keep this short. Try not to have more than ⅜ of an inch sticking out from the gun. Too much wire sticking out is one of the most common errors made by new MIG welders.

MIG Welding Technique

Last but not least, you will want to focus on your technique when it comes to making stronger MIG welds. The first thing to consider is if you’re pushing the gun towards the weld pool or pulling it away. Both options will work, but the pushing method offers a better view of what you’re doing and makes it easier to direct the wire into the weld joint.

The next thing to consider is the travel angle of the welding gun. In most cases, you’ll want to keep this around 5 to 15 degrees. If the angle increases and gets beyond 20 to 25 degrees, you’ll end up with more splatter and less penetration on your materials.

The final part to consider is your travel speed. This is how fast you complete your weld bead. If you’re moving the gun too slowly across the joint, you’ll hear more of a steady noise than the rhythmic crackle you should. You’ll also notice a lot of discoloration on the area around the weld. A travel speed that is too fast can cause the bead to be thinner and prevent it from properly penetrating the joint. 

To get the ideal travel speed, listen to the crackle. It should be rhythmic and almost sound like the sizzle of bacon cooking in a frying pan.

Good vs. Bad MIG Welds

There are a lot of variables that go into making a good or bad MIG weld. Everything from the machine setup and prep work to the technique and travel speed can impact the quality of your weld.

It is important to understand the difference between a good and a bad weld so here are a few characteristics that will help you determine the quality of your MIG weld:

Good MIG welds have…

  • A minimal amount of splatter and sparks
  • A rhythmic crackle sound
  • Clean appearance showing minimal to no contamination
  • Minimal discoloration to the work material
  • Weld resembles a stack of dimes

If your welds don’t look and sound like this, there could be a few reasons why.

Bad MIG welds are caused by…

  • Wire being fed too slow or too fast (listen for a very fast or very slow crackling sound)
  • Operator’s travel speed (keep your pace steady)
  • Incorrect stick distance (adjust how much wire is exposed from the gun)
  • Not enough shielding gas used (increase gas flow to protect the weld from contaminants)

Learn the Secrets to Making Great MIG Welds

Now you can see why MIG welding is one of the most popular and useful welding skills to have. If you want to learn even more about developing this skill, enroll in Welder 101 today! 

Every new welder has a lot of questions when first starting out. This comprehensive course combines over 30 plus years of welding experience into a straightforward and easy-to-understand welding masterclass.

Enrollment comes with lifetime access to over 50 video tutorials as well as access to all future training materials. You also get to learn from your peers and mentors by accessing our private Facebook group. Inside this community, you can ask questions and get feedback from other students and the Welder 101 team.

Besides just the knowledge and skills you’ll develop, you’ll also receive discounts on WelderUp merchandise and equipment from some of the industry’s most reputable suppliers. 

Click here to learn about the Welder 101 course and get enrolled today!

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