MIG welding (or GMAW - gas metal arc welding) is probably the easiest to master out of all welding methods that exist. Unlike TIG where both hands are involved in the welding process, MIG requires the use of only one hand to hold the MIG gun. However, laying a quality seam with a MIG welder not only requires a certain set of skills. Welders also need to adjust their machine settings for each individual project. In this blog, we will cover what a MIG welder is, provide tips for optimal MIG welder set up, explain why MIG welders are better than other machines as well as answer some of the most common questions about MIG welding.

 

Before we get into more details, it is crucial to understand that there is no perfect MIG welder set up. However, there are general guidelines, which will help you achieve a good quality weld. 

 

1. What is MIG welding?

MIG is an arc welding process. The critical role in MIG welding is allocated to a MIG welding gun through which a continuous solid wire electrode is fed and upon melting dispersed into the weld pool, fusing the two pieces of metals together. The weld pool is protected by the shielding gas also dispersed through the welding gun. 

 

MIG welding is great for beginners as it is relatively easy to master. It is one of the most used methods for DIY projects, light fabrication and repairs on materials thicker than 24 gauge up to ½ inch. 

 

2. How to set up your MIG welder for the first time?

Every welding machine is different and needs to be re-configured for every different project. However, the general guidelines say that the selection of gas, electrode, wire speed and travel speed as well as power settings for MIG welding depend on the type of metal, metal thickness and the welding techniques used. It is also important to read the user’s manual to better understand the capabilities and limitations of your specific welder.

 

3. Three crucial settings of a MIG welder

Voltage, wire feed speed and gas flow rate are the three basic settings of a MIG welder. They are also the ones that play a crucial role in laying good quality welds. 

 

How to adjust a MIG welder voltage settings?

The voltage you set determines how deep the torch penetrates the metal. Too high voltage settings lead to poor arc control which further leads to the inconsistent weld pool and penetration of the base metal. Too little voltage leads to difficulties in starting and controlling the arc. Thus, it is crucial to set the correct voltage rating before starting to weld. For instance, Lincoln Power MIG 256 has a voltage control knob that allows you to set the desired voltage. 

 

If you are a beginner using the machine for the first time, it is recommended to set the medium voltage to fit the variety of welding projects. You will learn how to use your MIG welding machine as well as learn its minimum and maximum voltage settings with time. 

 

How to adjust a MIG welder wire feed settings?

Wire feed settings are the speed with which wire electrodes are fed into the weld pool and are measured in inches per minute (IPM). 

 

If the wire is fed too fast, it can create a burn-through. A wire that’s fed too slowly results in the wire burning slowly, producing an unstable arc. Refer to the MIG welder settings chart provided by the American Welding Society for optimal wire feed speed settings. 

 

How to adjust a MIG welder gas flow rate settings?

Determining the correct gas settings for MIG welding is as important as setting the right wire feed speed. A correctly configured gas flow rate will help control the transfer of gas over the weld pool to protect it from air contamination. It is measured in cubic feet per minute (CFM). If the gas flow rate is too low, the weld seam may end up being porous. If too much gas is dispersed, it will result in a turbulent arc and a contaminated weld. Try different gas flow rates to determine the most optimal one before starting to work on your actual project. 

 

FAQs:

 

1. What causes spatter in MIG welding?

Incorrect MIG welder settings are one of the most common reasons for excessive spatter produced during MIG welding. You risk producing excessive spatter if the following settings are incorrect:

Current or voltage. These settings are important for achieving proper heat and metal penetration. If set incorrectly, you risk the base metal being burnt through or the weld bead being too thin for the thickness of the base metal. Click here to learn more about how different current outputs can affect weld quality.

 

• Wire feed speed. Too slow a wire feed speed can result in the wire melting too far away from the base metal. Too fast a wire feed speed also produces excessive spatter. 
• Gas flow rate. Setting an incorrect gas flow rate can result in air contaminants affecting the weld. 
• The wrong gas type is used. Using the wrong gas type can result in poor-quality welds and excess spatter. 
• The wrong polarity is used. Forgetting to switch polarity for solid wire is also a common cause of excessive spatter. 

 

2. What are the four MIG welder filler metal transfer types?

In MIG welding, the following are the four methods the filler metal is transferred to the weld pool:

 

• Short circuit
• Globular
• Spray
• Pulsed spray

 

Short circuit. In this method, the short circuit is created when the wire contacts the base metal. The wire instantly heats up and melts into the weld pool. This process keeps repeating over and over again many times per second. During the transfer method, the short circuit produces a very distinct crackling sound. The short circuit transfer method is mostly used on thin metals and sheet metals. It also creates a considerable amount of spatter.

 

Globular. A globular method is very similar to the short circuit - the filler electrode touches the base metal and creates a short circuit. The difference is in the electrode melting - the electrode wire melts longer and creates a large volume of molten filler metal that drips into the weld pool. This transfer method requires high heat input and limits welding positions to horizontal and flat only. 

 

Spray. In the spray arc method, the molten wire electrode is constantly sprayed into the weld joint. This method uses a high heat input. Therefore, it presents a high risk of burn-through on thinner metals. 

 

Pulsed spray. In the pulsed spray transfer method, droplets of molten metal form at the end of the wire electrode and are then pushed across the arc into the weld pool. This method is the most preferred, but it requires a special power source where the voltage is pulsed multiple times per second. Every pulse equals a new droplet of the wire electrode. 

 

3. What if I set the wire feed speed too high?

Setting the wire speed too high for the material can result in weld seam deformation or an unstable arc. You should test the machine before getting down to the actual job.

 

4. Is there an optimal MIG gun angle?

The majority of MIG welding is done with the MIG gun at a 90-degree angle. However, when welding in tighter spaces, the angle might need to be adjusted. 

 

5. How can I improve the quality of my weld seams?

Laying quality welds takes time and experience. While practice is the key to making perfect welds, it is also crucial to adjust your MIG welder settings. 

It takes time to become an expert in MIG welding. Not only does it involve refining manual skills, but it also requires the correct MIG welder set up. This blog prepared by Lock 8 Equipment Inc. provides preliminary guidelines on how to set up your MIG welder for the first time. However, you need to test the machine several times, preferably on the same type of material, to find the middle ground where your MIG welder performs at its best capacity.