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How Many Amps Does a MIG Welder Use? Ultimate Guide

MIG welding creates strong and durable welds and is a reliable method of welding in various industries.

Behind the curtain of this welding method, the most important aspect that controls the welding process is the amperage.

As a professional welder, I have often been asked “How many amps does a MIG welder need?” Well, the answer is not a simple or straightforward one.

In this article, I will delve deep into the details of amperage secrets and their impacts on welding performance.

There are many mysteries hidden in the current control when it comes to welding and unlocking these mysteries can help you become an efficient welder.

Let’s dive into the details of amperage control in MIG welding.


Understanding Amperage in MIG Welding

Understanding the fundamentals of electric current and its flow is important to comprehend its significance in MIG welding.

Current is measured in amperes and is the flow of electric charge through a conductor. Hence, the higher amperage you have in settings, the more current is being passed through the conductor.

In the case of MIG welding, the amperage will determine the heat input and penetration. More amperage means a higher heat input which will create a greater arc for deeper penetration.

The deposition rate of the weld is also determined by amperage levels. However, you cannot just use any amperage settings for welding metals.

Each metal has its own specific amperage range for welding and there are a lot of other factors that influence the amperage settings as well.

Importance of Selecting the Right Amperage

Each MIG welder comes with a specified amperage range, denoting the minimum and maximum amperage settings that can be used on that machine.

Knowing the amperage range will specify what tasks and materials you can use this welder for and what falls out of its purview.

The range allows welders to adjust the heat output according to the requirements of the welding task at hand, leaving some room for flexibility and personal adjustments.

Understanding the amperage range is crucial because it will help you make an informed decision when it comes to selecting a specific amperage for a welding task.

Getting the amperage right is crucial to achieving optimal welding results.

Factors Influencing Amperage

Various factors play an important role in determining what amperage would be right for the specific welding task.

These factors include material thickness and type mainly, but there are also other minor factors that influence amperage as well.

Type of Metal

The very first thing that you must determine is what type of metal you are going to be welding. Each metal has its own degree of strength, melting point, and electrical and thermal conductivity which helps you determine the amperage required for its welding.

Since each metal differs from the other in its characteristics, you cannot use similar amperage settings for welding all sorts of metals.

You can get help from an online tool that would take the necessary information and calculate the exact amperage based on specific welding requirements.

Or you can use a detailed amperage chart that will help you calculate the required amperage.

Once you become a pro in MIG welding, you will have these settings on your fingertips and will be able to quickly adjust the MIG welder amperage to achieve desired results.

Thickness of Metal

Whether you are a beginner or professional, it should be obvious that welding thicker sheets of metal would require more amperage than welding thinner sheets.

Amperage is directly proportional to heat input. So, higher amperage means more heat input which is a must when welding thicker material.

However, while calculating the required amperage for a specific thickness there is no general formula. For each metal, the settings will differ.

As a general rule of thumb, you need 1 ampere of power for every 0.001 inch of steel.

However, when welding stainless steel or aluminum, these settings differ greatly. Stainless steel requires 10-15% less current for the same thickness and aluminum needs 25% more current.

Even this rule of 1 ampere per 0.001 inches is not absolute. Consider this example: For welding 1/8 inch of mild steel, you will need 125 amps.

With that in mind, if you were welding a sheet that was 3/8 inches thick, you will need 375 amps (125 x 3), but instead, most welders claim to do it with just 170-200 amps settings.

According to professionals, there are two reasons for this disparity or ambiguity. First, the numbers you calculate are not accurate estimates but rough figures that give you an idea of what amperage you will be needing.

Secondly, professional welders use certain tricks to gain higher performance which includes beveling the edges of the joint to get thickness down, which can help you achieve the same weld with less current.

Relation of Voltage and Amperage

Generally speaking, there are two kinds of welders you can get in the market when it comes to MIG welding.

The smaller or portable welders that are used for lightweight applications can produce up to 140 amps.

On the other hand, heavy-duty MIG welders operate on 220 volts, which allows them to generate around 200 amps.

You can weld a steel sheet with a material thickness of ¼ inch with a 115-volt welding machine and a steel sheet of ½ inch thickness with a 220-volt one.

One of the disadvantages of a 220v welder is that it cannot operate on lower amperages.

So, if you have a task at hand which requires lower amperage, then you will have to opt for a smaller MIG welder.

Joint Configuration and Positioning

Believe it or not, joint positioning and configuration also impact the amperage of a MIG welder.

Different joint types such as butt joints or lap joints might require a tweak in the amperage settings to achieve the best results.

Hence, to ensure proper fusion and penetration of the joint, you will have to alter the voltage, even though the thickness of the material is the same as before.

Adding to this, the welding positions such as flat, vertical, or overhead can also require adjustments in the amperage based on the specific dynamics of the welding project.

Related: How to Use a MIG Welder?—Ultimate Guide & Expert Tips

Benefits of High Amperage MIG Welders

There are a lot of benefits when you purchase a high-amperage welder. They are more versatile and provide you with a much wider welding application.

First of all, you have the option to boost up the amperage which means more heat input and deeper penetration. Hence, you will be able to weld much thicker sheets of metal as compared to a low-amperage welder.

Secondly, when you become proficient in their usage, you will be able to get much cleaner and more consistent welds. Also, the speed of welding will be much faster.

In simple words, you just have more options on your hands. The wire feeder capacity is higher, you have a bigger spool gun, and you can take care of much more complex projects.

Fine-Tuning Amperage Settings: Factors that are Influenced by Amperage

While amperage itself is influenced by many factors, it too is responsible for making decisive impacts on other welding parameters.

For example, the welding technique and travel speed you will be using are highly dependent on the amperage.

Whether you will be pushing or pulling the weld bead and how the heat will be distributed is determined by what amperage you are proceeding with.

Similar to this, the travel speed of the welding gun is also directly related to the amperage. When amperage is set at high levels, you have to maintain a high travel speed to attain consistent and reliable welds.

Moving too slow will not only ruin the welds but will also cause excessive heat exposure leading to burn-out.

High amperage also requires you to select a thicker wire diameter to ensure proper melting and deposition.

Similarly, when you are working in lower settings, you will have to use a thinner wire diameter for the wire electrode.

Adjustments to the proportions of the gas mixture may also be required depending on the specific amperage.

All of these settings are fine-tuned based on amperage. While a chart or online tool may give you a rough idea of where to start, they will never be able to provide you with a specific number that works for every project.

The needs of every welding project are different, and you will have to adapt to them as you practice.

Common Issues with Amperage in MIG Welding

The amperage settings might present you with some challenges if they are not set right.

Let’s take a look at some of the most common issues you might face if you have got the amperage wrong on your MIG welder.

First of all, if there are burn-through or warping problems, they are probably because the amperage is set too high. So, the welder will melt through the base material.

To avoid this problem, you have to reduce the amperage and adjust your welding technique.

On the other hand, if you are not getting enough penetration for a proper fusion, it might be because of inadequate amperage.

So, you will have to increase the amperage and adjust the travel speed accordingly to get optimal welding results.

Adding to this, inconsistencies in weld quality like uneven bead appearance or lack of proper fusion can also result from amperage issues.

Troubleshooting these issues is important because it will allow you to adjust the amperage within appropriate limits and ensure the achievement of uniform and reliable welds.

Related: What Gas Does a MIG Welder Use? Role of Gas in MIG Welding

Frequently Asked Questions

How many amps do I need for MIG welding?

Well, the answer depends on many factors including the type of material being welded, of material, and the specifics of the welding project. However, as a general rule, for every 0.001 inch of steel, you need to increase 1 amp of power.

How many amps does a 220v MIG welder draw?

Contrary to what you might believe, a 220v MIG welder draws only half the amperage of a 110v MIG welder. So, considering that it is common for a 220v welder to draw about 90-100 amps of power from your circuit.

Do MIG welders use a lot of electricity?

Yes, MIG welders do use a lot of electricity, but it really depends on the usage. If you are using short-circuit transfer, it will use comparatively less power as compared to spray transfer which only occurs at high amperage.

How much power does a MIG welder consume?

MIG welders can consume anywhere from 2000 to 8000 watts of power depending on the specific output of the welder. High-powered MIG welder machines that have industrial applications might consume even more power.

Are 20 amps enough for a welder?

Well, if you are running a 110V MIG welder, then a 20-30 amps power draw can suffice. Yes, you will be drawing a lot of power. However, if you are using a 220V welder, then you will need more amperage.

What is the normal amp for welding?

Normally a 200-amp range is considered enough for a welder. It allows you to take care of a wide range of tasks and welding applications. You can set the welding amperage as per the specific requirements of the task.

What voltage is MIG welding?

The voltage can vary depending on the specifics of the welding project. For welding a thin sheet of steel, you will need a much lower voltage at DCEP, as compared to welding a thicker sheet.

How thick can 160 amps weld?

It has a lot of power that is excellent for welding all sorts of metal. You can weld heavy gauge shields up to ¼ inch thickness with 160 amps. This amperage can be used on both 120- and 240-volt welding machines.

Wrapping Up!

To sum it all up, the specific amperage used by a MIG welder is not absolute and depends on various factors.

Mastering the amperage control is the key to unlocking your full potential as a welder.

Understanding the key concepts behind amperage control and the knowledge of influencing factors will help you gain precise control of the welding process.

If you still have some questions, drop them in the comments section below and I will get back to you as soon as I can. Happy Welding!

Sheila James

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