How to MIG Weld Stainless Steel

MIG welding has a place in various types of projects, from home improvement to automotive projects. On top of that, MIG welding is capable of dealing with stainless steel, a reliable and solid choice for many jobs. While it might seem as if going with a professional is the best choice, it is actually not that difficult to do it yourself.

Instead of depending on a technician to MIG weld stainless steel, purchase a MIG welder at your local tool supply store along with the other pieces of equipment required to complete the project. With a basic knowledge of welding and the detailed instructions in this article, you will be MIG welding stainless steel like a professional in no time.

The Fundamentals of How to MIG Weld Stainless Steel

Stainless steel is one of the more hearty metals, so those with minimal welding experience wonder if it is even a possibility. The answer is yes, with the correct devices and methods. What you need to remember is not to get frustrated. Chances are they will not be flawless the first time, so be prepared to make numerous attempts.

To begin welding stainless steel, dive deeper into the detailed steps below, which include more specifics on the tools and materials required, MIG weld methods, alternative options, and ways to avoid some of the most common mistakes. You will be satisfied after learning just how straightforward it is.

Gather MIG Welding Tools and Other Consumables

Before learning how to MIG weld stainless steel, it is critical to have the right equipment, welding consumables such as wires, contact tip, nozzle, retaining head, and other materials. Everything you need can be purchased online, in most big box stores, or at your local tool supplier.

Use this handy checklist to make sure you are fully prepared for doing the best MIG welds to stainless steel:

Shielding Gas: Tri-mix is the preferred shielding gas according to most experts, but there are alternative options (keep reading for more details on shielding gasses).
Welding Wire: Only stainless steel welding wire is appropriate. Welding wires come in a variety of diameters and must be cut to length.
MIG Welder: Find one that offers the necessary features required for stainless steel weldings like sample stainless steel wires and a proper welding gun.
Wire Feeder: Provides greater control of the feed rate for better welds overall. Not essential, but a good idea if you plan to do a lot of welding projects.
Welding Gun and Replacement Tips: Your MIG welder should come with a welding gun, but there are different choices for more specific project types. Welding gun tips wear out with use, so have a few extra on hand.
Gun Liner: Convenient to cover the welding gun and allows for quick changes between different types of jobs and assorted kinds of metal wires.
Metal Brush: For cleaning and prepping the work area.

If you have acquired the materials or already had them at home, you are now ready for the next step.

Prepare the Metal Before MIG Welding Begins

The final result you are expecting is a clean weld that is free from inconsistencies or cosmetic blemishes. You also desire a weld that is durable and will hold under the related-use conditions.

The last thing you want is to watch your weld fail and an expensive piece of material be destroyed. To achieve a clean weld that is blemish-free, you must be sure to:

  • Clean the stainless steel piece you are going to work on with a clean and sturdy metal brush. Be sure to remove all dust, dirt, oil, and other contaminants that could interfere with your welds. Even the smallest piece of debris can cause erratic welds, which can ruin all of your effort in an instant.
  • Clean the work table, bench, or project area with the metal brush after your stainless steel is done as well. It is just as vital that the site is dry, so either wipe it down with a dry cloth or give it time after cleaning.

One of the easiest ways to mess up an otherwise clean MIG weld is by skipping over the critical cleaning step. Not only could you be left with a bumpy or unreliable weld, but it can also cause unwanted weld splash that could potentially cause burns on unprotected skin. Since this involves safety as well as the final product, do it well.

Select the Proper Welding Wire and Shielding Gas

Welding wire comes in a wide array of diameters. For most MIG welds on stainless steel, .030-inch is the appropriate choice. However, the best choice is to take a look at the piece you are welding to be sure.

If you discover what you are welding has a thicker base, there are other alternatives that range from .035-inch to .045 inches. Those may be what you want to ensure a long-lasting and durable finish.

The tri-mix shielding gas that has been brought up is the most suitable choice for MIG welding stainless steel. The mixture provides benefits, including an increased amperage for quicker welds without the undesired, more extreme heat. Once again, this is something that can affect both the final product and safety, so pay close attention.

The Proper Shielding Gas for Mig Welding Stainless Steel

There is a smaller concern for messy pool welds. Tri-mix shielding gas and other kinds are broken down even further below.

Types of Shielding Gas for Mig Welding Stainless Steel
Tri-Mix (Best Choice)AlternativeAlternative
90% Argon98% Argon98% Argon
7.5% Helium2% CO22% Oxygen
2.5% Oxygen
Types of Shielding Gas for Mig Welding Stainless Steel

While all of these shielding gases work, there are certain factors that can influence which is best. Therefore, before you decide which shielding gas to apply to your upcoming stainless steel job, you want to take into consideration factors like:

  • The productivity goals you have in mind
  • The process for the weld transfer
  • The price of the shielding gas
  • Prep and clean up demands
  • Your base material

Discuss what is available with the supplier in your area. Tri-mix is ideal, as suggested, but the alternatives are satisfactory for most projects. Pick what works best for you and what is available, even though it might be worth looking for a tri-mix if you are not in a rush.

MIG Weld the Stainless Steel

Think back to when you were younger playing sports, learning an instrument, or developing skills in any area. What were you always told? Practice makes perfect! MIG welding stainless steel is no different. It will require several attempts and a few mistakes along the way to figure it out.

One suggestion is to gather some scrap stainless steel to work on your weld methods and technique first before jumping into something more complex and permanent. That way, if you do make an error, you will not be so ready to give up. More importantly, there is no loss of investment on the part you need.

Travel Angles in MIG Welding

Before you can decide what travel angle to implement, comprehension is key. The travel angle is where the gun is in a vertical positioning from the piece you are welding. For most welding projects, a 5 to 15-degree angle is used.

Anything beyond 20 to 25 degrees will create a more significant weld splatter, instability of the arc, and less penetration.

MIG Welding Work Angles in Flat Positioning

Work angles are different from travel angles and refer to the position of the welding gun. Some of what you should keep in mind is:

  • Lap Joint or Fillet Weld: Position the gun at a 60 to 70-degree angle. For thicker metal, use the higher angle.
  • T-Joint: Position the weld gun in the middle of each piece or at a 45-degree angle.
  • 180-Degree Butt Welds: Position the gun at 90-degrees and push the welding wire directly into the joint. Incorporate a 5 to 15-degree travel angle.

Be mindful as you work since the angles may shift slightly in either direction. It is the only way to avoid undercuts and weld beads.

In the instance you are doing MIG welds in a horizontal position, your work angles need to be adjusted anywhere from 0 to 15 degrees to account for gravity. However, the travel angles will remain the same.

Push Method vs. Pull Method in MIG Welding

There are two different techniques for MIG welding, including a push method and a pull method.

  • The push method is what you will use most often and whenever possible. The arc force gets directed away from the weld puddle utilizing this technique. You will push the welding gun in front of or away from the weld puddle. It is how to accomplish wider beads that are flatter with a lesser penetration.
  • The pull method is more for welds that require a deeper penetration in the material. The end result also is typically more narrow with a more elevated buildup of material.

Pushing or pulling during MIG welding of stainless steel can is acceptable and will work when performed correctly. Some prefer the push method because you can see more clearly, and you can more precisely place the wire in the proper positioning. It will take some practice of each to discover which works best for you.

The Best Way to Weld Stainless Steel

According to experienced welders, the best way to weld stainless steel is with a MIG welder and the tri-mix shielding gas. In fact, for some, it is the only way.

Suppose you want to try alternative methods and determine what you are most comfortable with. In that case, you will need an entirely different set of materials and instructions, which can be wasteful if it does not work out. Some reasons why MIG welding is considered to be the best option are:

  • Manual, semi and fully automatic adjustments are available in the supplied setting features
  • MIG welding stainless steel is quicker and, when done correctly, provide higher-quality welds
  • There is no flux core wire required, which tends to get wrapped up in the wire metal slag causing erratic welds
  • Minimal weld splatter
  • Minimal loss of arc because of the composition of the tri-mix gas shield utilized
  • MIG welding can be applied with stainless steel and a wide assortment of other metals

Of course, nothing is entirely flawless all the time, and there are a few cons or disadvantages associated with MIG welding stainless steel, including:

  • Somewhat complex equipment operations if you are not familiar
  • Higher fluidity of weld puddling because of the heat
  • Inability to use MIG welding for overhead or vertical positions

There are other possibilities for welding stainless steel, but for small repairs and occasional welding projects, MIG welding is the most popular option.

Other Available Options for Welding Stainless Steel

Besides what we have been covering so far with MIG welding, otherwise known as shielded metal arc welding, there is another option for welding stainless steel. Each technique will end in different finishes.

  • MIG Welding: when efficiency and speed are imperative
  • TIG Welding (gas tungsten arc welding): when appearances are essential

Factors to consider when choosing which technique to use are:

  • Your level of familiarity with welding
  • How much you want to spend
  • The time you have to get it done
  • What you want the bead to look like
  • How thick the metal is that you are welding

While MIG weldings speed and efficiency are what really matter for most jobs, there are times when appearances are the prime concern. Therefore, it is important to make sure MIG welding is the best option for you before putting your time and energy into a project.

Common Mistakes and Ways to Avoid Them When When Mig Welding Stainless Steel

While MIG welding stainless steel can be extremely productive and useful in numerous projects, there are also risks for error and separate complications. Avoid spending unnecessary funds on replacing consumables or other materials by being aware of some of the most frequent issues and how to prevent them.

  • Poor Grounding: Improper grounding leads to unpredictable arcing and heat issues. Place the grounding as close to your piece as you can and attach it to a weldment or bench if you can. The closer you can get the ground to the arc, the more efficient it will be.
  • Using the Wrong Welding Gun: Check the amperage capacity and duty cycle to ensure it is sufficient for the job. Selecting one that cannot keep up will lead to earlier and more frequent breakdowns and replacements.

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  • Cable Management Issues: Do not pull on the MIG welder by the cable. It is hot and more resilient when you are using it. It will eventually bend, break, or become otherwise damaged. Shielding gas issues are common when pulling on the cables as well because you can pull it apart from the gas pin.

Even storing the welding gun can end up being a problem if done improperly. Never drape the welding gun by the wire because it will bend the warmed cables. Always keep it laid flat when not in use.

Mistakes Involving Wire

Mistakes and problems involving the wire are common, especially when you do not use the proper wire for the job. A few of the common problems associated with wire are:

  • Incorrect Wire Length: Along with selecting the correct weld wire diameter, you have to cut it to the right size for premium wire feeding and arcing. Use a liner gauge or one of the error-proof systems available.
  • Improper Wire Feed Speed or Voltage: Results can be unstable weld arcing. Voltages that are too high create too much heat, while speeds that are too fast will end in a pile of wire instead of a weld pool. Look at the specifics outlined by the manufacturer of the MIG welder and the type of metal for the correct settings.
  • Problems with the Drive Roll: match the drive roll tension with the type and size of weld wire to avoid ineffective wire feeding.

As stated earlier, make sure to use the right size of wire to make the job easy and successful.

Taking Care of Your MIG Welding Supplies for the Greatest Life Expectancy

You have to adequately maintain your welding equipment to prevent these common problems, avoid making mistakes, and create the most durable welds. This includes the nozzle, welding wire, and contact tip. Check that they are clean and free from debris whenever you change any of the consumables.

Before starting in on any welding project, make sure that all your lines are tight and in-tact. Keep wires level for cooling after use and between welds to ensure your MIG gun runs at optimum efficiency.

What to Remember When MIG Welding Stainless Steel

There are a few fundamental basics to remember when you are MIG welding stainless steel. Most importantly, you have to be sure to have the appropriate tools, including the right shielding gas and welding wire that is purpose-specific for stainless steel. 

Do not get frustrated with your welds either. It is challenging to get the perfect results the first time. Be patient, and be willing to practice. It is a skill that evolves over time. As long as you have the right tools and mindset, you will be MIG welding like you have been doing it for years before you know it.

Sources:

https://www.homedepot.com/c/ah/how-to-weld-stainless-steel/9ba683603be9fa5395fab9014a903126

https://www.millerwelds.com/resources/article-library/mig-welding-the-basics-for-mild-steel#:~:text=Travel%20angle%20is%20defined%20as,penetration%20and%20general%20arc%20instability

https://www.rodovens.com/index.php/blog/advantages-of-mig-welding/#:~:text=Advantages%20of%20MIG%20welding%20are%3A&text=Since%20a%20flux%20is%20not,minor%20weld%20spatter%20is%20produced

https://www.americantorchtip.com/blog/pros-cons-best-ways-welding-stainless-steel-tig-rust

Alexander Berk

A bit about myself: I am a certified international welding engineer (IWE) who worked in different welding projects for TIG, MIG, MAG, and Resistance Spot welding. Most recently as a Process Engineer for Laser and TIG welding processes. To address some of the questions I frequently got asked or was wondering myself during my job, I started this blog. It has become a bit of a pet project, as I want to learn more about the details about welding. I sincerely hope it will help you to improve your welding results as much as it did improve mine.

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