MIG Welding Electrodes Wire Selection Guide

This is a detailed page about MIG welding wire selection. It covers most electrodes that are commonly used in the field for:

  • Carbon steel
  • Stainless steel
  • Aluminum
MIG Welder Electrode ESAB
MIG Welder Electrode

Most Widely Used MIG Welding Electrode Sizes

Typical MIG welding electrodes are a solid wire ranging from a thickness of .023 to .045. Some are much thicker for heavy industrial applications. The most common sizes most welders use are:

  • .023
  • .030
  • .035
  • .045

For most fabrication shops the .035 with is the most common. If you are a at home welder then use a small diameter electrode whenever you can. The smaller the electrode the less power you need from your machine to run. Just remember when it comes to MIG welding a single electrode size welds a wide range of metal thicknesses because it is the machine set-up that determines the metal thickness that will be welded.

MIG Welding Electrode Wire Selection Guide Chart

MIG Welding Electrode Selection Chart
MIG Welding Electrode Selection Chart
Lincoln MIG Welding Electrode and Gas Selection Chart Settings
Lincoln MIG Welding Electrode and Gas Selection Chart Settings
Welding Carbon Steels and Mild Steels
  • AWS Electrode Classification: ER70s-6
  • Shielding Gas: C25 (25% Carbon Dioxide and 75% Argon) or 100% Co2
Welding Stainless Steel

Stainless Steel Grades: 301, 302, 304, 305, and 308.

  • AWS Electrode Classification: ER308L and ER308LSi
  • Shielding Gas: C2 or 2% Carbon Dioxide and 98% Argon

Stainless Steel Grades: 309 Stainless and
Welding Carbon Steel to Stainless Steel or Low Alloy Steels

  • AWS Electrode Classification: ER309L
  • Shielding Gas: C2 or 2% Carbon Dioxide and 98% Argon

Stainless Steel Grades: 304,305, 308, 310, 312, 314, 316, 317, 321, 347 and 348.

  • AWS Electrode Classification: ER316L and ER316LSi
  • Shielding Gas: C2 or 2% Carbon Dioxide and 98% Argon
Welding Aluminum

Aluminum Grades: 2014, 3003, 3004, 4043, 5052, 6061, 6062 and 6063. It may also be used to weld cast Aluminum grades 43, 214, 355 and 356.

  • AWS Electrode Classification: ER4043
  • Shielding Gas: 100% Argon

Aluminum Grades: 5050, 5052, 5056, 5083, 5086, 5154, 5356, 5454, 5456.

  • AWS Electrode Classification: ER5356
  • Shielding Gas: 100% Argon

Carbon Steel Electrode Selection and Choices

MIG Welding carbon steel or mild steels are typically welded with a ER70s-6" electrode using either 100% Carbon Dioxide gas or C25 gas that is 25% Carbon Dioxide and 75% Argon mixture. If you are welding a higher grade of carbon steel the minimum tensile strength is what usually changes. For example if you are welding high strength steel the “ER70S-6" would be a “ER90S-6" instead. The change in the strength of the steel is what would be different.

Mild steel weld done with a ER70S-6 electrode and C25 gas.
Mild steel weld done with a ER70S-6 electrode and C25 gas.
Carbon Steel ER70S-6 Electrode Designation
The label ER70S-6 represents the following:
  • ER– An electrode or filler rod that is used in either a MIG wire feed or TIG welding.
  • 70– A minimum of 70,000 pounds of tensile strength per square inch of weld.
  • S -Solid wire.
  • 6– The amount of deoxidizing agent and cleansing agent on the electrode. This is a copper coating on the electrode and there are different types too.
MIG Wire Electrode Label Meaning for a  ER70S-6 Label
MIG Wire Electrode Label Meaning for a ER70S-6 Label

Stainless Steel MIG Welding Electrode Selection and Choices

MIG welding stainless steel has a variety of electrodes because it is used on a wide range of projects that require different types of stainless steel grades. It is also commonly welded to Carbon steel on the same jobs. For example a stainless steel brace that is welded to the building that holds stainless steel piping. Here are the different types of stainless steel electrodes. Stainless Steel is typically welded with the electrode classes and they are:

  • ER308L
  • ER309L
  • ER316L
ER308L and ER308LSi MIG Welding Electrode Designation and Uses
These stainless electrodes are mostly used for lower grade stainless steels 301, 302, 304, 305, and 308. This is not the shiny stuff most people think of as stainless steel. It is typically used in industrial applications and it does get some rust spots from time to time. The picture on the left is a 304 stainless steel welded with a ER308L series wire. The wire designation is as follows:
  • ER– An electrode or filler rod that is used in either a MIG wire feed or TIG welding.
  • 308 – The grade of the Stainless Steel Electrode.
  • L –Low Carbon. Carbon content is what gets the rust spots on stainless.
  • Si– (Optional) Sometime “Si" is added and that means high silicone content. Basically it helps the weld wash into the metal better. Kind of like turning up the heat and holding the sides longer.
Stainless Steel MIG weld done with a 308L electrode C2 gas.
Stainless Steel MIG weld done with a 308L electrode C2 gas.
ER309L and ER309Si MIG Welding Electrode Designation and Uses (Welding Dissimilar Metals)

The 309 series has a multi use designation because it is used to weld stainless steel to mild or stainless to carbon or low alloy steels. It welds stainless steel grades 304 through 310 when needed or welds dissimilar metals together where needed. The downside of using this electrode to weld steel to stainless is that the weld appearance is rough. It does the job but no matter how high you turn up the machine it feels like it is running cold. No matter what you do the welds seems to look rough compared to welding stainless steel to stainless steel. The gas used most of the time is the same C2 or 2% carbon dioxide and 98% Argon. There are many other choices (some are better) for gas but the C2 is the most common used. Here is the electrode designation:

  • ER– An electrode or filler rod that is used in either a MIG wire feed or TIG welding.
  • 309 – The grade of the Stainless Steel Electrode.
  • L –Low Carbon.
  • Si– (Optional) Sometime “Si" is added and that means high silicone content. Basically it helps the weld wash into the metal better. Kind of like turning up the heat and holding the sides longer.
ER3016L and ER316LSi MIG Welding Electrode Designation and Uses

These stainless electrodes are mostly used for higher grade stainless steels mainly in the food industries and marine applications. The base metals the ER316 welds are stainless grades 304,305, 308, 310, 312, 314, 316, 317, 321, 347 and 348. As for gasses the C2 (2% carbon dioxide and 98% Argon) is the most widely used. There are many other mixtures to choose from and that all depends on you welding supplier has to offer. The wire designation for the ER316L and the ER316LSI are as follows:

  • ER– An electrode or filler rod that is used in either a MIG wire feed or TIG welding.
  • 316– The grade of the Stainless Steel Electrode. This is food grade and true marine grade. But nowhere the best grade of stainless.
  • L –Low Carbon. Carbon content is what gets the rust spots on stainless.
  • Si– (Optional) Sometime “Si" is added and that means high silicone content. Basically it helps the weld wash into the metal better. Kind of like turning up the heat and holding the sides longer.
Aluminum MIG Welding Electrodes Choices and Wires

MIG welding aluminum electrodes selection is pretty straight forward. There are two typical choices and they are:

  • ER4043
  • ER5350

Now there are other choices but is rare to need any other electrodes. As for gas choices it is always 100% Argon gas. If you are welding aluminum thicker then 1/2 of an inch then you may want to try a Argon Helium mix. In most cases 100% Argon is what most shipyards, power plants and fab shops use no matter what the thickness of the aluminum is. Here are the aluminum electrode designations:

ER4043 MIG Welding Electrode Designation and Uses

The ER4043 is the most commonly used MIG filler wire. It welds aluminum grades 2014, 3003, 3004, 4043, 5052, 6061, 6062 and 6063. It may also be used to weld cast aluminum grades 43, 214, 355 and 356. The gas used is always 100% Argon and in rare cases a helium/Argon mix may be used on base metals thicker then ½ of a inch. Electrodes classification and designation is as follows:

  • ER– An electrode or filler rod that is used in either a MIG wire feed or TIG welding.
  • 4– The series of the aluminum. This electrode is made from a 4000 series aluminum.
  • 043 – This number indicates the amount of silicone added to the electrode. 4000 series of aluminum alloys have silicone added to make that grade.
ER5350 MIG Welding Electrode Designation and Uses

The ER4043 is the most commonly used MIG filler wire. It welds aluminum grades 5050, 5052, 5056, 5083, 5086, 5154, 5356, 5454, 5456. In most cases the gas used is always 100% Argon and in rare cases a helium/Argon mix may be used on base metals thicker than ½ of a inch. The electrodes designation is as follows:

  • ER– An electrode or filler rod that is used in either a MIG wire feed or TIG welding.
  • 5– The series of the aluminum. This electrode is made from a 5000 series aluminum.
  • 356 – This number indicates the amount of Magnesium added to the electrode. 5000 series of aluminum alloys have Magnesium added to make this alloy.

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