Welding Rod Sizes and How to Pick The Correct Size

Welding applications call for different rod sizes. Choosing the right size for a project is a crucial early step, whether a repair job or a new fabrication. Different rods can produce similar results, but it depends on a few trade-offs.

In this article, I’ll cover the most common welding rod sizes to help you pick the most suitable one for your needs.

What Do Welding Rod Size Numbers Mean? 

The most common welding rods or electrodes come in 4-digit numbers, while others are 5-digit figures. Now, these identification numbers aren’t arbitrary. You can get a lot of information by just looking at the series.

Let’s take E7018, for example. Here’s how to break down this number, according to the American Welding Society:

  1. E stands for the electrode.
  2. The first two digits refer to the tensile strength, measured in psi (pounds per square inch). It’s the amount of stress the weld bead can handle. A higher psi means a stronger electrode when welded.
  3. The third digit refers to the welding position.  
  • 1 indicates all positions (flat, horizontal, vertical, overhead)
  • 2 refers to flat and horizontal positions only
  • 3 means flat position only
  1. The last digit shows two things:
  • The current type required
    • AC alternating current
    • DCEP direct current electrode positive (reverse polarity)
    • DCEN direct current electrode negative (straight polarity)
  • Flux composition or type of coating used
    • 0 High cellulose sodium; DCEP
    • 1 High cellulose potassium; AC, DCEP, DCEN
    • 2 High titania sodium; AC, DCEN
    • 3 High titania potassium; AC, DCEP
    • 4 Iron powder and titania; AC, DCEP, DCEN
    • 5 Low hydrogen sodium; DCEP
    • 6 Low hydrogen potassium; AC, DCEP
    • 7 High iron oxide and iron powder; AC, DCEP, DCEN
    • 8 Low hydrogen potassium and iron powder; AC, DCEP, DCEN

If we’re to follow this number classification, an E7018 electrode can withstand 70,000 psi (70) and is suitable for all positions (1). It has a low hydrogen potassium and iron powder coating compatible with all current types (8).

Meanwhile, some electrodes come with additional information provided in the suffix. For example, the electrode EXXXX -1 has the -1 that indicates increased toughness in E7018 electrodes or increased ductility in E7024 electrodes

welding rod sizes

Common Welding Rod Sizes

You’re likely to come across these electrodes the most: E6010, E6011, E6013, and E7018. These are common welding rods used in shielded metal arc welding or stick welding. Each of these electrodes is available in different rod sizes. 

The rod size is the diameter of the core wire and not the total diameter of the shielded or flux-coated rod. 

Different electrodes can have the same size but different overall thicknesses. For example, a 1/8″ E7024 is thicker than a 1/8″ E7014, and a 1/8″ E7018 is thicker than 1/8″ E6013. 

A home welder often uses one of these sizes: 3/32″, 1/8″, and 5/32″. These are the most common rod sizes used in basic applications. 

I have written a guide explaining the differences between the common electrode types of 6010 vs 7018.
ElectrodeCoatingPositionCurrentPenetrationTensile Strength
E6010High cellulose sodiumAll PositionsDCEPDeep60,000 PSI
E6011High cellulose potassiumAll PositionsDCEP
AC
Deep60,000 PSI
E6012High titania sodiumAll PositionsDCEP
AC
Medium60,000 PSI
E6013High titania potassiumAll PositionsDCEP
DCEN
AC
Shallow60,000 PSI
E7018Iron powder low hydrogenAll PositionsDCEP
AC
Shallow to Medium70,000 PSI
E7028Iron powder low hydrogenFlat Horizontal FilletsDCEP
AC
Shallow to Medium70,000 PSI

What Size of Welding Rod Do I Need?

As a general rule, you can use the largest rod size possible when there’s no welding procedure specification. 

Larger diameters deposit more molten material into a weld joint in the least amount of time and at a lower cost. They’re especially preferable when welding thicker plates. 

Here’s a list of the recommended size based on material thickness to give you an idea:

  • 1/16″ electrode for metals up to 3/16″ 
  • 3/32″ electrode for metals up to 1/4 
  • 1/8″ electrode for metals over 1/8 
  • 5/32″ electrode for metals over 1/4 
  • 3/16″ electrode for metals over 3/8 
  • 1/4 electrode for metals over 3/8 
  • 5/16″ electrode for metals up to 1/2″ 

How to Pick the Correct Welding Rod Size

Choosing the rod size depends on a few considerations. Here’s what you should know.

Material Thickness

The general trend is that the thicker the base metal to weld, the larger the electrode size needed. A large-diameter electrode will fill in a thick base metal adequately. It also offers a stable arc on thick materials. 

However, there’s no need to use a large electrode when welding thinner materials.

Ampere settings depend on the electrode type and diameter. The material won’t be able to handle the amperage you need with a large electrode without burning through it. A low-diameter rod can only manage low amperage.

When a large electrode isn’t available, you can run multiple passes with a smaller electrode. This will build up the weld to the desired dimension, but with one major drawback. You risk running into a defect every time you run an additional pass along the joint.

Welding Positions

Larger electrodes are suitable for flat-position welding.

Smaller electrodes provide efficient production in vertical, horizontal, and overhead positions. They produce a smaller weld puddle that solidifies fast behind the travel. The arc is also more controlled with the slow travel speed.

Joint Design

Electrodes have different flux-to-diameter ratios. Different electrodes of the same wire diameter will fit the joint differently.

The rod size, as well as the type, should match the joint design and fit-up. Complicated joint designs and tight fit-ups are tricky. The electrode type and size should provide the most sufficient penetration.

For example, a large electrode doesn’t perform well on groove welds. The diameter should be small enough to get to the root of the joint. It should fill the root gap while also considering the material thickness. 

If you have to do multiple passes with a smaller electrode, the material can distort from the heat. 

Welder’s Skill

The quality and strength of the weld depend on the welder’s skill and the right tools.  

Smaller electrodes are tougher to handle. They tend to shake at the tip a lot. This shouldn’t be an issue with steady, skilled hands. 

Small-diameter electrodes like the 1/16″ are expensive and not widely available. While a smaller rod is preferable, an experienced welder will have no problem welding larger electrodes on thinner sheets.

Risks mount as the diameter increases. Unusually thick materials require electrodes larger than 3/16″. It calls for a lot of experience to weld too. A more skilled operator can control a bigger weld puddle. 

If you’re a beginner, you can start with a large electrode and develop your skills from there. 

Conclusion

Welding rod sizes vary in electrodes of the same diameter. It’s because of the amount of flux or coating each one has. Diameters range from 1/16″ to ¼″, the most common diameters being 3/32″, ⅛″, and 5/32″.

You have to choose the correct size depending on your need, as well as material thickness, welding position, joint type, and skill level.