How to Read Electrode Numbers: 6011, 6013, 7018

Arc welding electrodes (SMAW) carry a four-digit number that looks like a secret code. It isn't: each digit tells you something useful. Once you understand it, picking the right electrode stops being guesswork.

What the four digits mean

• The first two (60, 70): the tensile strength of the deposited metal, in thousands of pounds per square inch (ksi). A 6011 deposits 60,000 psi metal; a 7018, 70,000 psi.
• The third digit (1): the positions you can weld in. 1 means all positions (flat, horizontal, vertical, and overhead). A 2 would mean flat and horizontal only.
• The fourth digit (1, 3, 8): the coating type and what current it runs on. This defines how the arc behaves.

6011: deep penetration

Aggressive arc, digs deep, and burns through rust, paint, and light dirt. Runs on AC or DC. Best for: field repairs, dirty or rusty metal, and root passes where you need deep fusion. It's less beginner-friendly because the arc is harder to control.

6013: the friendliest to start with

Smooth, stable arc, easy-to-remove slag, good finish. Penetrates less than 6011, so it needs clean metal. Best for: learning. If you're practicing your first beads, start here: it forgives more mistakes and the result looks better.

7018: strength and quality

The favorite for structural work. Deposits high-strength, low-hydrogen metal, which reduces cracking risk. It needs to stay dry (stored in an oven or sealed tube). Best for: joints that will carry weight — structures, trailers.

Which one do I buy first?

If you're learning: 3/32" or 1/8" 6013 for practicing on clean metal. Once you've got the arc down, add 6011 for repairs and 7018 for serious work. Buy by the pound based on what you'll weld, not out of habit.

Not sure which size or brand to pick? At RGV Welding Supply we'll point you in the right direction based on your machine and your project — visit us in Pharr or Weslaco.