How do you determine what the standard rod size is?

The most common stick rod diameters are 3/32″, 1/8″, and 5/32,” and these sizes will cover most of your welding projects. However, it would be best if you understood how the selections of these rod sizes relate to the base metal thicknesses and the part they play in achieving a professional-quality weld.

For example, smaller diameter rods--such as 1/16” and 5/64”-- are more complicated to work with than common-size rods. These rods are designed for workpieces thinner than 1/8″, but 1/8” is the thinnest material recommended for stick welding. Rods smaller than 1/8” tend to vibrate at the tip, requiring a steady hand. Also, they are more challenging to find and cost more.

Stick rods 3/16″ and larger are also more challenging to use. They are for the thickest and largest workpieces and require significant experience to get a good weld. They also create large puddles that are hard to control. You will need a welding machine that can output a high amperage, and as the rods get bigger, so do the hazards. More heat, UV rays, fumes, spatter, and noise equal a safety issue.

Base metal thickness

As a rule, you would select a rod that is a size thinner than the base metal. For example, if the base metal thickness is 1/8″, use a 3/32″ rod. This works well on thicknesses up to 3/16” and for standard welds like a one-side single-pass butt weld.

Of course, this rule is not hard and fast since many welding professionals select a rod diameter that is half as thick as the base metal, and they get excellent results. However, if you go with a rod much thinner than that, you risk having a low metal deposition rate.

Choosing a rod with the same diameter as the base metal’s thickness could cause the heat to blow through the metal and create excessive warping. Some novice welders mistakenly pick a rod thicker than the base metal, resulting in too much heat in the joint, making welding nearly impossible.

One exception to the rule applies to very thin metals. For instance, if you are welding 17-gauge (1.4mm) sheet metal, the smallest rod would be 1/16″ (1.6 mm). However, stick welding thin metals is challenging, requiring much experience and giving unsatisfactory results. Veteran welders sometimes use thicker rods on thinner metals since narrow rod diameters are harder to find and costlier.

Also, when the base metal is thicker than 3/16″, it helps to bevel the joint for full penetration and weld it with common-sized rods.

Final thoughts

Deciding on the right electrode for stick welding is relatively straightforward if you remember a few suggestions:

• Consider the type of welding and the base material
• Know what the electrode numbers represent. For example, a 6011-rod number will have a minimum of 60,000 pounds of tensile strength per square inch of weld. 
• The last two digits of the rod number refer to the flux coating on the rod, with higher numbers representing more shielding and more flux or metal being deposited.
• A 6011 electrode is used for standard maintenance and can be used in all welding positions, works on dirty metals, and tolerates an imperfect joint.