7018 Welding Rod Amperage Chart – The Definitive Guide For Perfect
For most DIY projects, a 1/8″ 7018 rod performs best between 110 and 165 amps, while a 3/32″ rod typically requires 70 to 100 amps. Always use DCEP (Direct Current Electrode Positive) for the smoothest arc and maximum penetration.
Adjust your settings based on metal thickness and welding position; for instance, reduce your amperage by 10-15% when moving from a flat position to a vertical up weld to prevent the puddle from sagging.
Finding the right 7018 welding rod amperage chart is the first step toward achieving professional-grade beads that are both strong and aesthetically pleasing. Whether you are repairing a tractor bucket or building a heavy-duty workbench, the 7018 rod is the “gold standard” for structural work. However, its low-hydrogen coating makes it a bit more finicky than your average 6011 or 6013 rod.
You have likely experienced the frustration of a rod sticking to the workpiece or an arc that spatters like a frying pan full of water. These issues almost always stem from incorrect amperage settings or improper polarity. This guide will help you dial in your machine so you can stop fighting your equipment and start laying down “stack-of-dimes” welds.
In the following sections, we will break down the ideal settings for various rod diameters, explain how position changes your heat requirements, and troubleshoot common issues. By the end of this article, you will have a clear understanding of how to use a 7018 rod to its full potential in your home workshop.
How to Read a 7018 Welding Rod Amperage Chart
A 7018 welding rod amperage chart is more than just a list of numbers; it is a roadmap for your welding machine’s output. These charts usually provide a range because every welding machine is calibrated slightly differently. An old transformer-based “tombstone” welder might run “colder” at 125 amps than a modern digital inverter machine set to the same number.
When you look at a chart, you will notice that the amperage increases with the diameter of the rod. This is because a thicker rod has a larger steel core that requires more energy to melt. If you run a thick rod at low amperage, the arc will be unstable and the rod will likely stick. Conversely, running a thin rod at high amperage will cause the flux coating to char and fall off, ruining the weld shield.
Most charts assume you are welding in the flat position on clean, mild steel. If you are welding thin-gauge metal or working in a vertical position, you will need to adjust toward the lower end of the recommended range. Always treat the chart as a starting point, then fine-tune your settings based on the behavior of the puddle.
Breaking Down the 7018 Classification
To understand why the amperage matters so much, we need to look at what “7018” actually means. The “70” stands for 70,000 psi of tensile strength. The “1” indicates that the rod can be used in all positions (flat, horizontal, vertical, and overhead). The “8” refers to the low-hydrogen, iron-powder coating.
That iron powder in the coating makes the rod “drag-able,” meaning you can often keep the tip of the rod in light contact with the metal. This coating also requires a higher current to maintain a stable arc compared to cellulosic rods like the 6010. This is why a 7018 welding rod amperage chart often lists higher values than you might expect for other rod types.
The Essential 7018 Amperage Reference Guide
For most garage tinkerers and DIYers, three sizes of 7018 rods cover 95% of all projects. Below are the standard amperage ranges you should keep taped to the side of your welding machine. These settings assume you are using DCEP (Direct Current Electrode Positive), which is the preferred polarity for these rods.
- 3/32″ Diameter: 70 – 110 Amps (Ideal for 1/8″ to 3/16″ thick material)
- 1/8″ Diameter: 110 – 165 Amps (The most common size for structural DIY work)
- 5/32″ Diameter: 150 – 220 Amps (Used for heavy plate, 1/2″ thick or more)
- 3/16″ Diameter: 200 – 300 Amps (Industrial applications and very thick heavy equipment)
If you are using a rod labeled 7018-AC, you have the option to run on Alternating Current. This is common for older home-shop welders that do not have a DC rectifier. While the amperage ranges remain similar, you may find that you need to stay on the higher side of the range to keep the arc from extinguishing as the current cycles.
Keep in mind that the duty cycle of your machine might limit your ability to run 5/32″ or larger rods. Most 110v/120v household welders struggle to put out more than 90-100 amps consistently. For those smaller machines, sticking to a 3/32″ rod is usually the most successful path.
Factors That Change Your Amperage Settings
While the 7018 welding rod amperage chart provides a solid baseline, real-world conditions often require manual adjustments. The most significant factor is the welding position. When welding flat, gravity helps the molten puddle stay in the joint, allowing you to run “hotter” for better penetration and speed.
When you move to a vertical-up weld, gravity works against you. If your amperage is too high, the puddle will become too fluid and drip out of the joint, a phenomenon known as “grapes” or “curtain-ing.” In these cases, you should drop your amperage by about 10 to 15 percent. This allows the puddle to freeze faster, supporting the next layer of weld metal.
Another factor is material thickness and heat soaking. If you are welding a small piece of steel, it will heat up quickly as you progress. You might start the weld at 130 amps, but by the time you reach the end, the metal is so hot that the weld begins to undercut. Experienced welders often “pedal” the heat by moving faster or slightly increasing their arc length as the workpiece saturates with heat.
The Role of Arc Length
In stick welding, your arc length (the distance between the rod tip and the metal) actually affects the voltage. A 7018 rod likes a very tight arc. If you pull the rod too far away, the voltage increases, the arc becomes unstable, and you risk introducing porosity (tiny holes) into your weld.
By keeping a tight arc, you ensure the low-hydrogen flux can properly shield the molten puddle. If you find the rod is sticking even when you are within the chart’s range, try increasing your amperage by 5-point increments rather than long-arcing the rod to get more heat.
How to Dial in Your Welder for 7018 Rods
Before you start your actual project, you should always run a “bead on plate” test. Grab a scrap piece of steel that is the same thickness as your project. Set your machine to the middle of the range suggested by the 7018 welding rod amperage chart. Strike an arc and observe the behavior of the slag and the puddle.
If the arc sounds like a gentle hum and the slag peels up on its own as it cools, you are in the “sweet spot.” If the arc is loud, violent, and throwing sparks everywhere, your amperage is likely too high. On the flip side, if the arc is difficult to start and the puddle looks “mushy” and doesn’t flow into the edges, you need to turn the heat up.
Pay close attention to the shape of the bead. A bead that is tall and skinny indicates the metal didn’t get hot enough to flow. A bead that is flat and has “undercut” (grooves eaten into the base metal at the edges) indicates too much heat. Your goal is a smooth, slightly rounded profile that blends into the base metal seamlessly.
Polarity Matters: Why DCEP?
Most 7018 rods are designed to run on DCEP (Direct Current Electrode Positive), also known as “reverse polarity.” In this configuration, the electricity flows from the workpiece into the rod. This concentrates about two-thirds of the heat at the electrode tip, which is necessary to melt the heavy iron-powder coating of the 7018.
If you accidentally run 7018 on DCEN (Electrode Negative), you will experience a shallow, fluttering arc and poor penetration. Always double-check your lead connections. The “stinger” or electrode holder should be plugged into the positive (+) terminal, and the ground clamp should be on the negative (-) terminal.
Common Pitfalls When Using 7018 Rods
Even with a perfect 7018 welding rod amperage chart, things can go wrong. The most common issue with 7018 is moisture contamination. These are “low-hydrogen” rods, meaning the coating is designed to keep hydrogen out of the weld. Hydrogen causes cracking in high-strength steel.
If a 7018 rod sits out in a humid garage for a few days, the flux will absorb moisture. When you try to weld with it, that moisture turns into steam, causing “pockmarks” or porosity in your weld. For critical structural repairs, professional welders keep their rods in a rod oven at 250°F. For the hobbyist, buying smaller, vacuum-sealed cans and using them immediately is the best practice.
Another pitfall is the “re-strike.” Once you stop welding with a 7018 rod, a small glass-like bead of slag forms over the tip. If you try to strike the arc again, nothing will happen because that slag acts as an insulator. You must tap the tip of the rod against a hard surface or use your file to break that glass tip off before you can start the arc again.
Dealing with Arc Blow
When welding with DC current at higher amperages, you might encounter arc blow. This is when the magnetic field created by the current pushes the arc away from where you want it to go. It often happens near the ends of a joint or in tight corners.
To combat arc blow, you can try moving your ground clamp to a different location on the workpiece. If that doesn’t work, slightly reducing your amperage or shortening your arc length can help stabilize the arc. In extreme cases, switching to an AC-compatible rod (7018-AC) and using Alternating Current will eliminate arc blow entirely.
Workshop Safety and Material Prep
Welding with 7018 produces more smoke and fumes than many other rods due to the iron powder and flux composition. Always weld in a well-ventilated area or use a fume extractor. Because you are running at higher amperages, the UV radiation is also more intense; ensure your welding hood is set to at least shade 10 or 11, and wear leather sleeves to protect your skin from “welder’s sunburn.”
Material preparation is non-negotiable with 7018. Unlike a 6010 rod, which can “dig” through rust and paint, the 7018 requires clean metal. Use a flap disc or a wire wheel to grind the joint down to shiny silver steel. Any rust, oil, or mill scale left on the metal will lead to slag inclusions and a weakened weld.
Finally, always ensure your ground clamp has a solid connection. A weak ground will cause your amperage to fluctuate, making it impossible to maintain the steady puddle you need. If you are welding on a table, grind a small spot clean specifically for the ground clamp to ensure maximum current flow.
Frequently Asked Questions About 7018 Amperage
Can I run 7018 on a 110v welder?
Yes, but you are generally limited to 3/32″ rods. Most 110v household outlets can only provide enough power to run up to 80-90 amps before tripping a breaker. Since a 1/8″ rod needs at least 110 amps, it will likely stick or produce a “cold” weld on a standard household circuit.
What happens if my amperage is too high?
If you exceed the range on the 7018 welding rod amperage chart, the rod will begin to glow red hot before you finish the weld. This ruins the flux coating, causes excessive spatter, and creates “undercut,” which weakens the joint by eating away the base metal.
Is 7018 better than 6011 for DIY projects?
It depends on the project. 6011 is better for rusty metal and deep penetration on dirty steel. 7018 is better for clean steel where strength and appearance are the priorities. Most pros use 6011 for the “root” pass and cap it with 7018 for a strong, clean finish.
Why does my 7018 rod keep sticking?
Sticking is usually caused by one of three things: amperage that is too low, a “cold” workpiece, or a dirty tip. Increase your heat by 5-10 amps, ensure you have broken the slag off the tip of the rod, and use a “match-strike” motion rather than a “pecking” motion to start the arc.
Final Thoughts on Mastering the 7018 Rod
Mastering the 7018 rod is a rite of passage for any serious DIY metalworker. It is a versatile, high-strength tool that, when used correctly, produces welds that are as beautiful as they are strong. By keeping a 7018 welding rod amperage chart handy and understanding the variables that affect your heat, you take the guesswork out of your projects.
Remember that welding is a “seat time” skill. No amount of reading can replace the feeling of the rod melting into the plate. Don’t be afraid to experiment with your settings—turn the dial up until it’s too hot, then back it down until it’s too cold. This “bracketing” technique will help you recognize the perfect arc by sight and sound.
Stay safe, keep your rods dry, and always prioritize clean metal. With these practices and the right amperage settings, your workshop projects will transition from “hobbyist” to “professional” in no time. Now, grab your hood, strike an arc, and get to work!
