A lot of people hear the term arc welding thrown around in the shop and never stop to ask what does arc welding stand for or what actually makes it different from other welding processes.
Early on, that confusion is common—especially when you’re jumping between stick welding, MIG vs TIG, and seeing different rods, wires, and machines all doing similar-looking work.
At its core, arc welding is about using an electric arc to generate enough heat to melt the base metal and filler material, but how that arc is controlled makes all the difference. Things like arc control, electrode type, metal thickness, and joint prep directly affect weld quality, strength, and safety.
Understanding what arc welding really means isn’t just textbook knowledge—it helps you choose the right process for the job and avoid costly mistakes. Stick with me, and I’ll break it down in clear, shop-friendly terms that actually make sense.
Photo by zerohourparts
What Exactly Is Arc Welding?
Arc welding is the go-to method for joining metals using electricity to create a super-hot electric arc that melts the base material and any filler you add. Think of it as the backbone of most welding jobs because it’s versatile and doesn’t require fancy setups for basic work.
At its core, it works by connecting a power source—either AC or DC—to an electrode and the workpiece. When you bring the electrode close enough, an arc jumps across the gap, hitting temperatures around 6,500°F.
That heat melts the metal edges, forming a pool where everything fuses as it cools. Shielding comes in to protect the molten area from air contaminants like oxygen or nitrogen, which could weaken the bond.
You’ll use arc welding when you need strong, reliable joints on ferrous metals like steel or iron, especially in construction, automotive repairs, or heavy fabrication. It’s ideal for outdoor jobs where wind might blow away gas shields in other processes, or when portability matters since some setups are as simple as a stick welder and rods.
From the shop floor, always start with a clean surface—grind off rust or paint to avoid porosity. I once had a trainee skip this on a mild steel repair, and the weld bubbled up like popcorn, forcing us to grind it out and redo. Test your arc on scrap first; if it’s sputtering, tweak the amperage down 10-20 amps to stabilize.
How Does the Electric Arc Form and Why Does It Matter?
The arc forms when high voltage ionizes the air between the electrode and metal, creating a conductive path for current. Electrons flow, generating heat mostly at the anode side—about 60% there if you’re on DC positive polarity.
This matters because it affects penetration and bead shape. Deeper penetration means stronger welds on thicker materials, reducing distortion from uneven heating. Use it on jobs like welding 1/4-inch plate where you need full fusion without warping the piece.
In practice, maintain a short arc length—about the diameter of your electrode—to keep control. Too long, and you’ll get spatter everywhere, wasting rod and making cleanup a nightmare. I’ve fixed countless bad welds by showing folks to “listen” to the arc; a steady crackle means it’s right, while hissing points to issues like moisture in the rod.
When Should You Choose Arc Welding Over Other Methods?
Opt for arc welding when versatility trumps speed, like in repair work on farms or job sites with varying materials. It’s not as fast as MIG for production runs but shines in tight spots or vertical positions where gravity fights you.
Why? Because processes like stick welding (a type of arc) let you pause and reposition without losing your shield. For DIYers, it’s cost-effective—no gas bottles to refill. But skip it for thin sheets under 1/8 inch to avoid burn-through; TIG might be better there.
Shop tip: On windy days, stick with SMAW over MIG to prevent gas blowout. I learned this the hard way on a outdoor fence repair; switched rods mid-job and saved the day.
Types of Arc Welding Processes Every Welder Needs to Know
Arc welding isn’t one-size-fits-all; it branches into several processes based on electrodes and shielding. Picking the right one depends on your material, position, and finish needs.
What Is Shielded Metal Arc Welding (SMAW) and How Do You Use It?
SMAW, or stick welding, uses a consumable electrode coated in flux that melts to shield the weld. It’s the classic arc process—simple and rugged.
It works by striking the rod against the metal to start the arc, then dragging or weaving it along the joint. The flux creates gas and slag to protect from atmosphere, and the rod core adds filler.
Use it for heavy repairs on steel structures or pipelines when you need deep penetration. Why? It’s forgiving on dirty surfaces and works in all positions.
Practical tip: Store rods in a dry oven at 250°F to prevent hydrogen cracking. I once used damp 7018 rods on a critical beam, and tiny cracks showed up later—lesson learned, always check moisture.
Gas Metal Arc Welding (GMAW): When Speed Is Key
GMAW, often called MIG, feeds a continuous wire electrode through a gun, with shielding gas flowing out.
The arc melts the wire into the pool, and gas like argon or CO2 keeps air away. It’s semi-automatic, so you control the gun while the machine handles wire feed.
Great for automotive bodywork or fabrication shops needing clean, fast welds on mild steel or aluminum. Use it horizontally or flat for best results.
Tip: Set wire speed to match amperage—too fast causes bird-nesting in the drive rolls. In my shop, we dial it in on test plates to avoid downtime.
Pros: High deposition rates, minimal cleanup. Cons: Sensitive to wind, higher setup cost.
Gas Tungsten Arc Welding (GTAW): For Precision Work
GTAW, or TIG, uses a non-consumable tungsten electrode with separate filler rod and inert gas shield.
The arc is struck by high-frequency start or touch, melting the base while you add filler manually.
Perfect for thin stainless or exotic alloys in aerospace or food-grade piping where quality trumps speed.
Why use it? Precise control over heat input minimizes distortion.
Shop advice: Sharpen your tungsten to a point for DC work; ball it for AC on aluminum. I’ve seen pros ruin jobs with dull tips leading to wandering arcs.
Other Arc Processes Like FCAW and SAW for Specialized Jobs
Flux-cored arc welding (FCAW) is like MIG but with flux in the wire, optional gas. Use it for thick sections in construction—high speed, portable.
Submerged arc welding (SAW) buries the arc under flux for automated, high-volume work like shipbuilding.
When? For repetitive, flat welds on heavy plate.
Tip: In FCAW, watch for slag inclusions; chip thoroughly between passes.
Here’s a quick comparison table:
| Process | Electrode Type | Shielding | Best For | Pros | Cons |
|---|---|---|---|---|---|
| SMAW | Consumable (coated rod) | Flux/slag | Repairs, all positions | Versatile, low cost | Slow, slag removal |
| GMAW | Consumable (wire) | Gas | Production, clean welds | Fast, easy | Wind-sensitive, equipment heavy |
| GTAW | Non-consumable (tungsten) | Gas | Precision, thin metals | High quality | Skill-intensive, slow |
| FCAW | Consumable (flux-cored wire) | Flux/gas | Thick materials, outdoors | Portable, deep penetration | Fumes, spatter |
| SAW | Consumable (wire) | Flux blanket | Automated, heavy industry | High productivity | Limited positions, setup complex |
Choosing the Right Electrode for Your Arc Welding Job
Electrodes are your lifeline in arc welding—they carry current, add filler, and provide shielding. Get it wrong, and your weld fails.
What are they? Rods or wires classified by strength, position, and coating. For example, E6010 is cellulose-coated for deep penetration.
How to choose: Match to base metal—use 7018 for low-hydrogen on high-strength steel.
Diameters range from 1/16″ to 5/32″; smaller for thin work, larger for thick.
Practical tip: For mild steel, start with 1/8″ 6013—forgiving for beginners. I keep a rod chart taped to my welder for quick reference.
Understanding Electrode Diameters and Their Impact
Smaller diameters (3/32″) give finer control but lower deposition. Larger (5/32″) handle higher amps for faster work but risk burn-through on thin stock.
Use 1/8″ for most shop jobs—balances speed and precision.
Tip: Measure your material thickness; electrode diameter should be half or less for root passes.
Amperage Ranges: Getting the Heat Just Right
Amperage controls heat—too low, poor fusion; too high, spatter and distortion.
For 1/8″ 6010: 75-125 amps. 7018: 90-140 amps. Adjust based on position—lower for overhead.
From experience, start at the low end and bump up if the rod sticks. On a Lincoln Idealarc, I fine-tune with the dial while watching the puddle.
Table of common ranges:
| Electrode Type | Diameter | Amperage Range (DC) | Polarity | Typical Use |
|---|---|---|---|---|
| E6010 | 1/8″ | 75-125 | DCEP | Pipe, deep penetration |
| E6013 | 3/32″ | 40-90 | AC/DC | Sheet metal, easy striking |
| E7018 | 1/8″ | 90-140 | DCEP | Structural, low hydrogen |
| E308 | 1/8″ | 80-120 | DCEP | Stainless steel |
| ER70S-6 (MIG wire) | 0.035″ | 100-200 | DCEP | Mild steel, auto body |
Setting Up Your Welder for Optimal Performance
Setup starts with polarity: DCEP (reverse) for most stick work—deeper penetration.
Amperage: Rule of thumb—1 amp per 0.001″ of electrode diameter as starting point.
For US machines like Miller Thunderbolt, plug into 220V for full power.
Tip: Ground clamp close to the joint to minimize resistance. I’ve chased ghost issues from loose clamps more times than I can count.
Joint Preparation: Don’t Skip This Step
Proper prep ensures clean fusion. What is it? Cleaning, beveling, and aligning edges.
How: Grind to bright metal, bevel 30-45° on thick plates for multi-pass.
When: Always on rusty or painted stock.
Step-by-step guide:
- Clamp pieces securely—movement causes cracks.
- Clean with wire brush or grinder.
- Bevel if over 1/4″ thick.
- Tack weld ends to hold alignment.
- Weld in short runs to control heat.
Tip: For butt joints, leave 1/16″ gap for expansion. Forgot this once on a gate repair, and it warped badly.
Filler Metal Compatibility: Matching Materials for Lasting Welds
Filler must match base chemistry to avoid brittleness. For carbon steel, use ER70S; stainless, 308L.
Why? Mismatch causes corrosion or weak spots.
Shop note: Check AWS classifications—E for stick, ER for wire. Store fillers dry to prevent defects.
Common Mistakes That Even Pros Make in Arc Welding
Mistakes happen, but knowing them saves rework.
One biggie: Too long arc length—causes spatter and poor penetration. Fix by shortening to electrode diameter.
Dirty surfaces lead to porosity—always clean.
Wrong amperage: Low sticks rods, high burns holes. Test on scrap.
Beginners often move too fast, leaving undercut. Slow down, weave steadily.
Pros forget rod angle—keep 15-20° drag for flat welds.
Anecdote: I undercut a trailer hitch once rushing; ground it out, refilled—time lost, but stronger after.
How to Fix Bad Welds from Wrong Settings
Porous weld? Grind out, reclean, reweld with dry rod.
Undercut: Fill with lower amp pass.
Cracks: Cut out section, preheat if high carbon, reweld.
Tip: Use dye penetrant to check hidden flaws before final assembly.
Safety Considerations: Staying Safe While Striking Arcs
Safety isn’t optional—arcs produce UV, heat, fumes.
Wear leather gloves, long sleeves, and auto-darkening helmet (shade 10-13).
Ventilate to avoid fume inhalation—use exhaust fans.
Eye protection always; arc flash burns retinas.
Tip: Keep fire extinguisher handy for spatter. Wet gloves shock—dry them.
Common oversight: Welding near flammables—clear 35 feet radius.
Real-World Shop Anecdotes: Lessons from the Floor
In my early days, I arc welded a exhaust manifold with wrong rod—cracked in a week. Switched to compatible filler, lasts years now.
For DIY: Fixing lawnmower frames with SMAW—quick, strong.
Pro jobs: Pipeline repairs demand low-hydrogen rods to pass X-ray.
Tip: Practice vertical ups—gravity pulls puddle, so lower amps, short arcs.
Pros and Cons of Arc Welding in Everyday Use
Pros: Affordable, portable, versatile materials.
Cons: Skill-dependent, slower than some, fumes.
Balances well for most US shops.
Wrapping Up
Arc welding’s simplicity hides its power—once you grasp the arc’s behavior and match settings to your job, your welds hold up under real stress. You’re now equipped to pick the right process, electrode, and amperage without guesswork, cutting down on failures and boosting confidence in the shop. Always preheat high-carbon steels to 300°F before welding—it prevents those sneaky cracks that show up later.
FAQs
What amperage should I use for 1/8-inch 7018 rods?
Start at 90-110 amps for flat positions, bump to 120-140 for vertical. Test on scrap—rod should burn smoothly without sticking.
Why is my arc welding producing too much spatter?
Likely too long arc or high amps. Shorten to 1/8 inch, drop amps 10-20. Clean metal and check polarity—DCEP for most.
Can I arc weld aluminum with a basic stick welder?
Not easily—stick is tough on aluminum due to oxide. Switch to TIG or MIG with argon for clean results. If stuck, use specialty AC rods but expect challenges.
How do I prevent porosity in my arc welds?
Clean surfaces thoroughly, use dry rods, and maintain proper shielding. For SMAW, store rods in an oven; for MIG, check gas flow at 20-30 CFH.
What’s the best arc welding process for beginners?
Start with SMAW—forgiving and cheap. Practice on mild steel scraps to build arc control before moving to MIG for speed.