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Choosing a MIG Welder for Expanded Metal
Expanded metal panels are easy to weld badly. The raised strands and open spaces create thin edges, uneven contact, and plenty of opportunities to blow holes through the material. A welder that performs well on 1/4-inch plate may be frustrating on 18- or 20-gauge expanded metal.
For most repairs, guards, brackets, cages, and small fabrication projects, the best choice is a 120- or 240-volt MIG welder with stable low-amperage control. You want a machine that can run short-circuit MIG smoothly around 30 to 90 amps, accept .023- or .030-inch solid wire, and make small tack welds without sticking the wire every few seconds.
A basic 120-volt welder is fine for light expanded metal. A 240-volt machine is the better long-term purchase if you also weld frames, angle iron, tubing, or heavier mounting tabs.
Best Welder Types for the Job
| Welder type | Best use | Main advantage | Main drawback |
|---|---|---|---|
| 120V MIG | Light panels, repairs, small frames | Low cost and easy setup | Limited duty cycle and penetration |
| 240V MIG | Regular fabrication and mixed material thicknesses | More stable arc and output reserve | Higher price and needs a suitable circuit |
| Multi-process MIG/TIG/stick | One machine for varied metalwork | Versatility | Often costs more without improving basic MIG performance |
| Flux-core welder | Outdoor work or dirty steel | Works without shielding gas | More spatter and cleanup on thin panels |
For a first machine, compare 120V MIG welders with gas and flux-core capability if you mainly work on thin steel. They are inexpensive, portable, and adequate for many expanded-metal projects.
Shielded solid-wire MIG is usually the cleanest option. Use 75% argon and 25% carbon dioxide when the panel is reasonably clean and you are working indoors. Flux core has a place outdoors or on rusty steel, but its hotter, less forgiving arc can burn through fine strands more readily.
Features That Matter More Than Marketing
Low-end control: This is the most important specification. A machine that starts at 20 or 30 amps is more useful here than one advertising a high maximum amperage. Expanded metal often has strands equivalent to roughly 18- to 14-gauge material, although the surrounding sheet and strand geometry vary by product.
Wire size: .023-inch solid wire gives better control on thin steel. .030-inch wire is a good general-purpose choice for panels attached to heavier frames. Avoid starting with .035-inch wire unless the expanded metal is substantial and you are welding to thick structural steel.
Inductance or arc-control adjustment: This helps tune the arc from harsh and digging to softer and more fluid. It is useful, but not essential on a budget machine. A stable fixed-voltage MIG arc is more valuable than a long menu of digital settings.
Gas solenoid and regulator: If you intend to use solid wire, make sure the machine includes or supports a real shielding-gas connection. A small disposable cylinder is convenient but expensive to refill. A standard cylinder and regulator cost more initially and are cheaper for repeated work.
Duty cycle: Expanded metal is usually welded with short tacks, so you rarely need an extreme duty cycle. A rating around 20% at the machine’s maximum output is acceptable for occasional work. A 30% to 40% rating is more comfortable for production-style frames.
MIG Welder Recommendations by User
Occasional DIY user: A compact 120V MIG/flux-core machine is enough for a kennel panel, vent guard, garden screen, or small equipment shield. The cheaper option is fine when the material is thin, the welds are short, and you are not relying on the welds for a major structural load. Look for compact 120V MIG welders that accept .023-inch wire.
Regular fabricator: A 240V MIG machine with a smooth voltage range is a better fit when you build frames from square tubing and then attach expanded metal. It gives you more reserve for the frame without forcing you to run the panel at excessive heat. A machine with separate voltage and wire-speed controls is preferable to a small unit with only a few preset positions.
Outdoor or dirty-steel work: Choose a MIG machine that runs gas-shielded MIG and flux core. Flux core is useful when wind makes gas shielding unreliable, but clean the slag thoroughly before inspecting the weld. For expanded metal, gas MIG should remain your normal setup when conditions allow.
Starting Settings and Welding Technique
For clean mild-steel expanded metal, start with .023-inch solid wire, 75/25 gas, about 15 to 20 cubic feet per hour of gas flow, and a short stickout of approximately 3/8 inch. On 18- to 20-gauge material, begin near 35 to 55 amps. On heavier 14- to 16-gauge strands, start around 55 to 85 amps. These are starting points, not universal settings; test on a scrap piece made from the same material.
Use short 1/4- to 1/2-inch tacks rather than a continuous bead. Let the metal cool for several seconds between tacks, and move around the panel so heat does not accumulate in one area. A continuous bead can warp the panel, enlarge the openings, or produce a row of burn-through holes.
Keep the gun angle close to 10 to 15 degrees and use a slight travel motion. Do not weave. The goal is to fuse the expanded-metal strand to the frame, not to fill the open diamond. When joining to tubing or angle, aim the arc at the thicker frame edge for a moment, then wash onto the strand.
Common Failures and How to Avoid Them
Burn-through: This happens when the arc stays in one place too long or the voltage is too high. Reduce heat, increase travel speed, and use staggered tacks. A copper backing bar can absorb heat and support a thin edge if the joint allows it.
Cold lap: A weld that sits on top without bonding usually comes from dirty steel, excessive travel speed, or aiming only at the thin strand. Grind off paint, oil, and mill scale, and direct some arc energy into the thicker frame.
Panel distortion: Clamp the panel flat, tack at opposite corners, then add intermediate tacks. Do not assume a panel will remain straight just because each individual weld is small.
Porosity and spatter: Check for wind, a blocked gas nozzle, contaminated steel, or an incorrect gas flow rate. Excessive gas flow can also disturb shielding, so turning the regulator up is not always the cure.
Finally, inspect the joint from both sides where possible. Expanded metal is often used as a barrier rather than a structural member, but its attachment points can still carry impact and vibration. Wear a properly rated helmet, gloves, and nonflammable clothing, and remove coatings before welding; galvanized or painted panels can produce hazardous fumes.