What's inside
- What CO2 Lasers Can Actually Cut (and Why the Limits Exist)
- Power Levels: What Each Tier Buys You
- Assist Gas: The Cost Nobody Puts in the Brochure
- Cooling and Duty Cycle Realities
- Decision Matrix: CO2 vs. Fiber for Your Situation
- Ownership Realities: What Wears First
- What to Look For in a Metal-Capable CO2 Machine
- FAQ
- Related Guides
- What CO2 Lasers Can Actually Cut (and Why the Limits Exist)
- Power Levels: What Each Tier Buys You
- Assist Gas: The Cost Nobody Puts in the Brochure
- Cooling and Duty Cycle Realities
- Decision Matrix: CO2 vs. Fiber for Your Situation
- Ownership Realities: What Wears First
- What to Look For in a Metal-Capable CO2 Machine
- FAQ
- Related Guides
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A CO2 laser cut metal machine can cut metal — but only thin sheet, only with enough power and the right assist gas, and almost always slower and with more limitations than a comparably priced fiber laser. If your work is mostly mild steel under about 3mm, stainless under about 2mm, or mixed metal-and-nonmetal jobs, a high-wattage CO2 machine can earn its place. If you plan to cut aluminum, brass, copper, or anything over 4–5mm regularly, buy a fiber laser instead.
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What we cover
- What CO2 Lasers Can Actually Cut (and Why the Limits Exist)
- Power Levels: What Each Tier Buys You
- Assist Gas: The Cost Nobody Puts in the Brochure
- Cooling and Duty Cycle Realities
- Decision Matrix: CO2 vs. Fiber for Your Situation
- Ownership Realities: What Wears First
- What to Look For in a Metal-Capable CO2 Machine
- FAQ
- Related Guides
What CO2 Lasers Can Actually Cut (and Why the Limits Exist)
A CO2 laser produces a 10.6μm wavelength beam, which metals reflect strongly rather than absorb. That’s the core of every limitation in CO2 laser metal cutting. Wood, acrylic, and leather absorb this wavelength eagerly; a sheet of steel throws most of it back. Fiber lasers emit at roughly 1μm, which metals absorb far more efficiently — this is why a 1kW fiber laser can out-cut a 150W CO2 on steel at a fraction of the power draw.
Practical cutting envelope for a CO2 laser for cutting metal, assuming proper assist gas and a metal-capable machine:
- Mild steel: up to ~3mm at 150W, ~4–6mm at 300–400W, with oxygen assist
- Stainless steel: up to ~2mm at 150W, ~3–4mm at 300W+, with nitrogen assist for a clean, oxide-free edge
- Aluminum: technically possible at very thin gauges (~1mm) at high power, but reflective back-burn risk makes it a poor candidate — avoid on machines under 300W
- Copper and brass: do not attempt on a CO2 machine; reflectivity can destroy the optics
- Galvanized steel: cuttable, but zinc fumes require serious extraction — treat as a ventilation problem first
Power Levels: What Each Tier Buys You
| CO2 Tube Power | Mild Steel Max (O2 assist) | Stainless Max (N2 assist) | Typical Machine Cost | Realistic Use Case |
|---|---|---|---|---|
| 60–80W | ~0.5mm (barely) | Not recommended | $2,000–$5,000 | Engraving coated metals only; not a cutting tool |
| 100–130W | ~1–1.5mm | ~1mm | $4,000–$9,000 | Occasional thin brackets, shims, decorative steel |
| 150–180W | ~2–3mm | ~1.5–2mm | $8,000–$15,000 | Mixed shops cutting acrylic + thin steel regularly |
| 300–500W (slab/diffusion-cooled) | ~4–6mm | ~3–4mm | $20,000–$60,000 | Dedicated thin-sheet production; still slower than fiber |
For comparison, a 1–1.5kW fiber laser in the $15,000–$30,000 range cuts 3mm mild steel several times faster and handles up to ~10mm — which is why the crossover point matters so much in your purchase decision.
Assist Gas: The Cost Nobody Puts in the Brochure
CO2 laser cutting metal without assist gas doesn’t work — the gas blows molten material out of the kerf and either adds energy (oxygen) or protects the edge (nitrogen).
- Oxygen for mild steel: exothermic reaction adds cutting power, leaves a dark oxide edge you’ll need to clean before welding or painting. Consumption is modest; small cylinders last well.
- Nitrogen for stainless and aluminum: high-pressure, high-volume consumption. A stainless job can burn through a cylinder surprisingly fast — budget roughly $30–$80 in gas per cylinder fill depending on region, and expect nitrogen to become your largest ongoing consumable at volume.
- Compressed air is a cheap compromise for thin stainless where edge color doesn’t matter, but you need a clean, dry, oil-free supply with adequate pressure (typically 10–16 bar for nitrogen-equivalent results).
Machines marketed for metal cutting must have a gas delivery system rated for these pressures — many hobby-tier CO2 beds only deliver low-pressure air for acrylic work. Check the gas spec before anything else.
Cooling and Duty Cycle Realities
Glass-tube CO2 lasers at 100W+ need a real chiller, not the bundled aquarium pump. A CW-5200-class refrigerated chiller is the practical minimum for a 130–150W tube doing sustained cutting; undersized cooling is the number-one cause of premature tube death. Metal cutting also runs the tube at high continuous output — harder on it than intermittent acrylic work. Expect a quality glass tube to last roughly 2,000–4,000 hours at conservative power settings; RF-excited metal tubes last far longer but cost several times more to replace.
Decision Matrix: CO2 vs. Fiber for Your Situation
| Your Situation | Right Choice | Why |
|---|---|---|
| Cut mostly wood/acrylic, occasional steel under 2mm | 150W+ CO2 | One machine covers both; fiber can’t cut organics |
| Metal is the primary product, any thickness | Fiber 1kW+ | 3–10x faster on steel; cuts copper/brass CO2 can’t touch |
| Budget under $10k, need both metal and signs/engraving | 130–150W CO2 | Entry fiber machines that cut well start higher |
| Stainless work where edge finish matters | Fiber (or accept N2 gas costs on 300W+ CO2) | Fiber gives brighter edges at lower operating cost |
| Limited space, garage shop | CO2 desktop (sub-2mm metal only) | Fiber needs more guarding; enclosed fiber options exist but cost more |
Ownership Realities: What Wears First
- Focus lens and mirrors: metal cutting splashes more contamination back at the optics than wood work. Expect lens replacement every few hundred hours of metal cutting; keep spares on hand.
- Nozzle: the single most important cutting variable. Damaged or misaligned nozzles ruin kerf quality immediately. Consumable — buy in packs.
- Tube: derate it (run at 80% of rated power) and keep coolant at 18–22°C to maximize life.
- Slat bed: metal cutting fuses dross onto support slats; they need regular cleaning or replacement, unlike honeycomb beds used for wood.
- Common mistake: buying a 100W machine expecting “laser cut metal” performance. At that tier, you’re doing a slow, marginal 1mm cut at best — the machine is an engraver with a party trick.
What to Look For in a Metal-Capable CO2 Machine
Brands with genuine metal-cutting CO2 offerings in 2026 include Omtech (their MF-series hybrid heads), Thunder Laser, Boss Laser (LS and FC lines), and Epilog’s higher-power Fusion models. At the industrial slab-laser end, Kern and Trotec offer 400W+ systems. Whatever the brand, verify: a cutting head rated for high-pressure gas, an autofocus or capacitive height sensor (critical because metal warps during cutting), a refrigerated chiller included or budgeted, and a stated mild-steel thickness rating — not just “cuts metal” in the marketing copy.
FAQ
Can a 100W CO2 laser cut metal?
Barely — roughly 1mm mild steel with oxygen assist and careful focus. It’s viable for occasional thin work, not for anything you’d call production.
Is CO2 or fiber cheaper to run for metal?
Fiber, decisively. No mirrors to align, no tube replacements, lower electricity per cut, and faster throughput. CO2 only wins when you also need to cut nonmetals on the same machine.
Do I need ventilation beyond assist gas?
Yes — metal fumes (especially galvanized zinc and stainless hexavalent chromium compounds) require dedicated extraction and filtration, not just a window fan.
