Fiber vs CO2 for Metal: Bare vs Coated Marking

If your product is metal, "fiber or CO2?" is not really a choice, it is a physics test most sellers fail expensively. A fiber laser fires at 1064 nm, a wavelength bare metal absorbs; a CO2 fires at 10,600 nm, which bare metal reflects. That one fact means a fiber marks raw stainless, brass, aluminum, and titanium directly, while a CO2 can only mark metal that has been coated or sprayed first. Buy the wrong one and you will spend your margin on coatings you did not need, or discover your machine cannot touch your product at all.

We score by class, standardizing published specs against owner reports and community results rather than operating a test lab. Here is the metal decision made simple.

The quick answer

• Choose a fiber laser if you mark or engrave bare metal: stainless tumblers, brass tags, aluminum, titanium. It hits raw metal directly, deeply, and fast.
• A CO2 can only mark coated metal: anodized aluminum, powder-coated blanks, or bare metal prepped with a marking spray, an extra step and cost per piece.

For a metal business, fiber is the honest tool. See a fiber MOPA; for coated-metal-plus-everything-else, a 55W CO2.

Fiber vs CO2 on metal at a glance

Specs current as of mid-2026.

Why fiber owns bare metal

At 1064 nm the beam is absorbed by raw metal, so a fiber laser does what no CO2 or diode can: mark bare stainless steel black, anneal a permanent oxide mark, or engrave measurable depth into brass and aluminum with no coating and no spray. A tray of stainless keychains or steel tumblers goes straight under the beam. Galvo fiber machines are also fast, marking speeds run into the thousands of mm/s, so metal batches move quickly. If bare metal is your product, this is the class.

Why CO2 needs a coating

A CO2's infrared is reflected by bare metal, so it cannot mark raw steel at all. It can mark metal that carries something the beam can grab: anodized aluminum (the beam ablates the dye for a bright mark with no material removed), powder-coated blanks, or bare metal painted with a marking compound that fuses under heat. That works, but every piece needs the coating step, which adds cost and time. The CO2's real strength is everywhere else, wood, acrylic, glass, leather, so it is the better machine for a shop whose metal work is occasional and coated.

MOPA: the color upgrade

Within fiber, a MOPA source adds a tunable pulse that unlocks full color on stainless and titanium and cleaner marks on anodized aluminum. If color metal is a selling point, a MOPA such as the ComMarker B4 is the tool, and we weigh dual-source versus MOPA in our F1 Ultra vs ComMarker B6 comparison. A standard fiber is plenty for black and annealed marks; MOPA is for color and finish control.

Materials and safety

Fiber's metal menu is bare and coated stainless, brass, aluminum, and titanium; CO2's is coated metal plus the full non-metal range. The safety rules apply to both. Never put PVC, vinyl, or any chlorinated plastic under either beam, because chlorine gas destroys lungs and optics. Metal marking also throws fine particulate you should not breathe, so run extraction and wavelength-rated eye protection, keep fire suppression nearby, and never leave a job running unattended. Fiber's speed means a mistake happens fast; prove settings on scrap of the exact alloy first, and pull starting points from our settings calculator.

Field size and batch size

The two classes also differ in how much you mark at once. A galvo fiber has a small, fixed marking field, often about a hand's width, so large pieces must be tiled or run with a larger lens, but small items batch fast under its high speed. A gantry CO2 has a big flat bed, so it engraves large coated panels or many pieces in a single pass, just more slowly on metal because it is only marking a coating rather than biting into the metal itself. For rows of small metal blanks the fiber's speed wins outright; for the occasional large coated-metal sign, the CO2's bed is the more practical tool.

Learning curve

Fiber and CO2 ask different things of you. Fiber settings revolve around power, speed, frequency, and passes, and dialing color on a MOPA is its own craft that rewards patient test grids on the exact alloy. CO2 metal marking is mostly about the coating: lay down an even marking spray or start with a quality anodized blank and the beam does the rest. Neither path is hard, but a metal-first seller will invest more time learning fiber parameters, while a mixed shop treats coated-metal marking as simply one more CO2 material among many.

The business math

Metal marking is high-margin when the tool fits. Model laser-marked stainless pet tags at $12 each: a blank costs under a dollar, a fiber marks it in seconds with no coating, and you net around $10 a tag, so a fiber pays for itself in a few hundred pieces. Try the same product on a CO2 and every tag needs a marking spray or an anodized blank first, eating both time and margin on every unit. If metal is more than an occasional add-on, the fiber's higher sticker is cheaper per finished piece. Anodized blanks like aluminum cards are the exception a CO2 can mark cleanly.

Which one for metal

• Bare-metal seller (tumblers, tags, tools) wants a fiber, MOPA if you want color.
• Mixed shop where metal is occasional and coated is better served by a CO2 doing double duty.

See the metal field in our best fiber laser roundup, the CO2 options in best CO2 laser, and all our buying guides.