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Metal Marking Guide: Using Thermal Additives

Can a CO2 laser mark metal? The answer is yes, provided you use the correct thermal marking additive. This guide explains how to achieve permanent, high-contrast marks on metallic surfaces with your Neon.

Do I Need an Additive?

It depends on the surface finish of the metal:

  • Raw Metals (Steel, Aluminum, Brass): Yes, an additive is mandatory. CO2 laser beams are normally reflected by shiny metal surfaces. The additive absorbs the laser energy and thermally bonds to the metal, creating a permanent black mark.
  • Anodized or Painted Metals: No additive is required. In these cases, the laser removes or bleaches the coating/paint to reveal the mark.

Where to Find It

These additives are commonly sold as sprays, pastes, or liquids under brands like Cermark or Brilliance. They are widely available through specialized laser supply stores and major online retailers.

Step-by-Step: Marking Raw Metal

Step 1: Surface Preparation

Ensure the metal surface is completely clean, dry, and free of any oils or fingerprints. Use isopropyl alcohol for the best results.

Step 2: Application

  • Liquid/Paste: Apply a thin, even layer using a soft brush over the area to be engraved.
  • Spray: Shake the can well and spray at a distance of approximately 30cm.
  • Goal: You want a consistent, "frosted" look. A layer that is too thick will actually shield the metal and prevent a good bond.

Step 3: Drying

The additive must be bone-dry before firing the laser. You can let it air dry or speed up the process using a heat gun or a common hair dryer.

Marking metal requires high energy density. Use the following starting points:

  • Power: 100% (Always)
  • Resolution: High (Check the settings in the top-right corner of Neon Studio)
  • Speed: Start at 50.
    • If the mark wipes off easily after washing, reduce the speed (down to 10) to increase the "cook" time.
    • If it still doesn't mark at Speed 10, that specific metal alloy may not be compatible with CO2 thermal bonding.

Finalizing the Piece

Once the engraving is complete, simply wash the metal with plain water or a damp cloth. The excess un-laserable powder will wash away, leaving only your permanent design.

Pro Tip

Marking metal is an "all-or-nothing" process. If you find the mark is inconsistent, check your focus carefully. Even a 1mm deviation in focus can be the difference between a perfect mark and no mark at all on stainless steel.

Having trouble with a specific alloy? Some coatings on "stainless" steel can interfere with the bonding process. Contact Neon Laser Support if you need help troubleshooting a difficult metal substrate.