How to Engrave Glass, Slate, and Stone with a Laser Using Marking Compounds

Introduction

Laser engraving on bare glass or stone with a diode or CO2 laser produces poor results — the beam passes through or reflects off the hard surface without leaving a lasting mark. Laser marking compounds solve this problem by creating a heat-reactive layer that bonds permanently to the surface when hit by the laser. Products like CerMark, LaserBond, and dry molybdenum lube spray turn an ordinary laser into a tool for creating permanent, high-contrast engravings on glass, ceramic tile, slate, stainless steel, aluminum, and other hard surfaces.

Marking Compounds

CerMark LMM-6000 (Aerosol Spray)

• Best for: Metals, glass, ceramic
• Application: Spray can, light even coat
• Finish: Matte black mark
• Cost: ~$50-70 per can

Dry Molybdenum Lube Spray (Budget Alternative)

• Best for: Glass, ceramic, stainless steel
• Cost: ~$8 at auto parts stores
• Finish: Dark gray/black mark
• Less durable than CerMark but works well for decorative items

LaserBond 100 (Liquid Brush-On)

• Best for: Detailed work, small areas
• Application: Brush or dab on
• Finish: Jet black mark

Step 1: Surface Preparation

1. Clean the surface thoroughly with isopropyl alcohol
2. Remove all oils, fingerprints, dust, and residues
3. For glass: ensure it is room temperature
4. For metal: light sanding with 400 grit improves adhesion
5. Handle with clean gloves

Step 2: Apply the Compound

1. Shake the can vigorously for 2 minutes
2. Hold can 6-8 inches from surface
3. Apply a thin, even coat — just enough to cover
4. Should look like a light dusting, not a painted surface
5. Let dry completely (CerMark: 5-10 min, dry moly: 2-3 min)

Step 3: Laser Settings

Glass (CO2 40W)

• Speed: 100-150mm/s
• Power: 30-40%
• Passes: 1-2

Slate and Stone (CO2 40W)

• Speed: 200-300mm/s
• Power: 40-50%
• Passes: 1

Stainless Steel (Fiber 20W)

• Speed: 500-800mm/s
• Power: 80-100%
• Passes: 1

Ceramic Tile (CO2 40W)

• Speed: 150-250mm/s
• Power: 35-45%
• Passes: 1-2

Step 4: Engrave and Clean

1. Position item on the laser bed
2. Use rotary attachment for cylindrical items
3. Focus on the coated surface
4. Run a frame/outline at low power to verify position
5. Run the engraving job
6. Let the item cool completely
7. Rinse under warm water and scrub with paper towel
8. Clean with isopropyl alcohol for a spotless finish

Troubleshooting

• Faint mark: Apply slightly heavier coat, increase power, or reduce speed
• Mark washes off: Not enough power to fuse — increase power
• Uneven mark: Uneven compound application or dirty lens

Pro Tips

• Always do a test mark on the back or bottom of the item first
• Rotate wine glasses slowly in a rotary attachment
• For dark slate: try engraving without compound — laser ablates dark surface revealing light stone
• Masking paper under glass prevents back-reflection damage to the laser
• Dry moly spray works surprisingly well and costs 1/10th of CerMark

Conclusion

Marking compounds transform a standard laser engraver into a tool for permanent, professional-grade marking on glass, stone, ceramic, and metal. CerMark is the gold standard for durability, but dry molybdenum spray offers excellent results at a fraction of the cost for decorative work. The keys are clean surface prep, a thin even coat, proper laser settings, and thorough cleaning after engraving.