Engraving Glass with the Ray5 20W — Wet Paper Method
ray5glassengravingwet paper
Clear glass normally reflects diode laser wavelengths. The wet paper method solves this and produces excellent results.
Why Glass is Difficult for Diode Lasers
The Ray5 produces ~450nm blue laser light. Clear glass is transparent to this wavelength — the laser passes straight through without effect.
Solution: Cover the glass with wet paper. The paper absorbs the laser energy, transfers heat to the glass surface, and ablates the glass underneath to create a frosted mark.
Materials Needed
- Flat glass piece (window glass, photo frame glass, glass tile)
- Paper towels or white tissue paper
- Water spray bottle
The Process
- Clean glass with IPA — no fingerprints
- Wet a sheet of paper towel — thoroughly damp but not dripping
- Lay it flat on the glass — no bubbles, smooth contact
- Ensure paper is perfectly flat — any lift causes uneven engraving
- Focus the laser on the paper surface (not the glass below)
- Run the engrave job
- Peel off paper while still slightly damp
- Wipe glass clean with damp cloth
Settings
| Speed | Power | Result |
|---|---|---|
| 2000 mm/min | 50% | Light frosted mark |
| 1500 mm/min | 65% | Standard |
| 800 mm/min | 80% | Deep frosted |
Troubleshooting
| Problem | Cause | Fix |
|---|---|---|
| Uneven engraving | Paper bubbles | Flatten paper better |
| No mark at all | Paper too wet/thick | Use thinner paper, less water |
| Glass cracking | Too much power/slow | Reduce power |
Alternative: Black Spray Paint Method
- Spray black paint on glass
- Engrave — laser removes the paint and marks the glass
- Clean remaining paint with isopropyl
Results similar to wet paper but with more control over power settings.
Works Best On
- Flat glass only — curved surfaces cause focusing issues
- Tempered glass can shatter from thermal stress — use only annealed glass