How to Engrave on Glass?

Why Engrave on Glass?

Glass engraving with a diode laser produces a beautiful etched, frosted effect that catches light elegantly, adding a touch of sophistication to your projects. Diode laser machines are affordable but their beams are not naturally absorbed directly by the glass. So, base coating is applied to make engraving work. By applying a temporary coating like tempera paint, laser marking paper or a layer of marker pen, the laser can effectively "bite" into the glass without slipping or reflecting excessively, resulting in sharp details. It's ideal for creating illuminated pieces when combined with LED lights or for standalone decorative items.

Materials Needed

A.Materials:

• Glass item (e.g., wine glass, bottle; start with inexpensive options).
• Absorbent coating: Tempera paint, masking tape, or black marker (dark colors optimize laser absorption).
• Optional: Black cardstock (enhances contrast for flat glass).

B.Tools:

• Diode laser engraver (e.g., 20W NEJE Max 4).
• Software: LightBurn or NEJE Control Software.
• Rotary attachment (optional, for curved surfaces).

**Note:** Always ensure your workspace is ventilated, as engraving can produce minimal smoke. Avoid engraving leaded crystal or tempered glass, as they may shatter under heat!!!!

Step-by-Step Instructions

Step 1: Prepare Your Glass

1. Clean the glass thoroughly with soap and water to remove any oils, fingerprints. Then dry it completely with a lint-free cloth.
2. .Apply two thin layers of the paint mixture (make sure that the glass is not visible on the surface) to the area you want to engrave. Let the first layer dry before adding the second. But if you use laser marking paper, you just need to put it on.
3. If working with flat glass, place black cardstock underneath for better laser focus and to prevent reflections. Secure everything with tape to avoid movement.

**Tip:** For curved items like cup, please use a rotary attachment to rotate the piece evenly during engraving.

Step 2: Set Up the Design and Software

1. Secure glass on the engraver bed (attach rotary if needed).
2. Import designs to software (vector for sharp lines; bitmap for details). Recommended Settings: 20W laser: Speed 9000 mm/min, Power 80%, 1 pass.10W laser: Speed 6000 mm/min, Power 70%, 1 pass.

**Tip:** Start low and adjust based on your machine—overpowering can cause cracking.

Step 3: Perform the Laser Engraving

1. Double-check your setup, put on safety glasses, and start the engraving process. 
2. The laser will burn through the paint coating, etching the glass underneath and creating a frosted texture.

**Warning:** If engraving curved glass, ensure the rotary speed matches your software settings to prevent distortion.(https://neje.wiki/doku.php?id=rotary_r6)

Step 4: Clean and Admire your work! 

1. Once complete, cool glass for 5 minutes. Gently remove any remaining paint with a damp cloth or under running water—the etched design will remain intact. 
2. If your project includes lighting, insert the engraved glass into an LED base and connect it to power. The frosted design will glow beautifully when illuminated. 

Additional Tips for Success

• Test first: Practice on scrap glass to adjust settings.
• Enhance designs: Fill engravings with metallic rubs or paint after cleaning.