A New Way to Laser Engrave Glass

How would you like to laser-engrave a drawing on a sheet of glass that you can view against a light background? Not the frosted look, but clean black lines like an ink drawing! I found a new and simple way to do this on a CO2 laser.

With this technique you can make unique window hangings, embellish framed pictures, build layered art scenes, add descriptions and embellishments to display cases, create cool moiré patterns, illuminated signs, and many more things. The technique also works well on ceramic tiles.

All you need is:

1. A sheet of glass
2. White glue (e.g. Elmer’s School Glue)
3. Titanium dioxide powder TiO2
4. Food coloring (if you want to do tiles)
5. mixing container, and
6. Access to a CO2 Laser

The technique may work with a diode laser, I don’t know. If you try this successfully on a diode laser please share it here with the Instructables community.

The process works by coating the glass with a layer of titanium dioxide before engraving it with a laser cutter. The laser will score the glass; and melt and fuse the TiO2 into the resulting groove. The fused TiO2 turns black. After washing off the coating you have a sketch with lines that are permanent and black; and stand out well against the transparent (or frosted) glass.

Mix up the following:

2 parts water

1 part school glue or white (interior) glue

2 parts TiO2 powder

Mix well to be sure all ingredients are evenly distributed. The mixture will keep for some time in a closed container for later use.

With a soft paint brush apply an even coat of the TiO2 mixture to the area of the glass you want to engrave. Try to minimize brush lines. Let the coating dry completely. When dry you should be able to lightly brush your finger over it without picking up any residue. If desired apply a second coat, brushing perpendicular to the first application. Let it dry again. The purpose of the glue in the mixture is to bind the TiO2 powder so that the air assist of the laser cutter doesn’t blow it away during the engraving.

Now it’s time to laser engrave. Here I use the ‘score’ setting of my laser cutter. This function is used when you don’t want to cut all the way through the work piece. The score function requires a vector file, or line type file and is most useful when emphasizing the outline of text or an object. Scoring is very similar to cutting, but at less powerful settings. It is used to mark the work piece, but not cut all the way through it. You will have to experiment with your specific laser cutter and software to find the optimal settings for your system. Settings for my 40W CO2 laser are: Heat 50%, Speed 50%, Depth 60%.

You may wish to secure the glass to the laser cutter bed with tape to prevent it from shifting. The glass is very slippery, and even minor vibrations of your machine may shift the glass during engraving, ruining the job. I found out the hard way.

For me the technique works really well, but only with vector files (e.g. svg). Raster images like jpeg or png files do not work; at best I get faint and blotchy results. Your mileage may vary; let me know. Vector files do scale better and perform faster. The cat image shown was Designed by Freepik (www.freepik.com). There are various ways to convert a raster image to a vector file, but that’s beyond the scope here.

After lasering remove the glass sheet from the laser cutter and rinse/wipe the coating off with warm water. Use a toothbrush to remove all coating residues from the glass and the engraved grooves. Clean and dry, you are done! Admire your work against a light background.

The same technique also works well on ceramic tiles. You may wish to add a few drops of food coloring (I used yellow) to the coating mixture to better see if you covered the tile evenly. White tiles with engraved artwork look great; and colored or slightly textured tiles can also be engraved successfully. You may have to tweak the laser cutter settings when working with ceramic tiles. As the TiO2 is fused into the tile the artwork should last well in an outside setting.

I also tried the technique on acrylic, and it does not work. The TiO2 does not fuse to the plastic. The same is true for wood. So stick with glass and ceramic tiles!

I engraved some circular Moiré patterns on glass sheets. Moiré pattern interference occurs when two identical or nearly identical patterns with transparent gaps are overlayed and displaced or rotated respective to each other. The effect can be striking. It makes for interesting artwork. If you mount two moiré glass sheets with a space between them then the pattern moves as you view the patterns from different angles. Enjoy and experiment!