The range of materials suitable for even the cheapest laser cutter is part of what makes them such versatile and desirable tools. As long as you temper your expectations, there’s plenty of material to cut with your 40 watt CO2 laser or at least engrave—just not glass; that’s a tough one.
Or is it? According to [rschoenm], all it takes to engrave glass is a special coating. The recipe is easy: two parts white PVA glue, one part water, and two parts powdered titanium dioxide. The TiO2 is the important part; it changes color when heated by the laser, forming a deep black line that adheres to the surface of the glass. The glue is just there as a binder to keep the TiO2 from being blasted away by the air assist, and the water thins out the goop for easy spreading with a paintbrush. Apply one or two coats, let it dry, and blast away. Vector files work better than raster files, and you’ll probably have to play with settings to get optimal results.
With plain float glass, [rschoenm] gets really nice results. He also tried ceramic tile and achieved similar results, although he says he had to add a drop or two of food coloring to the coating so he could see it against the white tile surface. Acrylic didn’t work, but there are other methods to do that.
Thanks to [AbraKadabra] for the tip.
“the TiO2 is the important part; it changes color when heated by the laser”
So sunscreen or toothpaste might work too?
emulsion paint too.
Not entirely keen on flushing nanoparticle TiO2 without knowing more about the potential environmental impact but I guess this application would be a very minor net contributor
This is a well-known technique for laser etching metal, although this is the first time I’ve seen it used with glass.
You can use molybdenum spray lubricant, available at the local auto parts store, to laser etch metal. The molybdenum sinters into the metal and leaves behind a nice gray “mark”. Use this to put your logo on metal parts that you make.
Spray lubricant might work on glass as well. You might also try titanium spray paint.
A potential problem with experimenting on glass is that the heat of the laser tends to crack the glass. If this happens, try using less power and/or faster speeds.
the spray lube trick works on stainless steel, and isn’t a proper etch or sinter; the laser heat causes a chemical reaction involving the chromium in the stainless, and the sulfur in the molybdenum disulfide. I forget most of the details, but I don’t believe it should work on glass.
For straight etching of glass with laser, I’ve used a layer of damp newsprint, though I haven’t a clue where you would find that nowadays. Raster mode only.
Cool! Now, print over it
Works really well. I did this couple years ago, for more info: norton white tile methode
He tested many sprays and different laser settings etc.
Titanium dioxide is an n-type semiconductor. Instructions unclear, my window now runs windows.
I’m all for the nice black contrast, but you can absolutely engrave glass without the special coating on a CO2 laser. . A wet piece of newsprint over the material to reduce excess chipping, and the laser leaves very nice marks where it fractured small chips free under the sudden heat. Certain kinds of tempered glass don’t work neatly with this, but I’ve run hundreds of bottles and cups and things like that.
To the best of my knowledge, this doesn’t work with a diode laser, but the article specifically mentions he has a CO2 machine.
The TiO2 provides the black marking in the laser engraved line. Without the TiO2 the line would be much less visible, especially when viewed against a light background. Closeup images of the lines are here: https://www.reddit.com/r/Laserengraving/comments/1i87rzj/closeup_of_co2_lasercut_groove_in_glass_with_tio2/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
I didn’t know about the wet newsprint trick to reduce chipping; will have to try that. Thanks!
I was too lazy to google this, mainly because it’s one of those things I’ve never particularly wanted to try but I had it in my memory somewhere that a CO2 laser would etch glass.
The TiO2 is a neat trick though, I suspect it embeds itself into the glass with the heat of the laser…
Should probably also work with metals. This is similar than engraving sprach you can buy. Although those or often based on molybdenum compounds.
Probably cheaper than using laser etch film (e.g. Folex), albeit likely to be less consistent. Likely not a problem for basic vector art as in the OP, but may not be so great with raster etches that have varying tones.
Derp, not Folex, that’s a different process! Anyway, “laser marking paper” should turn up plenty of sources for suitable films.
Using glass frit (the finer the better) may also work when combined with a binder/sticking agent. I’ve tried it without and (if you turn off/away the air assist) it can melt/sinter the colour to the enamel of a glazed tile.
But the price of enameled tile itself is so low this technique only makes sense to customise tiles.
Perhaps a modern version of stained glass windows?
I just saw a post on the glowforge forums where somebody is laser “firing” ceramic glazes. Looks amazing. I wonder if they would work here?
Acrylics absolutely DO work. I use white acrylic craft paint to get black markings on glass and tile and I use black acrylic craft paint to get white markings on glass. Been doing that for several years now with absolutely beautiful; results on both a 5w as well as a 20w.
Are you using a diode laser? This was done with a CO2 laser.
I just use acryilic spray paint, black, under my diode laser and it works great. Afterwards I also put on some glass etching paste and rinse everything off with hot water, the paint falls right off so no use for chemicals.
No black lines though.