Trying to engrave glass cups

[MHN (Miel)]

Hi! I’ve been trying to engrave glass cups for several days, but the result keeps coming out rough or sandy. Does anyone have any recommendations?
I’m using a generic CO₂ laser, model 1610 (1600 × 1000 mm, about 120W).
Here are the settings I’ve tried:

[Colin (Colin Worobetz)]

Unfortunately CO2 is going to have a hard time with glass - it’s not the right wavelength of laser light to directly mark glass without fracturing it as you’ve seen.

Some people have reported a layer of paint or similar can improve the result - but for glass usually you want a UV laser source, and some have better luck with Diode lasers as well https://www.youtube.com/watch?v=tcvGC18RZS8

[JimNM (James)]

Have you tried applying a layer of dry galvanized to the glass?

You may have better luck with a SHX font?

Wine glasses are fragile and break easily.

[MHN (Miel)]

haven’t tried that yet. I’m not really sure if the power is too high, but when I use less than 30%, it doesn’t engrave at all, it just blows air.

[Slipstrm111 (MT)]

I use rayzist photomask, then use fill to burn it off. Then I sandblast it smooth.