Pits/holes in glass around edges

Does anyone know why I am getting these pits, or random holes in the image and around the edge of my image in the glass?
Settings are: Xtool D1 20w, Speed 7500, power 75% Bi-directional pattern, Line interval 0.100 mm, lines per inch 254.0, number of passes 1.

Are you using some kind of coating on the glass?


Yes I have tried flat black spray paint, and in the picture I used CerMark

I use lbt100 spray for the co2, when I tried it with my ss laser, it didn’t work out too well… My communications with them was it was made for co2, not ss led type lasers…

I think both Cermark and LBT100 are about the same type/kind of spray.

Can you scrape it off? That would indicate it isn’t bonding to the material properly… Have you used it before with good results?


No I have not used it before, and no it will not scrape off, it looks like the laser is adding extra pulses randomly during the job? Maybe I need to try a different image with a fresh new creation? The whole image looks a little rough around the edges as well. Can you tell me if the setting I am using look like a good for this machine, my test looked good?

Have no idea with the settings for your machine… maybe someone will come along and advise you…

However, it sounds like you have tested it and have the right settings…

Maybe something else is happening to the coating… looks rather hot around the edges…