Bad Glass engraving

Using the Ortur LM3 with YRR. I have been testing and trying several settings but seems I am not getting anywhere. Here is my latest . If you see some areas are etched and others have striated lines through the letters. Looks horrible!!!
I prepped glass with black tempra paint. My settings are 1500/100 %. with 1 pass. My line interval is 0.100mm, lines /inch 254.
Can you shed some light on what I can adjust to improve and get the lines out of the image
Thank you in advance

It appears to me, that you lines are brush strokes from the tempera.

Do you need that much power?


the lines are more than likely application lines from the tempura paint. It a good idea to do multiple layers to make sure there is not these thin spots that cannot burn.

I use a 10w diode laser and i run it about 1200mm at like 11.8% power. I found less power made it better but we have different machines and burning different glass so I cannot speak on if it is an issue the burned parts look good just thing tempura.

I water my tempura down and spray it through a cheap HVLP detail spray gun. do two or three layers and have great results. I personally was never able to get a even coverage with a brush or sponge, some have, I was not so good.

I tried spray chalk paint, 1 coat. One pass at 1000/60% When it was done it had areas where the paint did not get etched off but was chipping. I used a razor blade and chipped of the coating and the glass underneath was etched??? Do you have any idea what I’m doing wrong? Speed to fast or too slow? Power to low or too high?
I have tried tests with different speeds and powers but not having luck Could you or anyone suggest a starting point so I could test from there? Any help appreciated. Thanks

When you have issues you have to analyze what the laser beam effect on the material is…

An dpssl can’t do glass, so you have to apply some indirect type of heat to get any kind of engraving.

You’re doing that with the tempera paint… you heat the paint, it heats the glass…

Same principle with this chalk coating… I’ve never heard of it, so I have no real idea what it is…

However, it is heating the coating up enough to fracture the glass underneath but not enough heat to remove the coating… It heats up, the glass underneath shatters, but the coating is not being vaporized.

Why did you pick a light color?

White reflects all of the spectrum and chalk probably isn’t too far behind.

Make sense?


The chalk paint I used was a charcoal color. It is made by Rustoleum. Yes this makes sense. Thanks.

I have not tried chalk paint personally. I have heard that etching primer works but any paint is a mess to clean up and I am super lazy so I do tempura because I can wash it off with water and put it down the sink. It is a little more of a hassle having to mix it but once again cleaning up my spray gun is quick with water. I know not everyone has that ability

If I were in your situation I would spray two coats next time to make sure the coverage is good and even and I would lower my power settings. I use 15 to 30 % power on a 10w diode laser. You have to play around with things different glass, different spray will all change things once you get it dont change anything big. once again if it were me I would try something like 30% at 1000 and then see if I could speed it up a little. I always try to go as fast with the least power on just about everything.

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