Engraving on Black Flask - Anyone have good settings?

Hello- I engraved a few beautiful designs on black flasks with no issue - then using the same setting Im not able to replicate the results.

I used the silver MacBook Pro setting- first round had great results

Cant seem to replicate it-

Anyone have any suggestions?

Can you be more specific regarding the flask. Is it powder coated, anodized aluminum, or what? Specifically, what seems wrong with the results? Photos would help.

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I used 380 speed, / Full power and got great results with these:



Hello what did you use as the material setting?

Hello Its power coating - - Its having trouble on the curves- engraves fine in the middle-

Thank you for you time !

I set it to uncertified material.

You have curved surface so the laser focus isn’t going to be “right” across the entire surface. For best results, you want the focus to be about halfway between the point that’s closest to the laser and the point that’s furthest away. Don’t let the GF auto-focus. Measure the thickness of the flask at the thickest point and use that for the height of your material, but subtract off a couple of mm so the focus is mid-way between the closest and furthest points from the printhead…

GF is making changes/improvements to things all the time. Autofocus is a fairly new change that could easily be affecting your results compared to before. Manually entering focus height might get you back to where you were before.


The laser has to focus at a single level. Anything above or below will not receive the full power. If you focus on the middle the curves will be progressively worse. If you focus below the middle the outer parts will be better but the middle not so good.

… except they had success in the past.

So, I wonder, are these the exact same flask? Could it be the earlier ones had less of a curve across the engrave?

Thank you all - I was able to get this to work Bc of your help!


Did you tape these before engraving? I bought some very similar ones and was going to give it a try.

I did not, and got clean results.

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I thought they specifically mention in the GF video that it works on curved surfaces and shows a MacBook Pro being engraved. Does it work or doesn’t it? How much of a curved surface is allowed?

I have engraved on curved flasks with success. Currently the Glowforge doesn’t change its focus on the fly. There is one fixed focus height per design element. Results of engraving on curved surfaces are going to vary and be influenced by the severity of the curve, the complexity of the design and the type of material being engraved. A curved wooden spoon is going to have a different result than an anodized aluminum mac book case.

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The best cut will be at the height noted. My point was that if that the height is set at the very top of the curve then everything below will be progressively worse. However, by setting the height at midway between the highest and lowest point you will have the best cut at that level and worse as you go above or below but that way you get twice as much acceptable marking as you do only using half what is available.

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I used the macbook setting as the material choice, removed my crumb tray, and taped the flask to 1/4" plywood. That worked for me but the designs on the edges needed a second pass. This could be because they were too small or because of the curve, not sure. I may try to reposition the design and run it again or just start with a new flask.


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