Settings for Engraving on Slate

put a light coat of mineral oil on the slate before etching.

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Pre treat with spray shellac and use full power and speed. I also use spray shellac for engraving on canvas. Its great to have around and it food safe.


I put a light coat of mineral oil on the slate. Typical height of a slate coaster (including rubber foot) is 0.34". I run at: speed 600, power 80%, and 270 lines.

trying to figure out how — is this in a histogram setting? my guess though probably wrong

You pre treat with spray shellac, then engrave — then if you are going to use it for meats & cheeses (IOW food), are you going to spray shellac it again to protect the engraved areas so they don’t wear?

i use the “levels” settings in photoshop (ctrl-L)and move the sliders for mid values till they look good

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After that point, do you save it as a PDF or bring it into Illustrator and save as an SVG? I haven’t used Photoshop since I got my Glowforge several years back.

actually… i save it as an uncompressed .jpg…
Glowforge does a nice job of ripping bitmapped files as well like .bmps and .jpgs…

then… on slate i use vary intensity to burn… and on wood i usually use “dots”

So I’m confused! I did everything exactly as everyone suggested and somehow ended up with this. Now I know someone is going to say my machine must have been bumped during my second pass but I only did one pass so there is no reason for it to look like this.

Was this done without the honeycomb tray?

The good news is that you can sand the slate and get back to a fresh surface to re-engrave once you figure out your issue with the GF or design.

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I think it’s in the file. The image was inadvertently doubled somehow. Or maybe it was doubled in the GF GUI.

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It was one of my wheels were cracked, all fixed and going for it again right now

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Hi I was wondering how you got it to shadow the slate

not sure the exact meaning of your question - but happy to help… the slate itself is “black” (dark)
the images glowforge burns into them make the slate go “white” (actually just a light shade of grey)
so… i take my image in photoshop and invert it (make it a negative)
verything i want white/light is actually black in the file… that shadow or fade from left to right is in the photo itself… dramatic lighting makes for those darker shadows (and painting on top of them in photoshop)

is that what you’re asking?

Yes that is. Thank you so much. And sorry, I didn’t realize I had a message. Thank you so much for your help