I’ve been searching the forum for a while, and I see multiple people refer to engraving sandstone, but I can’t find anyone mention any settings. Before I start taking random guesses, does anyone have recommendations for base settings for a darker engrave?
Lol, this could be useful, the ridge at the back of my property is mostly sandstone
So… “dark” isn’t really a way I’d describe most mineral/glass engravings, you usually have to add something (painting the engrave or using masking paper to char up and “color” the engrave). Here’s a post about it: Sandstone engraving!
Beyond using some sort of trick to color the engrave in – I’ve never tried sandstone, but it seems like you might get a “deeper” engrave than in some other types of stone since you can probably break the sand matrix pretty effectively with a laser… but there’s a big caveat.
When you lase stone, it doesn’t ablate, it cracks. This is a generalization – it depends a lot on the actual mineral you’re trying to hit. Those cracks tend to be white, not dark. There are probably exceptions, but I can’t think of any at the moment – most of the “dark” in an engrave is charred organic materials (sap, wood, leather, maybe some hydrocarbons in plastics or in the post above, whatever goop the masking tape left behind), and stone usually doesn’t have much if any organics in it.
The other caveat is that in general if you hit stone too hard, you generally get one of two major reactions:
1- in crystalline stones you’ll crack it severely enough that the edges of your engrave will get irregular and the rock will actually spall and break apart. You end up with a really rough engrave that probably isn’t what you’re going for.
2- for things like slate, you actually can melt some component of the surface (maybe the stone itself, maybe some sort of binder, I’ve never been sure which it is) and get little balls of glassy slag.
In both cases, that’s not ideal. Again, I’ve never tried sandstone, so I’m definitely not saying a deep engrave in sandstone is impossible, there are just some gotchas. If you have success, please post about it
For further reading and inspiration, I’d say try searching for “glass engrave crack” and “stone engrave”.
Also not done sandstone though I may have some coaster blanks in my someday-pile. But with travertine I get good depth with multiple passes - I do 3 but I know some folks will go to 5 (using the trick to get 5 in the # passes box). 3 always worked out for what I was doing (personalized coasters). Slate doesn’t seem to get any deeper with multiple passes but a sandy type of stone should. I have to brush out sandy bits from the travertine engraves.
“dark” was a poor choice of words. I’m looking for decent contrast.
This won’t work without sealing the sandstone, which I can’t do in this case.
I had seen this post, and unfortunately, no settings are mentioned.
I ran a couple of tests at 200/full and got somewhat acceptable results on 1/2" sandstone. There is some contrast due to the depth (about 1/128" to 1/64" in different areas), but only a little color.
Yeah bummer. I wonder if you could treat it with something and ablate it off? Maybe invert the engrave? Interesting challenge.
Actually borax would probably lower the melting point and give a flat surface of melted material. You can use the 20 Mule Team Borax sold as help with washing but make sure it is the borax and not that brand of soap that contains only soap. A jeweler friend made that mistake and could not figure out why his castings were so horrid.
If you can find cobalt carbonate to mix with it (as small as you can measure to a whole box of borax, one part in 5000 by weight or less ) it will make the finish blue to black as a result. I am anxious to try a lot of similar things but not put together the materials as yet.
I got this on a trip to Arizona. I am guessing it was laser etched. but I have no idea what power the laser was.
I’m bettng it was masked and painted, but just a guess.
The reason you get “color” in an etch or engrave wood or some other “organic” textile is because the laser is burning away the material, and the material changes color when it is burned. For glass, ceramic and stone, the laser doesn’t burn the material at all, it “ablates” it away with heat. The “albedo” (reflective specularity if you prefer) of the surface can change (glass goes from clear to frosted) but the color is unlikely to be any different because rock doesn’t burn (at least at our laser temps). if you want color in the stone, you need to add it before or after the etch. Treat the entire surface with a stain before etch and the etch will have the original color, or mask the surface before etch and then color the etched area before removing the masking…