Slate Engraving test runs

I have a bunch of slate floor tiles at home, and since engraving actually works quite well on slate I figured I need to do a proper test run.

What makes the floor tyles a bit less desirable to engrave is the lack of contrast. Since these are grey slate I think and not a black slate the final image can almost disappear if you are not viewing it from the right angle.

With this example in the photos I actually coated the engraving in black enamel and for the most part was happy with the results. I did need to increase my power since quite a few bits of enamel was not burnt through. I removed those bits just with a hand grinder.

At first I thought I could run the laser again over the same space but the registration was off by 3mm and when I noticed it had already removed some of the detail in the roses on the bottom.

Before I engrave I also do a clear coat which is really the least effort to at least darken the surface slightly but it still lends itself to low contrast on the image. Someone said I should try oil which I can try on the clean slate, and the background might be a shade darker, and ideally I would want to see if the oil penetrates which might reduce contrast if the lower layers are also darkened.

A raw base with no coating on the bottom, before I decide I want to do an enamel test. I lost quite a bit of detail due to different pixel requirements but the test showed that the enamel would be great for contrast. Obviously. However it did not prepare me for the added thickness requiring higher power to burn at.

Overall I am happy with the tests, mistakes were made but at least I know which ones. I do now want to try and split and break these floor tiles since they are way easier to get than roof or coaster slate tiles.