I found a stack of bisque (unglazed / unfinished) tiles in my mom’s attic, and have been experimenting with them between other projects. Unlike with glazed tiles, the laser darkens them, although so far I haven’t gotten a real DARK dark result. I think the heat of the laser must be enough to “fire” the parts it hits, because it doesn’t seem like running a second pass ever changes anything.
Here’s my best one so far–I hit it with a couple of coats of spray lacquer to see what would happen. It didn’t change the engrave at all, but it gave the tile itself kind of a yellowed “antique” look:
This was the first one I did; not as aggressive with the settings, so it didn’t come out as dark, and like I said, doing another pass didn’t change it:
The laser does actually vaporize some of the surface. (I haven’t tried vary power on it yet, that’s on my list!)
On this one I tried painting it black and doing a reverse engrave. I used a primer plus paint spray, but I think the unglazed surface soaked up too much color for it to really “pop.”
