Laser materials · Slate

Laser engraving slate

Slate is one of the easiest materials to engrave well. Diode, CO₂ and fiber lasers all mark it, it needs little power, and the light grey engraving on dark stone looks premium on coasters, signs, house numbers and memorial plaques.

How slate engraves

The laser doesn’t burn slate darker like wood. It roughens and lightens the surface, leaving a pale grey mark on the dark stone. That has two consequences. First, designs need to be prepared for a light mark on a dark background. Second, you can’t cut slate with a hobby laser; slate is engrave-only, so buy blanks already cut to shape.

Photos on slate

Because the laser makes slate lighter, a photo engraved as-is comes out like a negative. Invert it first: the slate preset in Photo Engrave inverts the image and adjusts the contrast for stone. Dithering styles with fine dots (Jarvis or Stucki) give smooth portraits; Atkinson gives punchier contrast on rougher slate.

Getting good contrast

• Don’t overdo the power. Too much heat breaks the surface into dust and the mark looks patchy. Slate usually wants less power than you expect.
• Brush off the dust after engraving with a soft brush.
• Wipe with a little oil afterwards. Oil darkens the untouched stone and makes the engraving stand out. Wipe off the excess.
• Seal coasters with a clear coat if they will see wet glasses.

Products that sell

Coasters (often in sets of four with felt or cork backs), house numbers, pet memorial plaques, cheese boards, door signs and photo keepsakes. Slate pairs well with a cut wooden stand or a gift box: the box generator can make a fitted box for a coaster set.

Marble, granite and tile

Dark polished granite engraves similarly and gives the best photo contrast of the stones. Marble marks lighter and more subtly. Glazed ceramic tile is trickier on a diode laser: darken the glaze with marking spray or matte black paint first, engrave, then wash the excess off.

Safety

Engraving slate releases fine stone dust. Run your extraction, and brush or wipe the dust off rather than blowing it into the air.

Settings

Slate needs modest power at moderate speed on most lasers. Starting values are on the xTool settings page and the other brand pages; run a small test card on the back of a blank to see how your slate responds.