This page describes a laser engraving setting published for Ardoise at 5 mm, tested on a Full Spectrum Laser P-Series 24 fitted with a CO2 90W source (10,600 nm CO2, 90 W). It states the exact machine, source, material, thickness and operation of the test; power, speed and number of passes are shown with a Premium pass.
Why those four facts matter: a engraving setting that works on Ardoise at 5 mm does not transfer to another thickness, nor to another source. A 10,600 nm CO2 rated 90 W does not deposit the same energy as a stronger module, and the speed has to be adjusted accordingly. Copying a number without checking those four points is the first cause of a ruined part.
Published by LaserSettings (estimation). No other workshop has confirmed it yet: treat it as a starting point, and confirm it from your account if you reproduce it.
No photo comes with this setting yet. If you reproduce it, publish yours from your account: a picture of the result is worth more than a line of numbers.
Recommended routine before running the part: clean the lens, redo the focus, engrave a small test grid on an offcut of the same Ardoise, then adjust the speed rather than the power. Work with fume extraction and air assist, wear glasses rated for 10,600 nm CO2, and never leave the machine unattended.
Full Spectrum Laser offers water-cooled desktop and workshop CO2 machines plus fibre markers. Active cooling allows long passes without power loss: a cutting setting holds across a whole board, which is not the case with a diode that heats up.
Slate is the most forgiving material of all: engraving appears bright white on black with instant contrast and almost no way to get it wrong. Perfect for coasters, signs and personalised gifts.
Slate is not laser-cut, only engraved. The beam does not carve the stone, it flakes off a thin surface layer — that micro-flaking is what appears white.
High power at fast speed gives the best white. Unlike wood, a second pass improves nothing: it greys the result by re-burning the dust already released.
Slate is rarely flat. Focus at the centre of the engraved area, not at an edge, otherwise contrast shifts from one side of the piece to the other.
No toxic fumes, but very fine mineral dust you should not breathe: keep extraction running and wipe the piece with a cloth rather than blowing on it.
A little mineral oil or wax over the whole piece deepens the black background and makes the white engraving pop dramatically. On a coaster, use a neutral food-safe oil.