Wood Raster Engraving

Six steps, and only one of them involves pressing start. Pick the board — light, even-grained and low-resin if you want contrast and repeatability. Clean and flatten it, because dust scatters the beam and a warped board engraves at two different depths. Orient the artwork with the grain where the figure is strong. Focus for this board’s thickness, every time, since a stale focus is the most common cause of a faint engrave. Run the test file on a scrap of the same stock — Boss ships engraving, cutting and scoring test files on the machine’s USB drive for exactly that. Then run the job with air assist on, so the smoke an engrave makes across the whole filled area is blown clear instead of dulling the surface and filming the lens. Boss’s published starting points for basswood and birch are 35% / 25% / 20% power at 350 mm/s with a 0.065 mm scan gap, on the 70 / 105 / 155 W tiers.

Light, even-grained and low in resin. Boss publishes settings for balsa, basswood, birch and birch plywood, which is a reasonable list of woods that behave predictably. Basswood and maple are the usual answers when contrast matters, because a dark engrave against a pale background is the whole effect. Birch plywood is the workhorse for anything that also gets cut. What causes trouble is the opposite end: dark species like walnut give you less contrast for the same engrave, dramatic grain engraves unevenly because the beam bites deeper into the soft early growth, resinous species smoke and char more, and knots are local density spikes that engrave differently from the board around them. Bamboo, cork and acacia all engrave — Boss publishes no chart for them, so treat any number you find as a starting point to prove on a test tile. If character matters more than consistency, buy the figured board and accept the variation; if you are making two hundred matching pieces, buy the boring one.

First check that darkness is the problem and not contrast. The engrave is dark because the surface has carbonised; how dark it looks depends just as much on the wood around it. On walnut, a perfect engrave still reads muted because the background is already brown — the fix there is a lighter board, not a hotter setting. Where the stock is right, go slower before you go hotter: more dwell time carbonises more without widening the mark as much as raw power does. Keep the piece in focus and the artwork at a sensible resolution, since a blurred edge reads as a weak engrave. Past a certain point more heat stops adding contrast and starts adding a smoky brown halo around the artwork, which makes the piece look worse while technically being darker — that is the ceiling, and the way past it is not the laser. Filling the engraved recess with paint, or inlaying a contrasting wood, gets you a genuinely darker mark without burning the board. Any post-engrave darkening product is woodworking craft rather than a Boss-published procedure — test it on scrap.

Often yes, with one condition that decides everything: you have to know what the coating is. You are not engraving wood any more, you are vaporising the finish into the cabinet and the room. A stain or lacquer you applied yourself is a known quantity, and engraving through it can give beautiful contrast because the artwork edge is exactly where the finish stops. A reclaimed board, a factory-finished panel, a painted salvage piece or pressure-treated lumber is an unknown coating until someone produces the safety data sheet — and a lot of “wood” surfaces are not wood at all: melamine facing, “wood-look” laminate and iron-on edge banding are frequently PVC, which releases hydrogen chloride and must never go in a laser at any setting. Expect film finishes to melt or discolour slightly beyond the engraved line, and expect to lower power compared with bare wood. If the piece is not yet finished, engraving first and finishing afterwards is the safer default.

Both work and they give different pieces, so pick by the look you want. Engrave first, then stain and the engraved areas — open, porous, effectively end grain — drink up far more stain than the surface around them, so the artwork ends up considerably darker than the board. That is a genuinely attractive effect and it is also the reason people are surprised by it. If you want the engrave and the surface to take stain evenly, seal the face with a thin wash coat first, then engrave, then stain. Stain first, then engrave and the beam removes the stained layer to reveal lighter wood underneath, so the artwork comes out lighter than the background — the reverse image, and a good answer on dark stock. The safety condition from the previous question applies: know what is in the stain before you vaporise it. Whichever order you choose, prove it on a scrap of the same board, because absorption varies by species far more than by product.

Start by removing what the laser left. A light sand with fine grit along the grain takes off surface soot and any raised fibres without touching the engrave itself, which sits below the surface. Then finish it as you would finish any wood, with one thing in mind: the engraved area is more absorbent than the rest of the piece, so oils and penetrating finishes will darken it more, and a film finish will pool slightly in a deep engrave. Both are usually desirable. A wipe-on or spray finish reaches into an engraved recess more evenly than a brushed one. For items that will be handled — coasters, boards, tags — a sealed surface also stops the engrave picking up dirt and going muddy over time. Boss publishes no finishing schedule for engraved wood, so every product choice here is ordinary woodworking practice; test it on a scrap of the same stock, especially over a deep engrave where a finish behaves differently from on a flat board.