Wood veneer inlays using laser engraving
TL;DR Laser engrave an indent to hold the veneer. Laser engrave the veneer on a aluminium tape backing. Align. Glue. Sand.
DIY:
- I have left 2 sheets of the aluminium tape on the laser shop shelves (you’ll need your own veneer).
- The tape I bought: Amazon link 150mm was the widest I could find, 50m was the shortest length I could find. I’ll probably donate some or all of the remainder to the Space soon.
- The veneer I bought: Ebay link
My first exposure to the concept was Laser Dave’s Mayan calendar. See the Youtube tutorial, but don’t use the masking tape mentioned in this video – read on instead.
I’m clumsy by nature, so the idea of being able to inlay something so incredibly detailed using the precision of the laser without having to manually align 1000 tiny bits really appealed to me!
The big idea in this technique is to engrave away the veneer you don’t want, leaving only the parts you do want, perfectly positioned to be embedded at one go! Even better, no kerf compensation is required.
The challenge with using the masking tape backing is that it can also burn, so you have to find the perfect power and speed settings to remove all the veneer without burning away the masking tape. My experiments in this regard were not successful. Also, the settings would vary for different veneers, and possibly even for different sheets of the same wood!
The more recent iteration swaps out the masking tape for aluminium tape. This is ingenious because our CO2 laser can’t cut aluminium, so you can just focus on engraving the veneer without worrying that you are going to engrave through the backing.
See the updated tutorial for the details.
Here’s my finished board, followed by the lessons I learnt:
Lesson 1: Speed and power settings
Its harder to find perfect speed and power settings for a single job than to just do multiple jobs until you achieve the desired result. This is especially true for a one-off combination of wood and veneer.
The first veneer engraving job removed the softer wood, but not the harder grain.
The second job removed all the veneer but left the adhesive from the backing tape. I needed even more engraving jobs to get rid of the adhesive.
Lesson 2: You can’t set the laser to engrave to a specific depth.
I did numerous engraving jobs until I got the depth I wanted. I used a small piece of the veneer butted up against an edge to assess the engraving depth. After the fact, I realised that I should have actually gone a bit deeper. The veneer protruded a lot and took a lot of sanding to remove.
Lesson 3: Burn off the adhesive
I didn’t do enough engraving passes to remove all the adhesive. I started cleaning it off the tape using isopropyl alcohol, but I was worried that I would dislodge some of the smaller bits, so I stopped. I ended up with some of the adhesive residue on the chopping board, which gunked up the sandpaper!
Lesson 4: Pressure
In the videos Dave uses a roller to press the veneer into the wood. I didn’t appreciate just how important this step is. I have several places on my board where you can press in the veneer because there is a void underneath it.
I also had clamping challenges because I was gluing up at home. Dave had another piece of wood the same size as the project, so it was easy for him to clamp. I didn’t, so all my pressure from one side.
Lesson 5: Warped veneer is not your friend
The veneer I used was warped and rippled. This had a minor impact on the engraving as some parts of the sheet were not fully in focus. The bigger issue was in combination with not pressing hard enough. The warp became really apparent when I started sanding, as the dust accumulated in the troughs.
Lesson 6: Tape adhesive vs wood glue
In a few places the tape adhesive won, and the veneer piece was pulled out of the board.
I realised that the direction of pull was a vector almost directly opposite the direction of pull of the wood glue.
I reduced this impact by folding the loose piece of tape flat in the direction of removal and then rolling it slowly along the cutting board.
Lesson 7: Reducing engraving time
Our laser engraves quite quickly, but I ended up doing about 10 engraving jobs in order to prepare the cutting board and the veneer.
Initially I used Inkscape’s Live Path Effect to block out the minimum veneer area to be engraved. However, that would have left some objects that were not going to be embedded. These would have prevented the press of the pieces into the board. I would have had to cut the tape along a complex outline.
I eventually just blocked off an easy-to-cut tape outline. I also had to rotate the objects to fit the smallish piece of veneer. I probably saved an hour in engraving time.
