Laser Bending Ply Wood

Inspired by this post on the Glowforge forum I tried to bend wood without using 'living hinges' that go all the way trough the wood, but by cutting almost through the wood. The difference with the idea from het Glowforge forum is not to engrave but just to cut the lines.

To do this I had to cut lines side by side, almost trough the wood. The more lines, the smaller the radius of the bend can be.

First I created a huge amount of kindle wood, but when I managed to get the laser settings just right, and the result was great.

For a radius of 2,5 cm (1 inch) in 4 mm ply, I used a distance of 1 mm between the cuts and that worked just fine.

Materials:

• 4 mm ply wood

Tools:

• Lasercutter
• Clamps
• Glue
• Sanding paper
• Laquer
• Brush

Evansd2 engraved wedges into the wood to make the bends. That worked great but takes forever to do. I thought it would be much quicker to just cut lines. To make the same bends I need much more lines.

This experimenting phase is absolutely necessary before you start on the real piece. For me tho whole project was an experiment.

I finally ended up cutting 3 times as fast for the bends than I would do for the normal cutting lines.

Also I did the cutting from one side of the wood and the bending lines on the other side.

Finally I found out that you need to make the wood wet before bending, but making it wet also changed the dimensions of the wood, so you'll have to let it dry again before you can glue it and than still the dimensions probably have changed.

For my desired radius of 2,5 cm, my line distance of 1 mm worked fine in 4 mm ply wood.

Now that I have figured out how to do the bends, it is time to make something. My first attempt will be a simple bowl.

• First cut the long strip that will wrap all around the bowl and cut the bottom and rim.
• Than turn the strip over to cut in the bending lines. (I added a little engraved 1 x 1 mm square in the left top corner of the strip to align the cutting lines on the cut strip.)
  To keep the strip in place when it is bend around the bowl, I added a circle like in a puzzle piece. To make it look nice, I added some engraving to make it into an infinity symbol.
• Before you can bend the wood you'll need to soak it in hot water for a couple of minutes.

I added the original Gravit Designer files and the PDF laser files.

• I wrapped the wet strip around the bottom and the rim and used a clamp and rubber band to keep it in place while it was drying.
  When the wood was dry it kept it's shape already a little.
• Now I used clamps to glue it in place.

In the final picture you can see the infinity symbol that holds the wood together at the seam and the lips that hold the bottom and rim in place.

For the final box I want to make a cleaner design without the lips and with a lid.

The method for making the box is exactly the same as with the previous design, only now I have two strips inside each other and I used finger joints instead of the puzzle circle.

• Wrap the two wet strips of the box around the bottom and the two wet strips of the lid around the lip in the box. Hold them in place with clamps and rubber bands and let it dry.
• Glue it all together and clamp again.

To make this box a little nicer, I finished it of with lacquer.

• Sand the box with 400, 600, 800 and 1000 grit sand paper.
• Varnish with laquer.
• Let dry.
• Sand again.
• Varnish again.

You can see the bend lines on the inside of the box, but not on the outside.

I engraved the box with the IMDIB logo on the bottom.

The infinity symbol looks a bit nicer than the vinger joints, but I like them both.