A quick wooden Christmas decoration that will pack away flat for next year.**
It stands 20cm high and the base is 14cm diameter
I've been looking at some different cut patterns for flexible plywood (Living hinges, Super flexible double curvature surface, Curved laser bent wood), and coming up with my own. Along the way I stumbled across a three ingredient challenge here and got wondering what I could make in 3d that used no more than three flat pieces of plywood. And seen as it's nearly Christmas...
The flexibility of cut plywood depends on the lengths of the elements being bent. A spiral gives one long element that can be stretched further than it's diameter (empirical tests only!) Using only one spiral does create a nice looking tree but the forces acting on the wood are not balanced so it leans over. This design has two spirals that start and finish opposite each other so their forces balance out and give a straight tree.
It's a classic Christmas tree recipe so the three ingredients are;
- Star for the top
Just to cover my back in case anyone is thinking, 'But that's just a single piece of wood cut up, how is that three ingredients?' here are three extra three ingredient variations.
Traditional - Add a few coats of Danish oil and some candlelight for the Scandinavian look.
Chromatic - Brush on some green and brown paint/wood stain for a colourful variation.
I love Christmas - Add glue and glitter to the wood in generous measures for a sparkly kitsch Christmas tree.
If that's not quite enough 3's have a listen to this while you're cutting the plans...
**Maybe, this design puts a lot of twisting and bending stresses into the plywood. It will become more brittle over time and will probably keep better assembled. I've not had one long enough to know for sure..
Step 1: Making It
The SVG file for this design is here.
Other than that all you will need is;
- a small piece of 3mm plywood (30x20cm is plenty)
- any of the other two ingredients, eg glue/glitter, paint/woodstain, Danish oil/tea lights
Cut out the design in wood using a laser cutter. Lightly sand both sides of each piece with 300-600 grit paper to get a nice finish (Less important if you are planning to drown the final tree in glitter..)
The next step is to decorate the tree, it's much easier done flat pack. But it's worth putting the tree up first to see how it works and pre-bend the wood.
* Push the thin end of the trunk piece through the slot in the middle of the spirally branches piece.
* Carefully push the trunk upwards, holding the outside of the branches, to stretch the spirals down to the base of the trunk. There is a bit of spare give in the design but gentle and slow are the keywords here.
* Hook one side of the trunk cross piece over the outside ring of the branches. Line it up to the ends of the spirals as shown or it won't fit.
* Push the other side of the trunk cross piece over the ring and jiggle it until both sides slot into place.
* Put the star on the top. NB the jigsaw piece might fit better if you flip it over because of the way the laser is focused.
Step 2: Decorating Your Tree
It's much easier to decorate a flat pack tree, so carefully dismantle the branches and get creative!
If you favour the wood look all you need is a couple of coats of wax or Danish oil on both sides of all three pieces. In the new year I am going to look at grain filling before the Danish oil for a more glossy finish, but that would knock candlelight off the three ingredients list..
For the trunk of this tree I've used wood stain to give a colour wash that brings out the texture of the grain. For the branches and the star I used acrylic paints. Applied with a brush you can get a nice pine needle effect. If you tend to splash paint around quite freely it's worth assembling the painted tree before it dries; otherwise you might find the spirals get stuck together.
I love Christmas
It's the most glittery time of the year. So kitsch lovers shouldn't need any more excuse to get the glitter out. Paint on the glue and sprinkle away. Like with the paint it's best assembled wet to stop the branches sticking together. Remember not to glitter the very top of the trunk until after the tree is assembled; else you won't be able to fit it through the slot in the branches.
NB I only had glitter in primary colours but just like an RGB monitor it seems it's possible to mix your own glitter colours. (Ish, if you squint and don't look too close I think my mix or red and yellow, with a touch of blue is a reasonably passable brown..)
It's been suggested I try adding a zig-zag to the spirals to give a more tree like finish. I'd also like to try varying the width of the spiral, making it thicker at the bottom, to see how much that changes the profile of the finished tree. The files are here if you've got more time than me to try it, otherwise it'll be next December's project.