As you may know, in Fablab Moscow we participate in the precious plastic project. We made the machines for plastic recycling and organise workshops where people can realise their ideas.

I made different injected objects (skate, bike pedals) but then I was looking for something universal, something that anyone need. So I thought about structures. Plastic is light, durable, shock proof. A plastic structure can be used as storage system, as table or chair basis.

In this instructables, I will show you different techniques that I explored to assemble injected plastic sticks: Injected plastic join, 3D printed join, welding.

Bonus: Ball pen out of recycled plastic tube.

Step 1: Inject the Parts

As shown in the video, the precious plastic injector has been used to make the parts. For the sticks, a simple aluminum tube has been used. For the joints, a three parts aluminum mould has been milled.

Step 2: Assembly

For this crane type structure, the joins are 3D printed. Milling moulds is expensive and time consuming so as a first prototype, I used 3D printing.

The vertical stick length are 74mm and the oblique ones are 162mm. The stick diameter is 7.4mm.

Step 3: Welding

Another convenient assembly method is welding. The main advantage is you don't need any join, you just hold the part in place. A hot air gun has been used to melt both sides then the parts are pressed together.