Holy Grail Project - Re-Usable Collapsible Cup from Sustainable Materials

Step 8 Bottom, Top, and Strap for the Cap

Now that you have the collapsible part made, it'll probably need a top and bottom. The bottom is simply a hexagonal peice, but the top obviously has to have a hole for the cap and a strap coming off it that the cap is attached with.

Again, I have provided a template for this - have a look. As with the previous one, it can be made to any scale to suit a personal cup, but if you're building to my specs, then the hexagon in the plan should be inscribed in a circle of 68mm.

The strap coming off the top hexagon (with the cap on the end) is designed so that it wraps fully around the bottom of the cup and plugs into the top, sealing the cup, and holding it in compressed form. Therefore, the first section of the strap should be the compressed height of your tube (in my case 2cm), followed by the width of the cup (for me, 6.5cm), followed by another depth, then a final peice with a hole cut out to accomodate the central cap.

The cup can also be closed when extended to form a travelmug, the strap forming a carry handle.

At this stage, use a marker to draw the plan, and cut a top (with strap) and bottom out the plastic. Line it up and fuse the edges as before with the soldering iron. Not much to go now...