Introduction: Up Cycle Plastic Milk Bottle Into Geometric Parts Dish

About: I'm an applied physicist by training(phd Yale 2006, BA Berkeley 1998, math and physics), and have done physics research in the federal government and product development in the private sector, starting two of …

If you're like me you have two related problems:

  1. you generate plastic bottle trash from consuming milk, water or juice at home regularly which you don't want to waste
  2. You have tons of junk that needs a handy place to put that's not long term storage but also not just out in a pile. In other words, a organizer dish of some kind.

In this project we will up-cycle HDPE bottles used for milk, juice and water into dishes based on Platonic solids.

Step 1: Gather the Materials and Tools

Materials and tools you need are:

  1. HDPE bottle(recycle symbol "2")
  2. tweezers and or pliers(preferably both)
  3. candle and lighter for flame
  4. marker
  5. scissors
  6. A ruler
  7. Something sharp that can be used to score things such as can opener as shown(end of scissors also works for this)
  8. Square or pentagon template depending on if you prefer the cube(which is made from squares) or the dodecahedron(made from pentagons)

I recommend starting with the dodecahedron, since I find the dish more useful, easier to make, and more aesthetically pleasing. The cube is probably more useful as part of other larger projects or as one of a larger number of small bins put into a larger bin.

For more information on the square and pentagon and how they fit into the Platonic solids, see my other post on this site, here:

And for another example of the plastic welding I show here see also my triangular tube here:

Step 2: Trace the "net", or Pattern, of the Polyhedron

As shown in the pictures and as shown in my other tutorial here trace the squares and pentagons to get 6 pentagons with 5 around one or a row of 4 squares with a fifth connected to a side of one of them. After you trace the core shapes, add the weld tabs by hand with the marker. This is done by eye/hand to be a few mm on the sides that will be joined as shown in the pictures.

Step 3: Cut Out and Score

Now cut out with scissors around the outside of the pattern. Then score with a ruler and sharp tool like a can opener along the folds. All the "major" folds which connect the squares or pentagons should get scored on one side and the tabs all get scored on the other(doesn't matter which is witch though). When everything is scored, fold each crease in the direction opposite the side you scored. Fold and refold and mold by hand as needed to get a clean looking rough assembly before the weld step(next).

Step 4: Weld the Joints With a Candle and Tweezers And/or Pliers

I used to very carefully melt both sides of a HDPE plastic weld joint, the carefully push them together. I've since learned that just letting the mold tabs catch fire and burn for a second or so is faster and works just as well. This will take several tries to get good at since you have to sort of do it by feel, but this stuff burns really clean and not fast, so just try it. Ideally, if you get it just right, you can have the fire consume about half the plastic in the tab, with the remaining half creating a good water tight seal. I recommend first doing a quick tack weld on each corner to hold the whole thing into position before finishing the welds to make them watertight if that is something you want to do. Also, if being watertight is a goal, part of what is nice is how fast you can leak check and fix a leak with this method. Just put water in it, mark where it leaks, and go back to your flame to either squeeze the leak shut if you have enough plastic still, or add a patch from your remaining scrap HDEP if not.

Step 5: Add Finishing Touches, Fill With Junk

After the joints basically all work, you can make them prettier by heating across the whole end of a joint tab enough to get it very glassy, then pushing the side of the tweezers alone the whole thing on one side to bend it over and make a smoother joint. This process could also include steps to add further decorative flourishes by hand by sculpting the plastic in its glass state with any metal implement you choose. When you're happy with the result, it's ready to be filled with Science Junk as shown.

Also, note that since this is clean food safe plastic salvaged from your own fridge, and it's watertight, you can use this as a food dish for a condiment or something. Probably it's not great to do this many times since the small fissures will be hard to get really clean, but you could always redeploy the flame in your cleaning process to fix that.

Finally, if you make a better version, share that! I want to see 2d models shared freely of cut and welded plastic trash eventually compete with 3d printing for creative plastics crafting. Let's make that happen!

Fire Challenge 2017

Participated in the
Fire Challenge 2017