Make ANYTHING With Recycled River Plastic

This project was initiated by one of the many problems facing the Mekong Delta: plastic waste flooding the many rivers. This plastic is disposed of by people upstream, who are not aware of the damage plastic can do to the environment. By collecting this plastic, it will be prevented from flowing in the sea where it's even harder to collect. This collected plastic can be recycled into various new products. But every product would require a new mold of some sort. By recycling the plastic into an intermediate good, like in this case plastic beams, the production can be simple and the applications can vairy wildy.

I started my proces with a goal of designing products helping out people in the Mekong Delta in the south of Vietnam. I restricted myself to only the recycled river plastic and local products. The region is extremely vulnerable to climate change, as it's a low laying area at the sea which is dependant on rivers heightening the land. Upstream containment of the rivers and extraction of groundwater are resulting in the subsidence in the area, while the sea level is rising.

I designed a few products with the plastic, but I'll only show one as an example.

I'll show you how you can make your own products with plastic beams made from recycled (river) plastic. I will even go over how to make modular connection pieces to make complex structures.

The shape of your plastic beams will only be restricted by the shape of your mold, so go crazy!

Machines:

• Extruder (in this case: JW-machines Extruder 2018)
• Waterjet or CNC mill
• Welding machine
• Oven (optional)
• Injection Press (in this case: Abor Injection Pers 2020)

For film plastics:

• Agglomerator

For non film plastics:

• Shredder (in this case: JW-machines AM 2018-200 Twinspeed Shredder)

Tools:

• Drill press & Drill bits (2mm & 10mm)
• Metal saw (if waterjet and CNC mill aren't available)
• Metal file
• Large barrel or bucket (large enough for 2x the amount of plastic you have)
• Baking tray (optional)
• Heat gun
• Heat resistant gloves

For the material:

• Waste (river) plastic
• (Optional) soot

For the Beam Mold:

• Metal beam (any length, any shape)
• Sheet metal (between 4mm & 6mm)
• 4x M8 screws
• 4x M8 washers
• 4x M8 bolts
• 1/2" steel gas end cap with outer thread (This fits my extruder, yours can differ)

For the Connection Piece Mold:

• Sheel metal (the thickest you can find)
• Screws (depends on you mold design)
• Washers
• Bolts

Due to the rising sea levels, farmers near the coast have to build higher dikes to prevent their crops from being flooded. This practise is labour intensive and need to be built properly to be able to prevent water from coming in.

My idea is a floating rice bed, made out of recycled river plastic and coir rope. Although these floating rice beds won't stop the water from coming land inwards, they will help farmers (near the coast) adapt to the rising sea levels. As the farmers don't have to fear the water anymore.

The design is designed around plastic beams. Beams are an intermediate good, meaning that they are halfway between a raw material and a finished good, just like wooden beams and metal profiles are. By doing this, the beams are not restricted by a design and thus can be used in many different other cases.

The connection pieces are designed to connect two beams in the corners. But they are not specificaly designed to only be used in this design. They consist of a single base block, where the 'beam recieving' blocks can be melted to. A more detailed assembly can be seen in the chapter 'Assembly'. They are not necessary though, because a same connection can be made with a Bridle Joint, with a hole and then a rope through it.

The connection pieces I designed are 'modular', meaning that they can be assembled in many different ways: In a corner piece, an L-shaped piece, a T-shaped piece, you name it. By doing this, you don't have to have different mould for every different connection piece.

You can get your plastic from any source you want. In my case, the foundation GoClean de Liemers gave us 80 kilograms of waste collected from a few kilometers of a river beaches. This batch won't be seperated by material type in this case. The only things that were taken out were PVC, PET bottles and metal stuff.

If you can get your hand on separated plastics, that's great! It'll ensure more reliable properties.

Before shredding any of your plastic, I highly recommend you clean your plastics. By doing that, you'll get rid of most of the sand, metals and other debris that are in or on the plastics. This will ensure your shredder or agglomerator blades will last way longer!

Cleaning

Cleaning can be done multiple ways. I did it my washing after shredding, which I do not recommend. By putting the plastics in a big barrel of water, most of the plastics will float and the sand will sink to the bottom. Mix the plastics and water thoroughly and ways for the water to be completely still. This can take up to 45 minutes.

If the water has come to a halt, you can use a sieve to remove the floating plastic from the water and let the water drip for a few seconds before placing it on a baking tray. Once all the pieces of plastic are removed from the water and are placed on the baking tray, it's time for drying!

Drying

By drying the plastic, you remove most of the surface and absorbed water. This will ensure that as little water vapor will form while in the extruder. The water vapor will create little air bubbles that affect the materialproperties. You can do this with an oven or you can use the sun.

With ✦nature✦

If you don't have access to an oven, the sun is a powerful water evaporator as well. Although, you're more dependant on the weather.

I placed all my plastic on a big sheet of cardboard, because this will already absorb some of the water that's on the plastic. Spread your plastic evenly over the entirety of your piece of cardbox and let the sun do the rest. The best place for this is near windows where the sun is brightest. Depending on the weather, the plastic will be dry in 1 to 3 days.

With an oven

The baking trays with the pieces of plastic can be put in the oven. Set the oven to 110°C, this will evaporate the water, but it will not melt the plastics. Let it dry for around two hours. If the plastics aren't dry after two hours, scoop it around and give it another hour.

After the plastic is completely dry and cooled down, put it in a airtight containers. This will ensure the plastic doesn't reabsorb water. Or use it immediately.

Now you can choose if you wan't to separate your plastics by plastic type. I did not do it because my plastic was preshredded so that's impossible for me. Separated plastics will have more consistent material properties than a beam made out of mixed plastics.

As I described in the supplies section, depending on your kinds of plastics you'll need different kinds of shredders. For film plastics (like plastic bags, trash bags, and thin foils) you WILL need an agglomerator. A normal shredder cannot tear the flexible and tough plastic of bags into pieces small enough for the extruder.

Using an agglomerator

An agglomerator will slightly heat up the plastic (to around 80°C), so that plastic bags and foils will contract. This will make a small piece of plastic that's able to be shredded. The knives in the bottom of the machine will shred these pieces of plastic.

Using a schredder

A shredder is more commonly available. Although it is not great with plastic bags and foils, it is great with harder pieces of plastic like bottles.

The beam mold

For the beam mold, I followed the 'Make a mould to extrude beams' tutorial from Precious Plastic. It is a great and simple way of making lots of beams. They even made tutorials of how to make different shapes of beams. Make whatever beam your design needs. And use whatever materials you have handy.

The connection piece mold

The connection piece can be made in different ways. I'll be using an injection press with a mold made out of layered sheet metal. For more injection mold ideas, tips and tricks, again, see the Precious Plastic site. They have great instructions on how to make your mold work.

Extruder

My extruder has to preheat (to the melting temperature of your plastic) for about 1 hour to make sure the entirety of the melting zone is up to temperature. Get to know your own extuder on how much time it needs to preheat. If you're not sure: more time is always better!

If you have an oven handy that's big enough for your mold, use it! If you don't, use a heat gun for at least 5-10 minutes! A warm (around 70C) mold makes sure your beam has a smoother surface, if desired. Read more about different beam textures in one of Precious Plastic's tutorials.

Now you can add your material to the hopper. You can either calculate the amount of plastic you need and add all of that to the hopper, or you can just add small amounts bit by bit. I usually go with the latter.

Just before you screw on your mold, extrude a bit of material. This will get rid of any gunk or solidified plastic at the end. Grab the plastic out of the extruder and screw your mold on!

Injection Press

Begin by putting your extrudion mold in an oven. I heated mine up to around 150C-200C, so that the plastic doesn't solidify immediately and it can fill the mold.

My injection press is not the easiest to use. The heating elements are not that accurate and there is only heating from the outside, so the inside doesn't get hot enough. But by pressing the plastic out and putting it back on top a few times, most of the plastic does get melted. My heating elements were set to 400C, but it measured to be only 200C.

Only start when your mold and plastic are up to temperature !

Extruder

Now that your mold is on the extruder, you can finally start! Turn the motor on and let the machine do the rest. Well, it's not that simple. So here are few tips for while it's extruding:

• Put a (non plastic) meterstick or a ruler into the beam while it's extruding. This way you keep an eye on the extrusion speed and progress.
• Watch the hopper closely. Make sure there's enough plastic and that's it is extruding the plastic properly.
• If you have a big mold, you can keep it warm with a heat gun while extruding.

If the plastic comes out of the end of the mold, stop the motor! Put on your heat resistant cloves and screw off the mold. Tip from Precious Plastic: Dip the nozzle in a water bath. This stop plastic from oozing out. You can either get a container of water big enough for the mold to cool it down, or you can let it cool down in the open air (this can take up to 2-3 hours). After that, screw off the bolts and lightly tap the open side with a stick and a hammer. If the mold and plastic are cooled off properly, they will slide out of eachother.

Injection press

Now that your plastic and mold are up to temperature, you can start! Screw your mold onto the injection press and get ready, because it needs to happen quick. Once the mold is secure on the end, start pressing the plastic in, slow but steady! There can't be enough plastic, but there can be too little.

When the plastic comes out of the ventilation holes, stop pressing and take out the 'plunger (the thing that pushes the plastic)'. Now screw off the mold and let it cool down in some water. !!!WARNING: DON'T LET YOUR GLOVES GET WET. STEAM IS VERY HOT!!! Let it sit in the water until it's cool enough to handle with bare hands.

Now you can disassemble the mold. Depending on how good your mold is, this can vary from seconds to minutes. Once your object is out, let it cool down completely because the plastic is usually still warm on the inside.

Now that every part is ready, it's time for assembly!

I still had to drill some holes here and there, that only took an hour.