Recycle Styrofoam Into Hard Plastic Jewelry
Introduction: Recycle Styrofoam Into Hard Plastic Jewelry
I'd like to begin my first Instructable with a little grade school science lesson.
Styrofoam is the trade name for expanded polystyrene. "Expanded" means that it's filled with air to make it lightweight, which makes it very hard to clean and therefore very hard to recycle. There are a lot of places where you can't recycle Styrofoam locally at all. If you throw it away, it ends up in a landfill with an estimated decomposition time of 500 years. It will outlive you, your children, your grandchildren, your great-grandchildren...
I've always wanted to repurpose plastic and cast it into something new, but melting plastic is extremely toxic and I don't have a space with proper ventilation and other safety measures to do my work in. The point is, I wanted a safe way to upcycle Styrofoam into something useful without creating a safety hazard.
Styrofoam can be dissolved by using an organic solvent. This isn't melting, as you don't change the temperature. This also isn't a chemical change (i.e. something that could produce another substance as a result.) It's a physical change, similar to dissolving table salt in water. Styrofoam is essentially granular, like salt, and dissolves in organic solvents (e.g. acetone) like salt dissolves in water. The resulting plastic goo can be cast in a mold, and dries into hard polystyrene! (Learn more about this process here.)
Acetone is sold as both nail polish remover and paint thinner. It's safe when compared to substances such as hot melted plastic, though I encourage you to read the MSDS of any craft material you use and ventilate your working area well. (Fun fact: acetone can actually be produced by the human body!)
Some notes on materials:
* Your mixing container and stirring implement must be made of materials that don't react with acetone. 440
Silicone, metal/steel, wood, ceramic, and glass are all safe to my knowledge.
* Your mold must be silicone, not plastic. Silicone molds are very easy to work with and you can even make your own! For this project, I have had the best luck with simple shapes without many sharp corners. If your shape is too small/thin in any place, it might break. The mold I use here is 26x29mm. (I purchased my mold here!)
* Acetone is highly flammable. Don't use the tools from this project for anything food-related and don't expose them to heat!
* Disclaimer: No crafting process can be 100% perfectly eco-friendly -- I still use acrylic paints here, and though they are made of plastic, this project reduces waste instead of producing waste so I consider it a win. You can also try other paints that don't use synthetic binders! I haven't personally had the chance to do so yet, so I'd be excited to see the results if anybody tries it.
Supplies
Casting:
* Expanded Polystyrene / Styrofoam
* 100% acetone
* Container for mixing
* Stirring tool
* Silicone mold of your choosing
Decorating:
* Assorted sandpaper
* Chalk paint, especially if your mold has a shiny surface
* Paintbrush
* Cyanoacrylic glue, or any glue with similar bonding properties
* Jewelry findings, I've used glue-on necklace bails and tie tack pin backings
* Any other paints, finishes, embellishments, etc. of your choosing!
Step 1: Fill the Bottom of Your Container With Acetone
The exact amount doesn't matter as long as you have enough to cover the bottom of the container and submerge small pieces, because the Styrofoam doesn't need to absorb all of the acetone, just enough to lose its shape. I usually use 1-2 tablespoons.
Step 2: Drop Bits of Styrofoam Into Your Container
The Styrofoam will fizzle and dissolve into a plastic goo. Note that most of its original volume was actually air. The fizzling is this air being released. With the air gone, the resulting polystyrene is much denser and the volume decreases substantially, meaning that the volume of Styrofoam you need in the beginning will be greater than the volume of your mold.
Keep going until you have enough plastic goo to fill your mold. Stir frequently to collect it into one mass. I recommend working quickly because it gets harder to work with when it starts to dry! 254