Recycle Styrofoam Into Hard Plastic Jewelry

556

25

13

Introduction: Recycle Styrofoam Into Hard Plastic Jewelry

About: Hi there! I'm Rainbow and I'm a 21 year old graduate student from the USA. Things I like include sustainable crafting, alternative fashion, and Minecraft. I also have celiac disease and do a lot of specialty g…

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. 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!

Step 3: Press the Plastic Into Your Mold

Scoop the substance out of your container and smooth it into the mold, being careful to fill every part.

Step 4: Wait for Your Piece to Dry

Please note that the back of your piece that's exposed to air won't be perfectly smooth! You may notice some air bubbles forming as the acetone evaporates. I pop those with a sewing needle or toothpick.

I get the best results when I flip the piece in the mold as soon as it's hard enough to remove without distorting it. This depends on the size, at least 12 hours in my experience. I usually wait around 48 hours for the piece to dry in its entirety before unmolding and decorating it.

Step 5: Unmold

And bask in the glory of both creating something cool and saving plastic from a landfill!

Step 6: Sand

I used various grits on a sanding sponge to smooth the blemishes out. Some molds, like mine, create pieces that are shiny, so it's important to sand those a bit so your paint will stick.

Step 7: Paint a Base Coat With Chalk Paint

I specify chalk paint because, in my experience, chalk paint will stick to anything, and anything will stick to it, so it makes an excellent primer for plastics that might otherwise not take paint well.

I usually do two coats to cover up any little divots on the surface of the piece!

Step 8: Decorate!

You can do anything you want here! For my pieces, I painted a color coat with acrylic enamels or multi-surface acrylic paints and added spots with the white chalk paint. I also added a layer of glow-in-the-dark paint, but that doesn't show up well on camera! I sealed the pieces with Mod Podge Dimensional Magic. (For a more durable finish, I'd recommend using a clear enamel, but I didn't have any when I made this.)

Step 9: Add Your Findings

I've only used glue-on findings so far in these projects. Pictured here is a glue-on necklace bail!

Step 10: Done!

Thank you so much for reading! ヾ( °▽°)ノ*:・✧

I'm very excited to make more of these and hope to re-open my Etsy shop and stock it with recycled pieces soon.

I hope that you enjoyed this tutorial and that it helps you make something wonderful! Please let me know if you have any questions!

Trash to Treasure Contest

Participated in the
Trash to Treasure Contest

Be the First to Share

    Recommendations

    • Box Challenge

      Box Challenge
    • Explore Science Challenge

      Explore Science Challenge
    • Arduino Contest

      Arduino Contest

    13 Comments

    0
    bizigrams
    bizigrams

    6 weeks ago

    So cool! We get medication in Styrofoam and don't know what to do with it. I'm thinking of making small trinkets for kids to paint as gifts. Again, thank you!

    0
    Bellacricket
    Bellacricket

    Question 6 weeks ago on Step 10

    Very cool. I have been saving styrofoam packing pieces because you can't recycle it here. My question is why must you use only silicone molds?

    0
    RainbowPrincette
    RainbowPrincette

    Answer 6 weeks ago

    Thanks for your comment! I used silicone molds because they are flexible, release materials very easily, and don't react with acetone. I haven't tried plaster or concrete molds because I suspect they'd be difficult to release, but there's a possibility that they would also work if anybody wants to test them! I'd just steer clear of any molds containing plastic because it could react with the acetone and get damaged. Hope this helps!

    0
    Bellacricket
    Bellacricket

    Reply 6 weeks ago

    Thanks, it does help. I thought it was because of the polystyrene. So I was thinking in the wrong direction. I'm going to start messing around with cement again and I am looking for a way to make molds for that. I tried to make some silicone molds on the cheap last year, and it wasn't as successful as I had hoped. Onward and upward!

    0
    RainbowPrincette
    RainbowPrincette

    Reply 6 weeks ago

    Wahoo! Best of luck to you, can't wait to see what you make!

    0
    Hippo13
    Hippo13

    Question 6 weeks ago

    Could you tint the melted styrofoam before you put it in the mold?

    0
    RainbowPrincette
    RainbowPrincette

    Answer 6 weeks ago

    Thanks for your question! I've tried tinting the plastic by mixing acrylic paint into it while it's still pliable. It took some work to incorporate the paint into the mixture, but it did tint the final object. I ended up with a pastel color, so if you're going for a saturated or dark color you might need more concentrated pigment.

    The next time I'm crafting, I'll try tinting it again and take a picture for reference if I remember! In the end I personally prefer to paint over my pieces to mask the little divots and imperfections, so whether tinting or painting is better depends on what you want your final product to look like.

    Hope this helps! If you make anything I'd love to see it! ⸜( ˙˘˙)⸝

    0
    Brass Paperclip
    Brass Paperclip

    6 weeks ago

    This is very, very cool! I am imagining lots of possibilities for this. Thanks for sharing!

    0
    ellaolive22
    ellaolive22

    6 weeks ago

    Love this idea... :)

    0
    rnjenny
    rnjenny

    6 weeks ago

    Very neat. I might play around with this.

    0
    RainbowPrincette
    RainbowPrincette

    Reply 6 weeks ago

    Thank you! If you do, I'd love to see what you make! :]

    1
    seamster
    seamster

    6 weeks ago

    Clever use of materials, and a great result too!

    0
    RainbowPrincette
    RainbowPrincette

    Reply 6 weeks ago

    Thank you! ⸜( ˙˘˙)⸝