Polystyrene transparency

Hey there!

On my first adventure with Precious Plastic I chose to try out polystyrene with the compression machine and see what happens. Doing so I realized we had basically two “colors”: transparent and black.

So I decided to combine them, playing with transparency and seeing how far can we get.


The dimensions of the mould I used are 10x10cm. Height of the piece will be determined by the amount of plastic, with 60 grams of PS you get 8mm approximately.

hey @thups
I just noticed this very interesting thread, i’ve been doing couple tryouts with PS

So to answer your question, there are 3 categories of PS
Cristal PS : always transparent
Choc PS : coloured version
Expanded PS : not the same at all; doesn’t react the same when put to heat, it is made of TONS of miny bubbles filled of air(?); check out @coira ‘s tries with Expanded PS on the V4 subdirectory !

Funny enough, i find many similarities between PLA and PS in finished product, the main difference being that PLA’s transparent doesn’t maintain as much when going bigger thickness as PS does

here is a photo of one of our PS products, we managed to put in place a little technique to “block” different colours in the inside (not exterior) part of the product 😀

Cheers !

Did you use Expanded Polystyrene to achieve this? How much polystyrene is required to achieve that transparent tile in the end? Did you shred the polystyrene before doing the compression?

Very interesting 🙂
Is there a way to get a more crystal-clear-looking result?
What about coloring the transparent PS with something that could keep it translucid, is that technically possible ?

Keep up the good work 😉

The image you put together of the different percentages is a huge help. Thank you for that!

@gujonon Interesantes resultados.
Gracias desde Mallorca (Spain)

Great work @gujonon

Thank you for sharing with us

@oceanplastic Thank you so much Diego!

@gujonon thanks for being so thorough with your insights. this is very valuable information. the results are so beautiful!

Thanks @timslab ! Timing depends on the tools you have: by hand it can take you about an hour to do it properly, and with a machine less, like 15 minutes. The more time you spend sanding and polishing the better surface you’ll get!

Nice write up @gujonon… I’m quite surprised at how transparent the plastic remains even after heat / contact with mold etc. Did you wash the plastic pre-shred or after shred?
How long does it take to polish a part to shiny perfection?

Hey @cnye9 ! I used the compression machine, if that’s what you mean.

Spain thanks you for your kind compliments!

Hi Marta,

Hello from USA! I love Spain by the way :).

I’m curious about what type of machine you had used here? Can you provide some pictures of it.

I have access to a bunch of polystyrene, and would love to create something similar to what you have here!

Thank you!

Thank you both @davehakkens and @jegor-m !! Looking forward to see your experiments!


Thank you, @gujonon!
We are about to start experimenting with PS and your experiments are quite valuable, we appreciate them a lot.

Awesome update @gujonon!! Last image = 👌

And… ¡here are the results of my little experiment! As you can see, recycled polystyrene can get quite transparent. The tiny spots are mainly air bubbles or other plastics that got mixed while shredding the material.

From 50% down the difference between tiles it’s almost non-existent. There’s more space to play between 100% and 50%.

At the end I got a nice transparent tile. Tomorrow I’ll upload the different results I got mixing it with different amounts of black.

Polishing is where I struggled the most. Since I used the compression machine and I put pressure by hand after melting I had little holes and gaps all over the surface. Those gaps got filled with the polishing liquid I was using, covering the whole surface with tiny white spots.

There’s two options to solve this problem:

1. Finding a transparent product.
2. Polishing and using a toothbrush afterwards to remove the white spots and polishing by hand. It kinda works with the big holes, but you won’t get rid of the small ones.