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How do you sort unknown plastics into types?

This topic contains 4 replies, has 5 voices, and was last updated by  Dayana 1 year ago.

Steve upcycletaranakinz

How do you sort unknown plastics into types?

15/11/2018 at 22:18

Hey all!

We are a group of teenagers from Taranaki, New Zealand called the Trashformers. The aim of our project is to be able to recycle degraded ocean plastics into useful items (like phone cases or flower pots). We are also going to run experiments to test the durability of the plastics once they have been melted in the machines.

We are currently working on building the shredder and extruder machines from the Precious Plastics website, to melt and mould the plastic we collect.

We are all keen to better our environment, marine environments in particular, and thought a great place to start would be to make use of the waste collected on beach clean ups.

Just recently, we have run into the problem of sorting and grading plastics collected on beach cleans, so that they can be melted at the correct temperature and will be made of the same plastic. We are having a bit of trouble figuring out which plastics and which number when they do not specify it.

How have you overcome this? In particular, we are looking to start working with numbers 2 and 5. Is there an easy way to identify these that you have come across?

Thank you for your time!
Taranaki Trashformers group ♻

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19/11/2018 at 10:10

Hey Trashformers if you need any help feel free to get hold of me.  My names Mark I live in Otorohanga and I build machines my number is 02102298966 also add yourself to the Precious Plastics NZ Facebook page and share your message 🙂

02/01/2019 at 20:15

Toutes les infos ce trouvent dans le kit de téléchargement sur le site.
C’est bien expliqué et le tableau de traitement aussi.
Bonne journée à vous et bonne et heure Année

05/01/2019 at 09:40

Here in the Upper Midwest,  aka Iowa. 2-5 is taken everywhere.  6 aka Polystyrene,  the most recyclable, least profitable is Landfill.  Everything else is a 7 or unmarked treated as 7 = “stuff”  IDK where 1 went? Paper laminated cartons, Soy, Almond etc & Tofu are recyclable!

01/08/2019 at 19:21

Hey upcycletaranakinz ! I am also investigating this question – I will be doing a waste/plastic audit for some beaches in Mexico later this month. I found some tool kits created by BreakFreeFromPlastic.org that were helpful. Although they mainly focus on “Brand Auditing” the diagrams they’ve put together seem useful.

Here are a few links:

Type of Product
Audit Form
Waste Audit Form

Typically certain types of items are made from certain types of plastic (e.g. food containers usually from #5, rubbery items typically are PVC) and thus sometimes assumptions can be made by categorizing objects.


One question I’m also looking to answer is how to identify plastic types from objects that are no longer in their original form. I will try to utilize some techniques that were outlined by PP here in this video: https://www.youtube.com/watch?v=fsqLJNyrVss


Let us know if you’ve learned any new techniques from your beach clean ups! I’m sure there are many people curious to know.

Good luck!

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