Experiment #5 – Mixed plastics

I collected a bunch of bottle caps from the Clean-up Burley Griffin Day and decided to try another Plastic Experiment with what proved to be mixed plastics i.e. multiple plastic types.

They came from a range of bottles and some were really old. So, I really didn’t know what kinds of plastic they were made of. However, since all of my previous experiments seem to melt fairly consistently, I thought I should try doing something with this plastic too, betting that an old Coke bottle lid would be made of something similar to milk bottles.

But I was wrong. I found that the usual 180C melting temperature for HDPE was only slightly melting most of the other pieces. So, I turned up the temperature and hoped for the best.

Unfortunately, the results were mostly of burned HDPE #2 and half melted other plastic(s) – maybe PP #5. Furthermore, the higher temperatures actually melted the silicon mould too, resulting to it sticking to the melted plastic and destroying my mould.

Burned plastic and moulds
My burned moulds

This Plastic Experiment is a really good example of why recycling plastics is so hard when there are so many variations of plastic with different properties including melting point – creating mixed plastics to be sorted. I still have a few bottle caps left and may try again, but first I have to order a new mould. Sigh…

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Tammy Ven Dange

Purpose Driven Entrepreneur Be kind to animals and mother nature!

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