Dec 30

Plastic recycling

From time to time I need a big lump of plastic to construct something in my workshop.  Suitable pieces are usually either difficult to find or expensive, so I’ve been looking for alternatives which preferably use material which would otherwise go to landfill.

After watching this video about recycling HDPE (#2) plastic, I bought a toaster oven and gave it a try.

Step 1: collect (and wash) milk bottles:


Step 2: remove labels (this is easier if you first heat the labels using a hair dryer):


Step 3: cut into strips and pack tightly into soup cans.  Bake in toaster oven at 190C until molten:


Step 4: allow to cool, and cut soup can off the slug:


While this worked, it was a little too labour-intensive for my liking. I tried using heavier-gauge HDPE plastic from buckets and water jugs, but unfortunately these will only soften to the consistency of chewing gum, and need some type of press to squeeze them into the desired shape.

After looking around for a while I found these polypropylene (#5) plastic tubes, which were originally the cores from rolls of paper:


Cutting these into soup-can-sized lengths is very quick, at which point they can be slit lengthwise and coiled up to fit inside each other inside the can.  As an added bonus, this plastic “flows” much more easily once it has melted:


Once again it’s usually necessary to cut the can away once the slug has cooled:


Lately I’ve been rebuilding a 54″ lawnmower cutting deck, and I needed to fashion some new anti-scalp rollers for the front and rear.  These need to be about 100 x 250mm cylinders, and since the deck belongs to a John Deere the ideal colour scheme is green/yellow:


A little searching at my local recycling centre turned up a cracked and broken children’s sandpit, made from polypropylene:


As usual, this was cut into strips and packed into tin cans (this time 1.2kg dog food cans, to get the right diameter and length):


This particular batch of plastic had enough shrinkage to allow easy removal of one of the slugs from the can once it had cooled (I still needed to cut the second can off:


The blue polypropylene plastic in this image came from several electrical cable spools.  In this case I’m using some old teflon-coated cookware as the moulds:


Unfortunately I still needed to cut away the round pan once the plastic had cooled, so now I line any pans that I want to recycle with baking paper before packing them with plastic strips.


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