Shredding plastic with a grinder

Hi guys,

sorry if this topic has already been handled, but i could not find it, so i’ll start it myself.

I’m probably going to start some plastic recycling, but by watching a lot (really a lot!) of videos i know there are some things you have to do (or should not do) to get a good result and shredding the plastic is one of them.

However, i’m just going to start a little, so building or buying a shredder is a little bit too much at this moment.
There are a lot of people who tried to build shredders themselves, like hacking a paper shredder or using the kitchen machine but i get the feeling that all of these are not really working without the blades, cut from metal and the use of a proper machine.
So here i am, a bag full of hdpe-bottle lids, thinking about starting. (and doing a lot of other things in the meantime).

Normally i work with wood so i do have a bandsaw, but cutting small lids into smaller parts with something like a bandsaw seems to dangerous.

Well, i’m not in a hurry so i keep looking, but then i saw someone who converted a grinder (something i have) into a shredder.

It looks like something that i could make, and with the necessary safety precautions, i think it could also be save.

Or am i wrong?

Have you ever seen something like this? Experiences? Thoughts? Do or don’t?

And why?



Unfortunately no reactions to my post,
which amazes me a little ’cause i think that almost everyone working with plastic will eventually have to make/get a shredder?

For me making ‘an original with all the blades and motor’ was out-of-scope for now and the alternative seemed doable with the materials I already had, so i decided to give it a try.
The result: 18, Plastic Shredder - YouTube

Feel free to leave comments here, or below the video!



Hi s2019,

Thanks for the link, i will have a look!

And thanks for the advice about fumes, a good one to keep in mind!

With your building skills, an injection machine should be accessible. I used an alternate arbor press design  (unfortunately some of the posts in that thread are missing). If you are going to do the melt and press, be aware of the fume issue.

Hi s2019,

thanks for for your reply!
well, actually you could be right, i’m Just a starter and somewhere I heard that in order to get the best result, you’d better shred them. I haven’t made anything yet, I was only thinking about ways to shred them and looking for people in my neighborhood who might have a shredder.
so thanks for your reply, I will sure give it a try with maybe just cutting it in half.
(I don’t have an extruder/injectionmachine, i’m Just going to melt and press it for starters, I think).

I guess my question is why do you need to shred the bottle caps? Are you extruding them? Are they bigger than the inlet to your injection machine? For a lot of what I do cutting them in half is sufficient. If you look in the Bazar the people pressing clock faces or table tops leave them in one piece for a more interesting look. I use a metal shear, utility knife, or scissors for laundry bottles, caps, etc.

I do like the grinder to blender concept in your video. A more extreme bend on the blades and a plunger to push the caps down may get it to work.