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Shredding plastic with a grinder?

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F. Steenbergen freddeblikjesman

Shredding plastic with a grinder?

01/12/2019 at 18:58

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?



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05/01/2020 at 23:02

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: https://www.youtube.com/watch?v=g0bfGw5liHY

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



05/01/2020 at 23:45

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.

05/01/2020 at 23:58

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).

06/01/2020 at 00:14

With your building skills, an injection machine should be accessible. I used an alternate arbor press design http://onearmy.world/community/forums/topic/portable-desktop-injection-machine/  (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.

06/01/2020 at 13:42

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!

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