Frenchy shredder on a budget

Hello everyone, I’m Sylvain, french mechanical engineer reconverted in my  own local phone/computer repair shop.

It’s been years since I was looking for starting my own PP project and I finally start building the shredder.

My first goal was to do everything myself as I am not so bad with my hands^^ but after looking for laser cutting suppliers for a good 3/4 months, I decided to look for a ready to start shredder.
Thanks to Repair Café Pays de Meaux/AC, I managed to get one for a really good price.

As everyone on this forum, the quest for a cheap and powerful motor wasn’t a success. So I decided to try to do  va Frankenstein version with a broken cement mixer I had laying around. The motor was ok, only the main bearing was down. This motor is 0,85kW at 2650rpm… Too quick and way too light for my shredder but it has a 1 to 8 ich pulley reduction and I had a motorbike chain and sprockets I’m my garage that can add an other 1 to 4 reduction ratio. After using my relationship to get a axle machined to fit my sprocket on, I just need to build a support for my shredder and connect everything together.
I made a pretty standard welded frame with bolted intermediate frames to allow some leveling. Added a old piece of countertop and it was done.

But as I was expecting, my moto is to weak to shred correctly, I can shred some plastic bottles without the lid and bottom and it’s better if I cut them in half…

I need to find something to put a better motor I think.

If you have ideas of questions fell free to answer/post them below

Nice work.  I just ordered some parts from the Bazar myself for €425 (about $490 US) because the folks are in the same state as where I live.  My stepdad has a few air compressor motors that we’re going to try out to see how well they’ll perform.  It should shred well enough with the exception maybe of thicker plastic.

If you’re looking for a modest upgrade, check locally to see if anyone has a damaged air compressor they wish to discard.  Once we’re able to try ours I’ll definitely capture some footage and/or images to post.

This engine is 2600W but with a working time of 60%. The shaft speed is 40 RPM. I put 2 groves SPA pulley with 100mm diameter.

But I think i quite too slow now, I still block on bottle head…
for now, I will keep it like that, I will do some cosmetic/safety add like a desk and improuve cooling of the motor, and start to work on other machines (injection ;-))

An other set of pictures :

Hello everyone,
Sorry for been off for so long. I was busy at the office.
I have found a new engine, somebody had a broken branch schredder (the blades were missing) for 10€, it wasn’t risky, after striping it to the bear engine, it seams that I could not connect the shredder and the new engine directly, so I ordered some pulley to connect them.
Here are some picture I take along the project :

i am not sure i fully understand, we print PET as is, into a new shape; not sure it’s covered by the ‘definition’ of recycling per-se, 100%. but yes guys, we need a FAQ and guide for PET, that’s for sure. i know of lots of users sitting on that stuff in tons, most users buying the machines come up with : ‘i want the kids bring their PET bottles and …’. we have currently no recommendation to process PET with the PP machines (‘compression’ machine is a problem, safety and throughout vise). so we’re left with the other materials which are easier to process.

@donald exactly 😀

let me know how your experiments work out 😀

So @imuh :

Virgin Plastic: 0 additives

Recycling them won’t add any (except possible contaminations/heat degradation), so they remain virgin, as long as you keep them clean/pure.


Just checking, because I actually have access to quite some pallet wrap (not saying it is virgin, but it could be 😉 )

oh , and concerning the “100% recyclable” written on the bottles, welcome to the green washing 😀
let’s take the example of a PET bottle. Recycling industries have to take care of tons & tons of plastic at a time. So in order to be effective, industries specialize their process for a certain type of flux.

PET bottles is a flux of it’s own. Though on the PET bottle it is written 100% recyclable. The only part that interests thesaid industry is just the PET. The lid isn’t PET, the wrapping (with writings & info) is not PET, the glue or ink is not PET. Though it is said on the bottle that it is 100% recyclable, the specialzed industries who recycle them will never do 100% 🙁

cheers !

it seems i wasn’t clear enough :stuck_out_tongue:
So… how is a plastic made ? again & again copy paste (sorry for the ones who read this before)”Plastics… so what is a plastic ? A plastic is : polymer + additives

The polymer can be Polyethylene (PE), Polypropylene (PP) etc… each polymer has it’s own properties (density, clearness, softness etc…)

Additives on the other hand will give extra properties to the plastic. The types of additives are VERY wide, can be to add uv-resistance, strength, make it easier to inject, cheaper to produce, flame resistant, etc…

Each additive (at least in europe) is more or less regulated into big categories of products, the most strict category being “food grade”; the legislation only permits industries to select additives through their list (1000+ possible additives)

Also, additives always migrate, meaning they get out of the plastics through time, heat, contact… and each additive has a treshold which should not be exceeded (measurements are based on the usage of the product; single use plastic = 1 time use migration treshold measurement)

Soooo when you are putting one type of plastic to melt; there are different additives which may react to each other, and your long lasting “food grade” recycled plastic product will slowly but surely migrate its different additives to the consumer To limit this effect i would recommend you to have an effective ‘sourcing’; meaning trying a specific product at a time and, if it goes well, put it on a green list; otherwise, red…

(What i wrote is just based on the research of have been doing the past year on the subject, making mistakes, learning from them and searching more & more, which might not be the case of everyone launching PP projects _to answer to the “food-grade” recycled products on the bazar_ ; if any polymer-specialist would mind adding their intel on the subject… )”

PET Bottles contain additives (a recent new member of pp sartrouville used to design PET bottles for a Danone and gave me that info)
Here is the french IRSN data sheet concerning PET

It is VERY rare to find products who have 0 additives, but there are some…
for example some pallet wrap has 0 additive, i actively recommend you to give it a try !

I’ve read the post to quickly, @imuh, it’s sure that additive component to plastic are a nightmare to recycle them, but I think PET bottle have no additive as they still are clear transparent and it’s written 100% recyclable on the label…

For the vacuum forming machine, it’s a great idea, I’ve seen a lot of youtube video on how to build one but each lime they use brand new material from the store, I haven’t thought of using plastic bottle as vacuum forming material…

Great topic to follow. Thanks


I think @imuh means virgin products like in ‘virgin oil’, meaning no chemical additives (had to also look it up myself). These can also be recycled.


Re: flattening the bottles: Gonna try doing just that with a heat press, but for a different purpose ( Reusing Plastic for Vacuum Forming ).

I will check out the Kings!

@msnmck, It seams than US compressor are differently build than french ones, in my case, smalls compressor for home use are in single phase 230V but have very small engine, like 1/2HP and professional compressor are mostly on tri phased current. I have one small and one big semi pro one and it’s what they are…
For the cable, it seams inevitable that you had to cut them at one place, some knowledge of electricity connection is a must when you do DIY projects.
For my PET sourcing, I drink a lot of water in bottle myself and I started to talk about my project around me so they give me their too. The solution I have found so far is using tin snaps to cut the lid off and slice the bottle in half to remove the bottom part, i will do some pictures at noon.
I want to use first injection molds to recycle plastic and I hope that PET will be compatible with it…

@imuh, I am a bit lost, on PP poster it says that PET is melting around 280°C, are you sure of that?

though PET is the polymer which requires the highest temperature to melt, it’s stil more than feasable with a regular oven (you need around 200°

I am aware that working with virgin product is easier and more forgiving but my goal is to recycle so I will not buy raw material to experiment with…
But thanks for the links and the informations.


I would like to test a combination of a bottle cutter and thread cutter to create pet flakes, instead of directly shredding them.

I had the same kind of idea, right now I’m doing it manualy with a tin snap but I was thinking of putting a boxcutter blade on a jig and remove the lid and bottom more efficiently. I have try to flatten them out with a hammer but the thickness problem is still there for me.
I would love to see someone do a test with freeze bottles, we could ask The King Of Random to try that for us^^

though PET is the polymer which requires the highest temperature to melt, it’s stil more than feasable with a regular oven (you need around 200°)
The tricky part about experimenting PET is that it can be very frustrating.

Indeed, PET is very sensitive to 2 types of degradations : thermodegradation (when put at too high temp, or too long at high temp) and hydrdegradation (which will occur if there is water/humidity)

Also, keep in mind that additives can have a impact on the recyclability of a plastic product. In such, i would recommend to start experimenting with virgin plastic products.


Pallet wrap can be found in virgin LLDPE
here is an example of a virgin PP product :
and here is an example of a virgin PS Cristal product :

The aim of that is to “feel” how a polymer reacts to melting/remoulding. It should help you out a lot to figure out later when plastic products are no-go for recycling

please let me know if you have any issues understanding this part 🙂


I’ve got quite the reverse problem in the Netherlands as most (regular) PET has a deposit on it, making it kinda expensive to experiment.

Doesn’t help we have basically Perrier/Chaudfontaine coming out of our taps, so no real need for massive ammounts of water bottles.

But maybe I’m just overlooking an obvious source.


I would like to test a combination of a bottle cutter and thread cutter to create pet flakes, instead of directly shredding them.

The bottoms and necks I would try to ‘brute force’ with the proverbial sledgehammer.

Maybe freezing them first, if need be.

You’re welcome to beat me to these experiments, as you do seem to have an abundance of PET.

But maybe this should be another Topic…


As for the PET, since I started collecting for recycling that has been the single largest quantity of plastic I have received by a large margin.  I decided to cut up a gallon sized water jug with a pair of scissors just to see what I was in for. You weren’t kidding about the difficulties. Scissors, shears and even a box cutter could not penetrate the base or the ring.  It took nearly an hour for a small amount of plastic in the end.  And I’ve been reading topics in the forums to see if there is a more reasonable way to melt at such a high temperature because and oven seems like it would be a huge waste electricity, even for testing.
Great topic you’ve made.  Hopefully we all get to learn something from it.


I think you are talking about a triphased engine from an air compressor, I want to have a monophased engine to be able to shred every were, here in France we are a very view to have triphased curent… but I will look there to see what I can get.

The two compressor motors I pulled today are single phase. It turns out that the biggest issue is that the manufacturers misrepresent their operating power.  Both are 120v, 15 amp motors but are called “5 HP” (3.72 kW) motors on the compressors themselves.  Actually, another small issue is that the cables had to be cut since the power cords were connected to pressure gauges and not directly to the motors.
Actually, a third issue is that it probably sounds like I understood a single thing I just wrote 😅

Hello @imuh,


We should keep the English to let the other read this more easily ^^.

Thanks for the sourcing, I’m on everyday looking for big motor with reducer and I never thing of searching a shredder…
I will investigate that way in case of mine do not work with other plastics.

Thanks mate

Hello @sylvain07 !

Here is how a couple other french folks sourced their shredder motor :

“silent” branch schredder seem to have to right motor specs, 1200rpm already reduced to around 70rpm, monophased, and you get to keep the “on/off” and “back/forward” buttons !

Here is an example of thesaid “silent” branch schredder; i emphasize the “silent” because it is how they name the machines which are already reduced.

hope it helps !
Cheers !

@s2019, I will do some test on different material and thickness this weekend, I will post it there next week I think.

Looking to the PP melting temperature poster, PET seams to be the highest melting temperature…
I will see if I can switch to an other material after my testings.