Inexpensive way to grind plastic bottles?

Greetings, I am looking for an inexpensive way to grind individual plastic bottles into particles for easy melting in molds. I tried a blender. It just scrapes it very loudly and burns it. It doesn't break it up. Thanks

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Kyu TeeL8 months ago

3gghead1 year ago

What sort of volume are you thinking? You could use a lathe with a chuck that makes use of the threads for the cap. Might require a cotter-pin, depending on direction of turn and/or the bottle's threads. For higher volume, you might want to attach some saw blades to the shaft of a high-torque motor then build a feed & exhaust system around that. Depending on the blade-spacing, you could shred HDPE to dust if that's what is needed (fi, heating pre-filled molds). For best results, air-cool the blades at the very least. At the same motor speed, smaller blades will heat-up faster larger blades and may begin to melt the bottles which would make a mess in the collection bin.

Just some 'left-field' ideas..

Toga_Dan1 year ago

liquid N

chrisd3351 year ago


this is an old thread, but I think I have a pretty easy way to do it at home - it is a 2 step process and this will only work with bottles - like the water bottles that are everywhere...


cut the bottles into string here is a possible method

Then grind up the string with something like this- it is a filiment pellitizer.

If you want to throw a whole bottle into the grinder - it will cost lots of $$ - but if you reduce the size of the material to only a few mm wide, then it gets much easier. This should get you to a pelletized PET bottle plastic you can then use to make filiment from pretty cheaply and close the loop between plastic junk and filiment

critical11 year ago

Hmm I wouldf have thought sink garbage disposal unit would do a good job!

I know this is a very old post, but those of you whom are still following the thread and have been waiting all this time, I might have found something. The guy on this website makes the grinder, compressor, extruder, and injector! All of it is DIY and he has the plans available FOR FREE. It'll still set you back a few hundred dollars, but the ROI is worth it once you're pillaging the neighborhood recycling bins for all their plastic. Once I find a metal working shop in my area, I'm definitely going to at least start shredding the plastic for volume reduction and long term storage. Then I've got to decide if I'm building up or pyrolyzing down the shredded treasure.

Hi, I'm with you on the long term storage bit.. Seems the first sensible thing to do before spending more time/energy converting shredded material into something new. Did you get anywhere with the precious plastic machines? I'm looking for a machine of some sort that I could use to shred plastic bottles directly on the beach. Have you seen these guys?

SethJ41 year ago

I sent the files for the shredder part only for a quote to be water jet cut, came back with a quote of $889 NZD + GST (15%). Not really DIY and not really affordable at all!

och SethJ41 year ago

Try a plasma cutter instead, it should be cheaper than a water jet, but yes, the project is not really inexpensive. I'm being charged $500 USD to cut the pieces with plasma here in Costa Rica, plus the cost of the motor, reductor, etc...

pkerry14 years ago
I think I have the machine you folks are looking for. Take a look at this YouTube video which shows machine that shreds plastic bottles and aluminum cans. It is an Italian-made machine (and thus an Italian speaking video). I have been introduced to the company that wants to bring it to the U.S. I am interested to get feedback on this, including whether there would be demand for home-use for this (with an appropriate machine size and price point of course). I believe that there would be a demand for larger commercial uses. I would jump to around 1:30 in the video where they start showing the machine. Thanks and I look forward to any comments.

Hi! I'm very much interested in this machine. Is there a way to contact the Italian supplier? Or a reseller?

I would like to know how to contact the company or one of their representatives. This looks like something I can use.
NeuroPulse (author) 1 year ago

5 years since OP and still no affordable home shredder exists. Here is a new design idea. A contest is needed for s plastic shredder! It would rvolutionize 3D printing!

jasper8682 years ago

Office paper, shredder cd/dvd. High in one can chew up CD's into little bits.

dfriedel23 years ago

If I used circular saw blades on perhaps a 1/2 in drill motor the speed would need to be slow; To not melt the plastic and to be safe.

jdoubleday3 years ago

what about a mulcher?

rjeblogue3 years ago

you gotta check out this site. these guys shredded TONS of bottles. They staggered saw blades on an arbor and enclosed it with a housing and a hopper powered with an electric motor. I have been wanting a machine to recycle plastic to make filament for my 3d printer and this is an inexpensive tested machine from the looks of it.

p11paul3 years ago
Use an old type spiral bladed lawn mower. Place your plastic bottle on the grass and it will shred it in no time at all.
snk243 years ago
If someone still follow this post and have an old blender you can modify a plastic jar and the blades, instead of blades you make a rotating grinder (with small holes like the ones for cheese with an extended shaft so you have space below the grinder for the chips, you can even open a hole in one side and add a tilted plate for the chips to go out to some recipent. The tricky part is the rotating grinder, at that speed i am sure you can grind anything, but it's needed to buy or make one and fit it in the jar so it wont get out or bend with the applied pressure. And you might also get strips instead chips XD
zubb4 years ago
i think simplest way - take 10..20 115mm wood saws, and stack them on 2 opposing-rotating shafts.
I worked in a sponge rubber factory one summer when I was in high school. To recycle the scraps we ran the sponge rubber through a special chunking machine the chunks were then mixed with binders, packed in a mold, steamed to set the binder, and pealed to make under padding.

The chunking machine was, (drum roll please)

A stack of spinning coarse saw blades with spacers between the blades.

You could do the same with fine carbide toothed saw blades with washers as spacers mounted on a shaft and driven with a motor and pulley.
bnajbert4 years ago
NeuroPulse (author) 4 years ago
How to make you own desktop grinder...

Plastic filament extruder for 3D printers...
onrust4 years ago
Here is some food for thought. How about an electric wood chipper. This video shows them grinding just the caps but I think it could do bottles as well.
Phuddy4 years ago
I have been looking at this myself as I work for a company who produce plastic components etc. We get a number of returned items that we cannot re sell for health and safety resins. I was thinking about shredding the plastic and recycling this. The Plastic we use is polycarbonate. I think I have an idea about this problem though. How about converting an old Clothes Mangle and using something like the Cams from an old engine? Reshape the cams slightly so they are similar to the ones you see in the youtube videos etc and then push the plastic through the mangle? I think you'd need to weight the top of this and make a few mods but I think this could work? Does anyone have an old Clothes Mangle they would like to try and convert?
Kidsvoice4 years ago
superpants5 years ago
When I used to work in a lab doing polymer development, we used to use a small coffee grinder for reducing pellet sizes. They wouldn't last forever, and needed relatively small piece feed in, but worked pretty effectively.
I am trying to find a small grinder for reducing pellets size. What kind of coffee grinder did you use? Burr, blade, hand crank or electric? I've also looked into small grain mills. Any thoughts appreciated.
shilts5 years ago
I just started thinking about this. The only problem with my idea is the opening. You would have to cut the bottles smaller to fit but it should work. Use a paper shredder that is capable of destroying credit cards or CD's. There are plenty of low cost paper shredders that have the capability of doing this, I don't know how long they would be good for, especially if you were doing it constantly, but then again, breaking the thing open and replacing the motor shouldn't be too hard...
zieak shilts4 years ago
That's a good idea. If you removed the tops and bottoms and cut along the length of the bottle you would have a sheet that could be fed into the shredder.
Toga_Dan4 years ago
Melt the bottles, remove bubbles by using a vacuum pump, extrude it through holes like a garlic press, cut strands to length.
Jay0065 years ago
You cannot assume to grind plastic in the same way you grind other materials. Plastic has different properties.

If high speeds are used to cut plastics, generally it will bounce or melt. The only way to grind it is by using a slow speed 'tearer'. Where the slow, strong force forces the plastic to tear.

Some good examples of this are:

I have just made a homemade plastic extruder ( ) so shredding household plastics was going to be my next project.

Good luck.
A home plastic bottle shredder is a great idea and one which I would use and sell through my new business, SandEco, LLC. Please keep me abreast of your progress! Also, find SandEco on Facebook. Thanks, Ken.
gcouger5 years ago
How about 2 rows of circular saw baldes with carbide tips both rotating toward the center. Every other blade going a different way.

You might be able to modify an electric wood chipper to do it, they're adjustable anyway - you'd simply need to get the cut plate the right distance from the big cog - even if it jams they're reversible...

I was working on a badly jammed up one last week and they're very simple and provide the cutting forces needed, though a blade change may be needed to be effective...
Perhaps a ball mill might be nice. (hint: use a rock tumbler and steel ball beings (I've found bolts work nice too) like this guy)
But thats if you don't mind slow production
Maybe a food processor? You should be able to find a cheap one at a garage sale.
zascecs7 years ago
How about freezing the bottles and then smashing them with a hammer?
mattslat7 years ago
I'd like to point out two resources that we have on our web site that deal directly with grinding plastic bottles. One is a blog post at about "Recycling Plastic Bottles with a Shredder" at

And the other is our Plastic Grinder web page which details all the specs about our plastic grinding machine. You can see it at:

We manufacture all the equipment in Birmingham, Alabama, and offer free testing and demos at our manufacturing plant. You can reach us at the contact info on the web site if you need more help or info. 
NeuroPulse (author) 7 years ago
Over a year later and still searching.

The most promising thing I have found is a wood chipper like this

But what is really needed is a small version of expensive industrial grinders.

These guys look like they might be working on one.
Just another thought.  Was looking at the
ible and video and it hit me. My father used to work in a bottle makeing company where they made 2L and 3L bottles and I remember he use to bring home the bottles before they were blown up to size.  They were like 6 inches long and very thick test tubes.  Once they were heated and air blown in to make them to size the only part that didn't change was the screw on top part. Part of the problem on grinding the bottles is they bend and flex while attempting to grind them (at least thats what everyone here is saying).  They said in the video that the plastic thickens as it shrinks, thus becoming thicker and stronger!  Take the bottles and shrink them down and they would be easyer to grind up.   So simple it's almost scary!  Anyway long forgottem memorys aside this could be the answer we are all looking for.  Anyone with a heat gun willing to give it a try and report back????
my dad works at a bottle working plnt aswell i use the bottles for holding liquids and using them as pressure tanks by gluieng the tiop down and put a valve on top
Maybe some kind of meat shredder.
Longwell7 years ago
I've been working on the same idea.   The plastic from milk bottles fuses beautifully at low temp on raw plaster mold.  tried blender with water--no good, but the blades were very worn from grinding glass for another project.  I can't believe none of you guys has solved this very urgent problem.   I like the idea of using circular saw blades.  I have a huge collection of old worn out ones.  what about putting dozens of them on a single shaft, then using that assembly to grind / chip away at the bottles as they are trapped against the blades by a tapered chamber ?

What about coffee grinders?  (blade type)?
i like this idea the best (the circ saw plan), basically making a home made wood chipper at that point
onrust7 years ago
I found this on youtube.  It is a company called Patriot Products ant they have a good solution to shedding plastic with a 110V leaf chipper.   Unfortunately it is not cheap.  It is good food for thought and used leaf chippers can be found.
Just a thought that hit me.  Think along the lines of a cheese grater.  A round drum with sharpened holes that turns and chews up the plastic as it is forced onto the drum.  If this was made big enough you could really crank out the chipped plastic fast.
I wonder what will happen if u stick it in the freezer, or you make a weird table that vibrates with some very sharp stuff in it. Vibrate vigorously until particlized. How about sanding it? 
Try using a shredder thats capable of blending Credit cards !

When the blades go dull cut a piece of aluminum foil to a4 size shred that and itll sharpen your blades
lemonie8 years ago
An inexpensive way is going to be a hard work way. Unless you can find a heavy-duty shredder for nothing?

all home use paper shredders I have seen on the market, will only last so long, for a lot of paper, you buy a big office shredder

What about a CD shredder? Same trouble, they are only meant for 1-2 CDs a day or so, not a stack of plastic bottles.

But, there are firms that shred confidential documents, their customers fill locked bins with confidential documents via posting slots, then these bins get tipped into big shredders, and the product coming out, is sold for packaging purposes.

PS, the CIA has hundreds of sacks of shredded paper, recovered from the offices of the East German Secret Police, whom at the last minute, shredded all their files on their under cover agents, and sleeper agents.

The CIA is working on computer software, to use to put all the shredded paper back together into original documents.

Nothing and nobody escapes the CIA for long!!!!!
Yes I've heard of that shredded paper project, I might go looking for it...

PKM8 years ago
Cut the cylindrical part open and feed into a crosscut shredder? Use a different type of blender or a meat grinder? You could also try leaving the bottles in the freezer to make them more brittle, or putting them in boiling water for a bit to make them softer- either one might help or might not, try both.
Almost right,  get a Thermos jug of liquid nitrogen, dip the plastic in, and drop it onto a hard surface, unlike a freezer making them stiff and flexible, liquid nitrogen  makes plastic TOTALLY brittle.

Source of a small amount to experiment with? Medical Doctors in large practices get a flask full to wart removal, they put a drop in, and freeze the wart to death. In NZ, my doctor gets a flask once a week, and all wart removals are done that day.

However, take your plastic for experimenting to the doctor, you will never get the ligual nigoren hoime with out that flask, there is a name for the flask.

However, I dont think you can afford to buy the stuff, but the flask will be on loan to you, from the supplier.
correction, stiff and IN-flexible
LinuxH4x0r8 years ago
Is this for extremely large quantities in industrial use, or for home? For industrial they make granulators that grind it into pellets.
forget cutting up plastic bottles, go look for a plastic recycler with a granulating machine and buy a sack full'

But In NZ, all our plastic bottles get compressed into shipping containers and sent off to China.

We were even told, dont bother washing the empty milk bottles, China has never moaned about the smell when they process the plastic
CameronSS8 years ago
A blender comes to mind.
You will note above, I worked in a cannery, we had super large blenders, so I can tell you, its very likely the plastic will be thrown around by the blades, but not actually cut.

Sometimes, we froze soft vegetables before putting them thru a large frozen meat mincer (or grinder in the USA) but I dont think any mincer can handle plastic bottles even with our cutting feed worm.

i.e, blocks of frozen meat off cuts in, 30-seconds later, cooked meat comes out, ready for canning, === corned beef.

A week on that production line, you will be off meat pies for life.
I like this one.
drhoff7 years ago
 I have been thinking about this for a while too. One idea that just came to me is using a power saw to keep cutting it up until you have a pile of plastic sawdust.
I got a Dewalt table saw, and experience with other saws, you will find the plastic bends away rather than cut narrow strips, and the plastic will quickly gum up the works, if any gets into the motor, or gear box, (the weak point on my otherwise great saw) it could prove costly.