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Inexpensive way to grind plastic bottles? Answered

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

Discussions

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BrandonM276

9 months ago

I think there are legal issues.
That’s why you don’t see them
for sale,as a bottle shredder.
I have the problem of plastic to
and have a design to built
a safe plastic shredder.

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BrianW244

1 year ago

I am sure that this could be mechanised .

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BrianW244

1 year ago

Has anyone tried using an old style paper guillotine, I can remember the one we had in junior school it was huge (everything is huge when you are five years old if I can find a photo I will post it later

Tues 10-3-17 1:55 p.m.

Booga Booga from the Wizard of Los Alamos!

I cut up bottles all the time.

Method 1: Take a soldering iron and make a tip for the soldering iron using stripped Romex wire. Hammer the end of the soldering iron tip flat on a bench vise. The soldering iron can be used for slicing up plastic bottles.

Method 2: take a pair of tin snips and cut the bottle up into 1/4-inch wide bands. The bands can be cross-cut to make 1/4-inch by 1/4-inch chips.

When plastic is manufactured, it is heated, extruded and then cut off to form small pellets. I would start looking at vendors who make these type of systems to determine if you might be able to make a low-cost version of such a system.

Please wear appropriate Personal Protective Equipment (PPE) - Long sleeve shirt, eye protection, apron, gloves if you embark on such an effort.

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elkaddalek

1 year ago

I've seen meany ways to grind/shred plastic.(personal reserch :D) the cons & prose of each one,(I think).

Paper Grinder, have to adapt a drill to metal shredder blades,cuts into length long pieces, not durable enough to chop hard/thick plastic( no pro )

Meat Grinder, have to mount it on a solid table, grinds into small pieces, have to cut up the plastic before inserting into the grinder, produces alot of static & the plastic sticks together when in comes out.

Blender, have to cut the plastic into small pieces before blending, if it's not a high quality blender it will just spin the plastic around & you can only blend small amounts at a time.

Lawn Mower, big, gas powered, alot of welding & wood building for the frame, possible limb loss hazard.

Wood Chipper, works good, small plastic chips, possible limb loss.

Laser Cut Metal Plastic Shredder Kit, works as good as any other industrial plastic shredder, lot of welding, wood work, lathe experience to make the shaft or other pieces, need a laser metal cuter or someone who has one to cut the blades & other metal pieces.

(Personal Thought/Idea) can thick wood blades or a wood wheels with metal ground sharp blades work?

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Kyu TeeL

1 year ago

https://preciousplastic.com/en/videos/build/shredder/

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3gghead

2 years 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..

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Toga_Dan

2 years ago

liquid N

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chrisd335

2 years ago

hi

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...

first

cut the bottles into string here is a possible method

https://www.instructables.com/id/DIY-Plastic-String...

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

http://www.thingiverse.com/thing:288465

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

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critical1

2 years ago

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

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MichaelC501

2 years ago

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.

http://preciousplastic.com/

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SimonO23MichaelC501

Reply 2 years ago

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? http://filamaker.eu/

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SethJ4

2 years 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!

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ochSethJ4

Reply 2 years 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...

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pkerry1

6 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.
http://tinyurl.com/8kypzp4

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PhilipTKpkerry1

Reply 3 years ago

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

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calmorganpkerry1

Reply 5 years ago

I would like to know how to contact the company or one of their representatives. This looks like something I can use.

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NeuroPulse

3 years 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!

https://www.instructables.com/id/Plastic-shredder-for-making-3D-printer-filament/?comments=all#CLRH3L9IAXRIEI6

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jasper868

3 years ago

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

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dfriedel2

4 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.

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jdoubleday

4 years ago

what about a mulcher?

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rjeblogue

4 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. saveoceanlife.org/?p=251

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p11paul

4 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.

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snk24

5 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 http://watermarked.cutcaster.com/902008588-Metal-grater-texture.jpg) 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

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zubb

5 years ago

i think simplest way - take 10..20 115mm wood saws, and stack them on 2 opposing-rotating shafts.

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Josehf Murchison

5 years ago

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.

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bnajbert

5 years ago

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NeuroPulse

5 years ago

How to make you own desktop grinder...

http://www.youtube.com/watch?v=K1a1QB4h1oA&sns=em

Plastic filament extruder for 3D printers...

http://www.kickstarter.com/projects/rocknail/filabot-plastic-filament-maker

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onrust

5 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.
http://youtu.be/CYnafV0aZgo

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Phuddy

5 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?

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Kidsvoice

5 years ago

HI, MY NAME IS PHIL DESIR, I'M SEEKING A WAY TO HELP AN ORPHANAGE YOUNG ADULTS IN HAITI TO GRIND SOME OF THEIR OWN PET PLASTIC BOTTLES SO THAT THEY COULD SALE TO THE WORLDWIDE MARKET TO SUSTAIN THEIR SCHOOL. DO SOMEONE KNOW HOW ? OR CAN HELP?
CONTACT US IF PLEASED; kIDSVOICE@NETZERO.NET

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superpants

6 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.

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hopelesslyfolksuperpants

Reply 6 years ago

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.

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shilts

6 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...

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zieakshilts

Reply 6 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.

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Toga_Dan

6 years ago

Melt the bottles, remove bubbles by using a vacuum pump, extrude it through holes like a garlic press, cut strands to length.

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Jay006

6 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:
http://www.youtube.com/watch?v=btf5YT-VQTM
http://www.youtube.com/watch?v=ow-oUyaTgoo

I have just made a homemade plastic extruder ( https://www.instructables.com/id/Plastic-injection-molding-and-extruding/ ) so shredding household plastics was going to be my next project.

Good luck.

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kenyonsandyJay006

Reply 6 years ago

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. kenyon.sandy@gmail.com

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gcouger

6 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.

gc

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killerjackalope

6 years ago

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...

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The Ideanator

8 years ago

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)

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Weissensteinburg

8 years ago

Maybe a food processor? You should be able to find a cheap one at a garage sale.

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zascecs

8 years ago

How about freezing the bottles and then smashing them with a hammer?

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mattslat

8 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 http://www.jordanreductionsolutions.com/blog/recycling-plastic-bottles

And the other is our Plastic Grinder web page which details all the specs about our plastic grinding machine. You can see it at: http://www.jordanreductionsolutions.com/plastic-grinder.html

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. 

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RedneckEngineer

8 years ago

Just another thought.  Was looking at the https://www.instructables.com/community/Plastic-Soda-Bottle-Prosthesis/
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????

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sharlstonRedneckEngineer

Reply 8 years ago

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