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Shredding plastic bottles?

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  • Shredding plastic bottles?

    We have a Pie Shop and we make lots of coffee and sell lots of soft drinks, so consequently we have lots of plastic bottles filling up our bin each week. As rubbish removal rates are climbing rapidly I was thinking that if we could shred the plastic bottles and send them for recycling we would be saving twice!
    Has anyone got any ideas what sort of a machine you would build to shred the plastic bottles?

  • #2
    Have a google for 'Plastic Granulator' to get a better idea.
    Every moulding business has a few of these as we recycle our waste and scrap at source to re-use it again straight away, but they are quite chunky beass and very noisy.

    Basically, we use a powerful slow running motor turning a shaft with 3/4/5/6 guillotine blades, running over a thick (1/2") mesh screen formed to be a little bigger (1/16") radius than the turning blades, with hole sizes for the mesh being around 1/4". The blades are hardened and about 1/2" thick.

    The scrap is fed down a hopper throat and gets mashed between a stationary blade and the rotating blades then out through the mesh screen when they are small enough to re-use in the moulding machine.

    However, we still have to bandsaw large items into smaller chunks, and thin as a plastic bottle is, it would still be too big to feed into this. So perhaps making one is a bit of a tall order.

    But - most drink (soda) bottles are injection-stretch blown from PET, which has a Tg of around 70 deg F IIRC, and if you can get it hotter than this it will shrink in size and distort back to an earlier 'pre-stressed' form, thus making the overall volume smaller. An experiment with your pie ovens or boiling water may be in order.

    Alternatively search for plastic re-cyclers in your area who may actually pay you for your scrap!



    • #3
      Thanks for the reply Peter, it sounds like just getting a recycling bin might be the idea! But I will see what other replies we get before I work out what to do!


      • #4
        Seems like a smasher would be a lot quieter. Something like two small diameter wide tires (like on the front of a lawn tractor) rolling together. The resulting flats would be easier to handle than shredded plastic.

        Any products mentioned in my posts have been endorsed by their manufacturer.


        • #5
          Check before you do anything

          I would sugget that you check with any potiential recycler before you do anything to your plastics. Some are very fussy on the types of plastics they will accept, on the state of the plastics (original form or shredded) and the quantities. Make sure you have a source and then configure the plasitcs to the form factor they will accept.

          Being ROAD KILL on the Information Super Highway and Electronically Challenged really SUCKS!!

          Every problem can be solved through the proper application of explosives, duct tape, teflon, WD-40, or any combo of the aforementioned items.


          • #6
            I'll second the 2 wheel "smasher"
            I built one years back to do ali cans.

            you will have to leave the caps off or they will blow off, but caps are different plastic so recyclers want them separated anyway.

            Edit to say, the "smasher" was built from an old scooter. Just welded up a frame to hold the former front wheel against the back.
            A bit of sheet metal to funnel the cans between the wheels, kick er in the guts and away you go

            We musta done tons of ali with that thing.
            Last edited by Swarf&Sparks; 07-03-2009, 11:25 AM.
            Just got my head together
            now my body's falling apart


            • #7
              If there is no fuss regarding sorting the different types of plastic, maybe an electric wood chipper could be used.

              They are available with different types of cutter construction, some (like the one in the pic) revolves quite slow and "grinds" the material, while others use high speed cutters (but they're noisy).


              Problems worthy of attack prove their worth by hitting back
              - Piet Hein


              • #8
                Recyclers have chippers or grinders that will make the bottles the size they want. Just take the bottles to them. Or if you have a local pickup option, use that. But even if you make monthly trips, the gas will be far less than a chipper and you still would need to take them there or have them picked up.

                As for using a lawn chipper, it may work just fine, but I would first check with the manufacturer to ensure that is a safe use.
                Paul A.
                SE Texas

                Make it fit.
                You can't win and there is a penalty for trying!


                • #9
                  Shreading would not be so good they would still eat space. find an old bailer at a farm auction and work it over for a stand alone use. if done right it would poop out nice bales of bottles all tied up and everything. un-shreaded bottle would bail up just fine and be real easy to haul.

                  Iv seen old bailer turned into wood splitters too that would split wood as fast as you can fling logs into it.


                  • #10
                    x's 2 for baling.Local pastry works has the same problem with milk and cream jugs.They bought an old cardboard box baler.It makes nice amalgamated blocks about 6" thick and 24" square which will just fit in the garbage trucks plastics door.Think they paid less than $500 for the used baler which also does all their cardboard.
                    I just need one more tool,just one!


                    • #11
                      Check woth your local transfer station or recycling center and see what they use. Ours had a shreadder I used to sharpen the blades for.

                      The next option is to use a compactor, a simple trash compactor for compacting the bottles down quite a bit, available at sears. Your trash man should take the recycling, check with them or the local gubbermint regarding recycling schedules for businesses, or even set up a bit of a consirtium with other local businesses to get a recycling deal set up.

                      I use my compactor for plastics each week just before recycling day, my plastics go from 1 full bag to 1/4 bag and I get my total curbside recycling down to the one bag limit for our community quite easily.
                      CCBW, MAH


                      • #12
                        I've spent the last 30 years working for the local garbage company. Seen the plastics recycling change several times over the years. As mentioned before, the caps are a different kind of plastic, and need to be removed.

                        To be recycleable, the paper label, if any needs to be removed. Given the complications, and the current market around here, I'd advise that you smash the containers and put them in the trash. Any way to reduce the space they occupy will lower your removal costs.

                        I don't know what your volume is, or what your hauling costs are. Geting the air out, and getting them out of your way will probably be your best bet.

                        Before too long the plastics market wiil become more steady, and recycling will become a paying propostion, at least around here.

                        Best of luck,
                        I cut it off twice; it's still too short
                        Oregon, USA


                        • #13
                          Since you probably have a real coffee machine, just put the PET bottles over the steam wand, heat and stomp. The milk jugs will soften too, but you might need to re-cap them once you stomp them flat to keep them from popping back.

                          I don't think shredded jugs would take up any less space unless you had some serious baling ability.