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Tip - shredding various materials for bulking

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  • Tip - shredding various materials for bulking

    I happen to have the Bosch Shredder AXT 25 TC which is a nice chipper (eats moderate sized branches and is quiet). Apart from the obvious use of generating woody chippings for hot composting, I've found it seems to be happy to eat corrugated cardboard.

    Disclaimer - make your own judgement as to whether to think this is a good or bad idea for your machine... They're not explicitly sold for munching cardboard and it is a different material to greenwood, so keep an eye on your cutters.

    My technique: remove any plastic tape etc.

    Slice or tear cardboard into lengths no wider than about 6-8" with the corrugations running longways. This allows you to roll the cardboard into a stick. Feed it into the cutter same as a branch.

    Result - 3" or so by 1" shreds - a very nice size for adding to grass.

    For other material, a regular paper shredder is a good way to turn junk mail and (more importantly) old bank statements into carbon rich material. I add a handful to the bottom of the kitchen food waste bin which keeps it cleaner and reduces smells. This then gets added to the HotBin with the food waste.

  • #2
    I have one of those Bosch shredders and tried pushing cardboard throught it but the result was not good - bits of cardboard were too large and only partly shredded. Mind you it has had a fair bit of abuse over the years so the blades may not be that sharp. I will certainly try your idea of rolling it into rolls tht look a bt more like branches - sounds like it may have a better result.

    While I'm talking about shredded cardboard (SC), I finally found a great solution, but only after much hunting....
    There is a small market for shredded cardboard as horse bedding. There are a few (not many) firms making this stuff. It's great - if you want 20 x 20kg bales delivered! (Pearce EcoBed, Ecobale and there's a couple of firms in Dorset, I think). The trouble was finding it somewhere local where I could buy one bale. Finally found a local farm/equine supplies place who stocked it and bought one 20kg bale for £7 or £8 if I recall correctly. It's great stuff, mostly chopped to approx 2-3cm square so perfectly sized for use in hotbin.

    20kg lasted me many months. Went to get some more, but they are out of stock and have been for a while and no idea when it will come in. They stock Pearce EcoBed. Pearce's website has a news item from late 2017 re changing the 'formula' to allow some plastic tape - a problem with getting supplies of untaped material, I suspect. I called them to ask when they would be supplying retailers again. Answer: we have no idea - we cannot source enough material through the supply chain to produce the volumes we need.

    I am staggered that there is any difficulty in sourcing recycled corrugated cardboard.

    On the one hand I suspect horse people are not yet converted to this stuff and prefer their traditional bedding materials so the market is perhaps not huge enough to justify further investment by larger producers, but on the other hand, there is clearly demand and the industry (such as it is) cannot keep up. I phoned another source, and jokingly said they should call the Pearce retailers 'cos they could clean up while those are all out of stock! The response implied they can hardly keep up with the demand they have with existing customers.

    Other sources seem to be small-scale/local enterprises with limited reach and capacity. Great if you live locally and can collect (assuming they have stock - two had answerphone messages, suggesting very small operations, and the last such one I talked to also could not keep up and seems now to have gone out of business).

    So, I reckon there's a market opportunity out there (hello Hotbin, hope someone is reading this).

    Other sources (eBay, pet supplies, etc) offer too small quantities at 2-4 (or more) times the price. I even looked at the cost of a shredder capable of handling corrugated cardboard but that is silly money (for domestic use).

    So ... until I find another local source of shredded cardboard horse bedding, I'll give the Bosch another go with your suggestion of making cardboard 'sticks' for shredding.
    Last edited by george57l; 06-19-2018, 04:27 PM.


    • #3
      Hi George571,

      Thanks for your post.

      Can we ask whether you are using the cardboard as a medium to rebalance the moisture content or as a form of bulking agent to help create air pockets throughout your HOTBIN?

      We look forward to hearing from you.


      • #4
        (2nd response to your replies today - read other first please - this continues the discussion)
        It is possible that I was not using enough bulking agent and did use more cardboard than otherwise, to compensate, on some of my earlier batches where the bag was still in place. But I am primarily using the cardboard as brown material to balance the green material (i.e. balances moisture content too). So your suspicion that I was not using enough bulking agent, resulting in anaerobic mess may possibly be correct, though in the past I *still* had a sodden bag (see other discussion) even when the temperatures barely got to or exceeded 40degrees (possibly due to insufficient bulking/air pockets) and in which case presumably far less moisture/vapour was being sent up to the bag/vent.

        But why do you ask? Is corrugated cardboard - with its plentiful air pockets, not able to achieve the same effect as bulking agent? Hmm - I guess not, once it has got wet and collapsed, perhaps? But surely it performs that role at least in part while its corrugations survive? I seem to recall one of the reasons Hotbin gives for using corrugated (as opposed to flat board like ceral boxes/egg cartons, etc) was precisely *because* it has air pockets - serving a dual purpose: providing air, as well as brown material to balance the green.



        • #5
          Hi George571,

          We're more than happy to talk to you about this over the phone (as per our other thread on the forum) but for the benefit of other HOTBIN forum members, unfortunately cardboard, whether flat or corrugated does not offer enough rigidity or structure to help aerate the contents of the unit. This is because the continuous process of adding new waste into the unit every couple of days quite quickly compacts the cardboard, eliminating any small air pockets that the corrugated flutes may have temporarily created.

          Shredded paper and/or cardboard is added into the HOTBIN with the sole purpose of helping to absorb excess moisture from the unit, preventing the contents of the HOTBIN from becoming too wet.

          For a bulking agent, we advise using a medium such as wood chips or chopped/shredded hard woody prunings from the garden as these offer a more rigid structure in the short term which allows air pockets to be created within the unit and allow the oxygenated air to circulate throughout the HOTBIN and keeps the hot composting bacteria operating aerobically but which will still decompose to become part of your end compost in the medium to longer terms.

          Regrettably neither material can be interchanged as they perform different roles in the unit and structurally different.


          • #6
            Yeah - I do get that - especially after some personal experience - one load at least where I probably added insufficient bulking agent. Although I do dig down and try to aerate lower layers and bring some up to mix with latest addition, every time I add a load. But, again, I'm sure I did read somewhere in your material that corrugated was preferable to flat precisely because of the air pockets it provided. If that message persists in your written material anywhere, it may be wise to add a comment that nonetheless corrugated is no substitute - even in part - for bulking agent.