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Shredder for (sometimes) wet garden waste, not to chip wood  RSS feed

 
Dave de Basque
Posts: 126
Location: Basque Country, Spain-43N lat-Köppen Cfb-Zone8b-1035mm/41" rain: 118mm/5" Dec., 48mm/2" July
22
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I tremble at the thought of suggesting such a blatantly non-HUSP-compliant apparatus on permies.com, but so be it.

We have a community garden with about 70 plots of 25m2/250 sq ft. We have mass "barn-raising" days every once in a while in order not to raise barns but to make and turn compost piles, clean and beautify, and remove (heaven forbid) "weeds" from the common areas.

We are looking for a machine to make it quicker and easier to build effective hot compost piles. Our typical pile consists of a bijillion tomato plants all rife with late blight, some with big fat juicy blighted tomatoes still on them, tough discarded pepper plants, bulletproof brassica stems and roots, plus all kinds of weeds, grass and veggie leaves, sometimes diseased with powdery mildew etc. To kill off all the bad guys we need our compost pile to get hot, and we are getting better at building them correctly but honestly we need all the help we can get.

This stuff sits around in a pile in our fairly-rainy outdoors until a community compost-raising day comes around, when it may or may not be pouring rain. So the outside of our piles is often wet and the inside of course is usually dryish -- things can accumulate for months.

Anyway, to reduce the RSI of our team of machete-wielders and speed up the compost-pile-building process, we are looking for a shredder to handle the kind of stuff we will be feeding through it. In addition to the above ingredients, we will usually have a bit of manure of some sort (no shredding needed) and some not-very-shredded hay from a local farm or perhaps dry or wet leaves from the park across the way depending on the time of year. So we want our machine to be able to handle loads of wet leaves in addition to the above if push comes to shove. Even the cheapest shredders would seem to handle dry hay just fine.

Our compost-pile-making area is a long way from the nearest electric outlet -- maybe 200m/yards? In addition, all the reviews of every electric shredder or chipper/shredder I've ever seen warn that this device does NOT handle wet material well.

In fact, the only devices I've ever heard of with decent reviews for shredding wet garden waste have been gasoline-powered (ugh! I feel my principles slithering down a slimy drain) devices with hammermills and free-swinging hammers. (Why you cannot power a hammermill with electricity seemingly is beyond me.) We already have a gasoline-powered weed whacker so I suppose this is just another ways down the slippery slope we'd be traveling.

Anyway, we're now considering devices from MST and Garland that are within our budget but whose technical details we're not so confident about, and a device from Mighty Mac (the SC800) that is 2-3x what we have budgeted but we're pretty confident it can do the job.

I would love to know what some other wise and experienced permies think and have done on the subject.

PS - And if you use a device that shreds wet garden waste well, please let us know the make and model number! Thanks!
 
Roberto pokachinni
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Posts: 1214
Location: Fraser Headwaters, B.C., Zone3, Latitude 53N, Altitude 2750', Boreal/Temperate Rainforest-transition
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Here's my grain of salt, two cents worth:

I don't have the answer that you are looking for, because you seem to be at odds with your gas consumption question... and yet see to be also settling for this as your solution.   So I'm not going to suggest any gas models of which I don't have any to suggest to you anyway at this time.

Also:  I may be wrong but the problem with electrical is likely that the force of surges that are needed to run rough heavy material through blades or hammers is the type of load that would require more amperage than a regular electrical socket would provide, so most models are gas powered, or you would have to plug them in in the place of a welder or a clothes dryer.  The result of running any hard material in an electric model is that it would not handle it, it would jam, it would jolt the machine from high RPM's to zero, it would blow your breaker, and might break the machine.  BUT I'm no electrician and have no experience with electrical shredders. 

That all said, here's my brainstormed PERMIES SOLUTION(?) :  If you have anybody around in the DIY bike community who have a proper shop and some time, and once built you utilize the volume of 'barn raising' bodies to pedal it all at once to generate (via slowly gearing up) the massive RPMs of a heavy fly wheel, I'm pretty sure that you could get a bike powered hammer mill or blade system that would be able to handle anything you chucked in the chute (be sure, of course, to design this so that nobody can get involved in the blades/hammers).  But I'm just a dreamer, envisioning something not an engineer with a working prototype.         
 
Kevin Derheimer
Posts: 65
Location: Fort Myers, fl - Durango CO
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Dave, what you are looking for is an agriculture waste shredder.  I am looking for the same thing,l and did the research not too long ago.  Sorry to say that you may have to import one.  I'll give you a couple of links I found.  I watched a video of one processing coconut fronds and banana plants, you can't get much tougher or wetter than those!  I have dealt with both in south Florida.  There are electric and pto models available.  Some years ago I imported a 700 lb sugarcane press from India.  I saved a ton of $$ doing all the paperwork myself and learned a lot.  I know the carbon footprint represented by the shipping is huge, not sure if it's worse than sepp or Geoff flying around the world teaching pdc's.  Believe me, I have looked far and wide in the US for these things and what I found is either huge industrial models or hugely expensive tiny ones, no "market garden" sized ones.  I have had Indian (dot not feather, for the non-pc challenged ones) friends translate for me when talking to Indian manufacturers.  Most are willing to crate and put their machines on a boat for you.  Anyway, here are some links.

http://m.kovaiclassicindustries.net/agricultural-shredder.html

 


http://www.jaiindiraagro.com

Good luck
Kevin




 
André Troylilas
Posts: 137
Location: North of France
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I've been searching for a "meat-powered" chaff-cutter for a while, and found some still produced in India.
I got some quotes, but the shipping cost is huge.
 
Michael Cox
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Location: Kent, UK - Zone 8
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In my experience, they key to a hot compost pile is plenty of manure wastes.

Our hottest compost piles have always come from when we were using composting toilets and adding them to our typical garden waste mixtures. We have never been keen on turning piles, so our heaps get super hot for a while, then sit for a year to finish off. Pretty much the only things that come through uncomposted after 12 months are really woody branches - usually horrible thorny rose prunings which should never have gone on the heap in the first place.

If your community allotments get a lot of traffic, consider setting up a sawdust toilet for general use.
 
Dave de Basque
Posts: 126
Location: Basque Country, Spain-43N lat-Köppen Cfb-Zone8b-1035mm/41" rain: 118mm/5" Dec., 48mm/2" July
22
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Hmmm... interesting replies!

AND... if anyone reading this actually uses a shredder that handles garden waste, more green tough and fibrous than dry, please chime in with a make and model! Mega bonus points if it costs less than $1000 and is smallish and portable!

The actual model we are considering at the moment is a (link in Spanish but you can probably understand the tech specs down below) Garland 790G which looks a lot like a Mighty Mac model I'm pretty confident would work for us (the SC800) and from what little info I can find in the tech specs, it seems like it may have a hammermill with free-swinging hammers. That's what I've been told (by a Mighty Mac salesman) I need, though I'm pretty sketchy on the free-swinging hammer bit, not being an expert in hammermills. Yet.

Roberto, I love your idea of a mass bike-powered flywheel powering a DIY hammermill! That is not a short-term solution for us but it is a great long-term goal -- maybe we could pull it off around here! We've got lots of bike fanatics, mechanical engineers and welding and boilermaking shops! Thanks for a real permie permie solution! By the way, being in Europe we are on 230V, the equivalent in NA of plugging into the electric dryer outlet, but still, I'm not seeing electric models advertised even here that would work.

Kevin, thanks for the suggestion of an agricultural waste shredder, that gives me another search term to use! These Indian models could no doubt do the job, but are still too big for us. Our entire community garden with 70+ plots fits on well under 1/2 an acre, about 2000m2 if you throw in a lot of the common areas. We have very, very limited storage space, so it needs to be smallish. Also our budget is really around $700-800. We might pay more if there's no way to do the job done otherwise, but that's our limit now... should've made that clear from the outset!

André -- would a chaff cutter necessarily handle wet stuff and tough/stringy stuff like old pepper plants and cabbage stems, etc? Anyway, thanks for the warning on the shipping cost.

Michael... right, very timely warning! We're building our next hot compost pile this coming Saturday the 22nd, and you've reminded me we need to order up a trailerload of cow manure and maybe a dozen bails of hay from the farmer up the road! With maybe 200 people pitching things into our compostables pile, there is no practical way we can keep all the unwanted things out (like rose prunings or what have you), we just need to deal quickly and effectively with whatever's in the pile. (Of course we remove anything stupid like plastic vine trellising, but everything else goes straight in as it's our only waste outlet.) Town hall here supplied the toilets already and they're the plain old flush kind, and I think there might be a bit of political flack at the thought of humanure in our veggie gardens, so I can't see a sawdust toilet on the horizon here any time soon. Ideally, we'd like to get our composting system efficient enough to be on a 4- or 5-month cycle, so October's pile is ready by the beginning of April and November's by the beginning of May. We don't have too much space to keep it around. That's another reason we want to shred, as well as turning a couple of times.

QUESTION OF THE DAY: Any good experiences with a garden waste shredder out there? Which one? (Mostly for annual plants, not leaves, grass, branches or woody stuff)
 
Kevin Derheimer
Posts: 65
Location: Fort Myers, fl - Durango CO
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Dave, I have a troybuild super tomahawk chipper shredder.  It is a hammermill shredder.  It works great for dry stuff, really sucks for wet material.  I have used it for tree/bush trimmings, fallen leaves and to process commercial tree mulch.  Wet stuff tends to wrap around the shaft and sticks in the screen and clogs.  That is why I've been looking for a device to handle wet material.
 
Dave de Basque
Posts: 126
Location: Basque Country, Spain-43N lat-Köppen Cfb-Zone8b-1035mm/41" rain: 118mm/5" Dec., 48mm/2" July
22
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Thanks Kevin!

Wow, this is both great and terrible all at the same time!!! Thanks for the heads-up!

So it is possible for a hammermill shredder also to suck at handling wet stuff. This makes me rethink the purchase of the Garland machine I linked to above as that's really all I know about it. Darn. I mean, good.

Anyway, maybe it is the mysterious "free-swinging hammers" that makes the difference, like the Mighty Mac salesman told me? Do you know if your Troybuild has free-swinging hammers? Maybe this is just a bunch of sales sweet-talk. Any hammermill experts out there?

Or maybe it's a screen size issue? Does your shredder have different screens you can use? If so, which one delivered sucky performance on the wet material?

Or maybe the truth is that EVERYTHING sucks at shredding wet material but just no one wants to come out and speak the bitter truth...

Well, anyway, at least we're a team of two now, looking for something that can shred wet stuff... Hope we find it...
 
Kevin Derheimer
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Location: Fort Myers, fl - Durango CO
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Dave, yes my troybuilt has free swinging blades!  I have removed them many times to sharpen them.  They are carbide, sharpening takes a special grinding wheel, but is easy.  They have 4 cutting edges and swing freely on horizontal shafts with spacers to keep them in position.  There are maybe 20 or so blades.  I have 3 screens, and generally use the medium screen.  Even with the large holes in the large screen, wet material sort of ends up building up over the web between holes,  real pain in the butt to clear.  Even when I process fresh leaves from trimming, I find it helpful to run dry material pretty regularly to keep the screen clear.  It's a great machine, but has limitations,  if you don't clear the output shoot clear, you will have problems, and no matter what the salesmen say, wet stuff doesn't shred well.  I have seen the advertisements on other chipper shredders saying amazing things, but after using mine for 20 plus years, I dont believe any of it.  I grew bananas and coconuts in Florida and made the mistake of trying them in my shredder, once!  That's why I was excited to see the Indian videos of machines taking whole banana trees and coconut frond and spitting the shredding over 10'.  My shredder dumps the shreddings maybe 2' max away from the machine, so you have to continually pitchfork the material away from the chute, so you end up handling the material several times.  Hope this helps, sorry I can't say a hammermill shredder will do more, I would love to be able to dump all of my expired garden plants Into the shredder, but would have to wait till they dried out sufficiently.
 
Su Ba
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I've used a Mighty Mac hammermill shredder for a couple of decades. It works excellent on dry material, and moderately well on moist material. With very moist or wet material, it clogs even with the screen off. For your tomato plants, I would say there's enough coarse vine to keep the shredding chamber clear as long as you use a large screen or no screen. 1" screen would probably clog if there is a lot of tomatoes.

I've run compost-in-progress through it with no screen on. Never clogged even though some pitchforkfuls were rather wet clods. I had a local welder make a bar screen with the bars set 1 1/2" apart. This worked far better than the screens with circular holes.

Now for something that will horrify most gardeners......I use a 6.5 horsepower gas lawnmower with a grass catching bag to do most of my initial shredding of biomaterial. It can handle just about all garden waste except to bottoms of corn stalks. Even the thickest tomato stalks and broccoli stalks get chopped enough for composting. I'm aware that there are some pretty powerful electric lawn mowers out there, even some strong battery powered ones. But I don't know what's available in Europe.
 
Dave de Basque
Posts: 126
Location: Basque Country, Spain-43N lat-Köppen Cfb-Zone8b-1035mm/41" rain: 118mm/5" Dec., 48mm/2" July
22
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So OK, now I'll fess up. Our stuff isn't likely to be *all* that wet. If it's pouring rain on compost-raising day we'll put it off till the next week. And it's not *really, that* rainy around here.

So here's my evil plan -- do you think it might work?

Let's say this Garland machine I've got my eye on is not as good as Su's Mighty Mac, it's about like Kevin's Troybuilt. Hope springs eternal, I hope we don't buy a €700 lemon.

About half our compost fixins are *dried out* plants, including brassica stocks, pepper plants, whole tomato plants with tomatoes, "weeds" and loads of other stuff. Another 40% is the same but fresh and green. The last 10% is the outer layer, which is the same but pretty wet from a few days of rain that just let up yesterday.

Enter, stage left, for compost-raising day, about half the volume of our compost fixins in bales of dry hay.

And let's say we leave the screen off this non-lemony Troybuilt-like shredder for the first pass.

We alternate the wet outside stuff with dry hay and then throw in some dry and green middle-fixins. And we get through the pile with almost no clogs.

Then, since we want this pile to compost fast, we put a 1" screen on and feed it all through again. The wet stuff won't be as wet since it's mixed with a good amount of dry stuff now. So it won't stick, will go through and get minced up just fine and we will all live happily ever after.

Ooops I forgot, then we layer the product of round 2 with fresh cow manure (like 10% of the volume of the original pile), water well, throw some hay on top to keep the rain off, and we're cooking.

Do you people who've actually used these things think that this is outrageously idealistic? Or maybe might work out like this?

PS - What's the safe way to unclog one of these contraptions? Don't want anyone losing a hand.
 
Kevin Derheimer
Posts: 65
Location: Fort Myers, fl - Durango CO
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Dave, leaving the screen off on the first pass may work pretty good!  Especially with weeds, that may not shred very well anyway.   With my Troy built, leaving the screen off will knock stuff apart but not really grind it up, it needs the screen to keep the material in the shredding chamber to work on it.  For your purpose, just knocking the material apart might do well for you to reduce loft, then process again later when it has decomposed.  I have a huge pile of horse manure with lots of hay and big hunks of poop mixed in, it's dry and I use it to layer on another compost pile.  I'm planning to run the horse poop pile thru my shredder to make finer brown material for quicker composting.  I have also run garden soil thru the shredder to mix and make beautiful fine soil for seed beds, be careful of rocks, they dull the blades quickly and if you are like me, I removed the flexible shield so I could easily shovel or pitch fork stuff into the top, they can shoot back out the top, as well as make an awesome noise (my shredder has some nice rock dents in the steel walls). It's not too hard to unclog, I just disengage the drive, remove the screen and scrape off with a sharp, wide putty knife.  Just keep in mind that the blades swing very close to the screen, so keep fingers well away, I will admit that I sometimes use a stick to rub against the screen to free stuck material, it gets chewed up pretty quickly!  Also, my shredder will rip material out of my hands with surprising speed, reminds me to treat it with a good deal of respect.  I would learn to sharpen the blades, it is not hard and taking the blades out will give you a chance to look over the guts so you can see if any problems develop.  Let us know how it goes.
 
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