[USCC] Low cost compost screener

Frank Teuton frank.teuton at sympatico.ca
Thu Dec 21 10:35:08 EST 2000

OK, Carl,

Sounds good, then.  I was wondering how you dumped the rejects, and it
sounds like you have that well figured out. The portability and sturdiness
of your device looks like a winner for the tractor owning masses out there.

Have you considered trying to convert a stand alone concrete mixer, for the
tractorless market gardeners and family gardeners out there? Any thoughts on
that? And what about the manufacturers, perhaps you could interest them in
tweaking out this idea?

For removing plastic bits from the screens, I use a harper's brush, and
perhaps you could put one on a broom handle and get good screen clearing
with it? You can work the brush from both the inside and the outside of the
screen, eh? (Or just use a suitable broom, too)

Twenty minutes is not so bad in the screen changing biz, I would have
thought it took longer....

You know, much of the screening technology that would be suitable for heavy
duty use has been developed in the mining industry. Sometime we should hunt
down some mining engineers with knowledge about this and get them to divulge
it. They might be able to save us a lot of grief, eh?

Meanwhile I pre-screen stuff that is too rocky and stumpy before applying it
to smaller screens, and would guess that would be the way to get out most of
the bricks, rocks, bottles, engine parts etc that people commingle in their
organic wastes. I'm a landscaper so a lot of the stuff I compost is what I
gathered myself, but I do snag bags from curbsides now and then, and
occasionally get a nasty surprise or two. You can also pick out most of the
evillest things in the shovelling/forking process. I use an heirloom potato
hook for that, which snags most of the big chunky items before I fork or

It seems to me that what Leon's Big Sifter has on yours is not so much speed
of operation as it is the ability to feed it with a front end loader. Any
satellite type for a PTO tractor would need to be big enough for this, also.
Of course, then you'd need two tractors, eh? But many people out there could
borrow a second tractor for a few hours, couldn't they?

Not that I oppose shoveling multiple yards of compost into a sifter, you
understand. I have been doing it for years, it is fine exercise, and all
that, but it does seem like more folks might be more interested if we could
mechanize that part of it also...

Thanks for the input on the satellite screener, I was unaware it relied on
high speed to accomplish its work---still, couldn't some happy balance
between tilt and speed be achieved, along with smooth metalwork, to make it
more foodweb life friendly? I am thinking particularly of worm harvesting
although other critters may be a bit fragile as well. Even with worm
trommels mortality can be as high as 30% post-harvest.

One other note here, there is another small sifter out there now being
commercialized, which is smaller than yours, but still may be the tool for
the job for some of the tractor-less farmer/gardeners on the lists receiving
this. It is the Mister Sifter, www.mistersifter.com, which is basically a
little A-frame with a vibrator on it, a scaled down version of Leon's thang.

Perhaps between this and Leon's behemoth, you could find a happy medium that
would combine sturdiness, portability, reasonable cost and the ability to be
fed with a front loading tractor bucket. And, they even make buckets now
that will do some sifting for you, see for example the Allu SM, illustrated
on page 13 of the August 2000 issue of Biocycle www.biocycle.net.

It would be very interesting to see all this stuff evaluated and compared
side by side. I would frankly find it a more worthwhile sort of Olympics to
have an agro-horticultural friendly competition where all aspects of these
technologies, including costs, labor, speed, etc, were openly and fairly

Anyway, good to hear from you Carl, and if soil people someday make the kind
of money baseball players do now, it'll be a better world!

Don't be siftless,

Frank Teuton

----- Original Message -----
From: "carl weston" <provfarm at netunlimited.net>
To: "Frank Teuton" <frank.teuton at sympatico.ca>;
<compost at compostingcouncil.org>
Cc: "Sustainable Agriculture Network Discussion Group"
<gevanylo at vt.edu>; <market-farming at franklin.oit.unc.edu>;
<compost at lyris.cahe.wsu.edu>
Sent: Thursday, December 21, 2000 12:15 AM
Subject: Re: [USCC] Low cost compost screener

> Frank,
>      Thanks for your feedback.  Where were you 2 years ago when I was
> looking high and low for screening alternatives.
>      You mentioned the Satellite Screen company.  I am familiar with some
> their products.  I spoke with the developer of that type system, and he
> me that at one time he had made some small units but could not make them
> work financially.  I even tried to talk him into making me a "dish" that
> would be a suitable size for mounting on a tractor, with no success.  The
> philosophy behind these dish type screening systems was what got me
> interested in trying to build my own screener.
>      The original grant I applied for had two parts.  One that utilized
> stock mixing container modified as you see on my web site. For the second
> part, I had planned to develop a hybrid between the stock cylinder and
> of a dish, like the satellite screen and mount it on the concrete mixer
> frame.  Unfortunately I am new to grant writing and underestimated the
> and money just to put together the first phase, so the hybrid container
> have to wait for the time being.  The underlying mechanics of using the
> concrete mixer are still good, but I would agree the stock drum is not
> ideal.  The key, as I understand it, to the dish type screeners is precise

> angles and speeds will tend to kick oversized heavy particle out of the
> dish.  (I disagree with your point that the dish type screeners would not
> destructive to worms.  I have a video of these screeners in action and
> are by no means gentle to the contents.)
>     The problem I encounter with some yard waste, is trash which does not
> "kick out" of the drum since it is often lighter.  This trash would also
> likely be a problem going through the worm type screeners and could
> be more difficult to clean out because of the length of the cylinders
> it has to be removed from the inside.  The worm screeners look very good
> what they are designed to do.  If they had a beefed up version, I am sure
> they would be able to handle the tougher grade of materials I sometimes
> to deal with but the design is nice.  I had heard of grain cleaners
> in design, but the folks I talked to thought they also were not heavy
> to deal with the occasional rocks.
>      Another aspect that I was attempting to address was developing a
> solution for those folks out there that are not that "handy" when it comes
> to tools.  The modifications to my stock machine took under 10 hours and
> done with very basic tools, and minimal skill.  While low cost is
> I think my screener solution is a good value despite its short comings.
>      You mentioned changing the screens looked problematic.  20 minutes to
> change out the screen is not excessive to me, and I think my fastening
> system is most likely stronger than the worm screeners.  I can sometimes
> some heavy debris such as bits of bricks, rocks, concrete, etc. that tends
> to get mixed into the piles at the municipal yards.  The rugged fastening
> system seems warranted in my case.
>      To get ride of  the oversized materials and trash is not that big a
> deal, though not as nice as the worm screeners.  The beauty of using the
> concrete mixer mechanics is that it has a hydraulic cylinder on top link.
> All you have to do is dump the screening container with the tractor
> hydraulics while it is spinning, and the oversized materials roll right
> into a trash can positioned at the opening.  This clears out 90 percent of
> the trash very quickly.  On the web site you can see the pile I was
> on had a great deal of little pieces of plastic that got wrapped around
> screen mesh.  This dumping technique was unable to get ride of this type
> debris.
>      One other benefit of using a PTO driven machine is the ability to
> the screening cylinder at nearly any speed you want.  This allows
> revolutions per minute to be adjusted depending on the screen size and the
> material being screened.  Having it mounted on the tractor also makes it
> easy to bring the screener to the pile.
>      Thanks for putting together all those links.  It's good to know that
> stuff is out there.  Let me know if you want to foot the bill to build a
> dish attachment.  Sorry, its not in my budget this year.
> Good luck,
> Carl Weston
> ----- Original Message -----
> From: "Frank Teuton" <frank.teuton at sympatico.ca>
> To: <compost at compostingcouncil.org>
> Cc: <provfarm at netunlimited.net>; "Sustainable Agriculture Network
> <gevanylo at vt.edu>; <market-farming at franklin.oit.unc.edu>;
> <compost at lyris.cahe.wsu.edu>
> Sent: Wednesday, December 20, 2000 6:01 PM
> Subject: Re: [USCC] Low cost compost screener
> > Hi Greg and Carl,
> >
> > Interesting concept, guys. However, methinks you are reinventing the
> wheel.
> >
> > Small screeners with this kind of throughput already exist and can be
> > purchased, for example, from vermiculturists, such as Kazarie Worm Farm,
> > Rainbow Worm Farm. and Vermico.
> >
> > www.kazarie.com
> >
> > www.rainbowwormfarm.com
> >
> > www.vermico.com
> >
> > DIY buffs with a one site operation can also turn to Leon's Big Sifter
> > ideas, see the Master Composter site run by Mary Tynes,
> > www.mastercomposter.com
> >
> > http://www.mastercomposter.com/leon/leonsift.html
> >
> > Small scale operators who don't want to invest yet in a $1,000+ sifting
> > apparatus can always turn to various smaller size sifters, from the
> > venerable A-frame to my own little creation, the Cantopper. These tools
> can
> > enable someone with more labor than capital to get started, then shift
> > bigger and motorized machinery as it becomes justified.
> >
> > See http://www.mastercomposter.com/equip/sifters.html
> >
> > Looking at the website, I have the following observations about this
> > contraption. Compared to a worm trommel, this thing seems to have no
> output
> > port, so that you load, sift, and then offload the rejects periodically.
> > That seems awkward to me. A smaller, slower revolving system that could
> flow
> > steadily would seem to me more efficient, and perhaps also more gentle
> > the compost foodweb organisms---it looks to me like the speed of this
> thing
> > would do some harm to a fair number of valuable foodweb community
> > from the video clip.
> >
> > Secondly, the worm trommels allow a fast change of screen sizes; this
> device
> > seems unwieldy in this regard, also.
> >
> > I do have another idea to offer.  Satellite Screens, Inc, made a run of
> > small garden size versions of their satellite screen concept, which is
> > offered in the large version by Fecon
> > This concept can accept moist materials, and run at a reasonable speed,
> > would be friendly even to worms, and it would seem to me, could easily
> > adapted to a PTO system, at the right scale, and would be in the same
> price
> > range as the one you made with greater capacity and flow.
> >
> > That would be an interesting investigation for an appropriate screening
> > technology, for the small market farmer/gardener. To be worthwhile, it
> would
> > have to be significantly faster or easier to work with, or less
> > than, or more sturdy than, existing commercial small scale screening
> > technologies, mentioned above.
> >
> > Good composting,
> >
> > Frank Teuton
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Greg Evanylo" <gevanylo at vt.edu>
> > To: <compost at compostingcouncil.org>
> > Cc: <provfarm at netunlimited.net>
> > Sent: Wednesday, December 20, 2000 3:08 PM
> > Subject: [USCC] Low cost compost screener
> >
> >
> > > Please find below the address of a website that demonstrates how to
> build
> > a
> > > low cost, small volume compost screener. The website was developed by
> Carl
> > > Weston (provfarm at netunlimited.net) for producing a high quality
> > > potting medium. Carl developed the screener using funds from the USDA
> > > Sustainable Agriculture Producer Grant Program. The website provides
> step
> > > by step building instructions, a budget, and contains footage of the
> > > screener in action. Feel free to share the website address with those
> who
> > > may have an interest in constructing such a screener. Carl would
> > appreciate
> > > suggestions on how to publicize his website.
> > >
> > > http://www.carolinafarmstewards.org/compostmixer/
> > >
> > > Gregory K. Evanylo
> > > Crop and Soil Environmental Sciences
> > > 421 Smyth Hall,  Virginia Tech
> > > Blacksburg, VA 24061
> > > Ph: 540/231-9739;  Fax: 540/231-3075
> > > gevanylo at vt.edu
> > >
> > >
> > > _______________________________________________
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> >

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