Here is a video showing a pretty good compost tumbler. Using thought, I came up with the additional design criteria. Obviously cost and time are necessary to keep under control so that this black gold generator "makes sense".
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This one looked pretty good. Looks like he had a
lot of time on his hands….
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Compost tumbler design requirements
11
Ventilation, oxygen a very important part of
this process. The holes should be on
the ends of the drum, not on the barrel itself. On the barrel will cause 2 problems, the
water you add to enhance the composting will leak out, and the compost may leak
out too.
22
Ventilation holes should big bigger rather than
smaller and located to the center of the end (closer to the rotation pipe, but
not so close that the structural ability of the end plate is degraded). Picture 200lbs of stuff in the barrel,
max, usually probably 100 lbs load.
33
Ventilation holes should be fly protected. There will be raw food in these tumblers,
flies will be annoying at best, and disease spreading at worst.
44
Consider a barrel mounted “drain plug” of some
type in case there is too much water inside and you want to drain it. A 3/8" lag bolt may work well enough, 1 or 2 of them should be enough.
55
Having a few “mixing plates” inside the tumbler
may help mix things, although the rotation should probably be good enough. Don’t get carried away with too much time or
money for mixing plates.
66
The handle is a great thing, especially with a
plastic pipe over the steel pipe…will be warm to the touch in cold
weather. Consider that women and
children will be rotating the tumbler, make is user friendly so they want to
use it.
77
It is better to have the center pipe attached to
the barrel, and rotate on the wood.
Otherwise, eventually the barrel wall will be degraded and be a tough to
fix problem. When the rotation part
hits an easily replaceable 2x4, no problem.
88
Access door should be pretty big, bigger than
what the videos show. At some point you
will want to remove 100 lbs of compost, dumping it into a wheelbarrow most likely. You don’t want this to take forever, you
want to be able to stick arms and push shovels inside.
99
Should be high enough that you can get a wheel
barrow underneath it, but not so high that 5’ tall person cant load the hatch
easily. Loading may be every day or
every other day, so that part should be easy too. A simple to use latch that will stand up to
weather is essential
110
The hatch doesn’t have to fit super tight to the
barrel…the barrel can always be stopped in the hatch up position.
111
Barrel should be black, in a 4 season operation,
you want composting to work as well as possible right through winter. Black will help absorb heat and promote the
process.
112
Consider some day maybe wanting to have a very
slow rotating motor turn things, a handle on one side is all that is needed,
leave the other side as a pipe extension so that a gear set could be welded to
the pipe.
113 Possibly down the road, worms may be added to accelerate the process, although tumbling action would have to kept to a minimum. Red worms seem to be the accepted norm.
Arrrg! It just doesn’t store right! (Yes, even I get OCD sometimes…)
