Composter (Drum Style)

This composter rotates so that compost matter can breathe (which should also minimize odor) and break down a little faster. I created this prototype in about 2-3 hours. This project applies the fine art of meatball carpentry--emphasis on function NOT aesthetics. The materials should run about $10-$15. I don't know what the weight limit is for the compost matter.

UPDATE: There was some concern that the compost mass would be excessive (someone estimated 300 pounds). Currently, the cylinder is full with composting leaves and kitchen discards and it weighs roughly 35-50 pounds.

Step 1: Materials/Tools List

MATERIALS
2-Plywood 2' X 2' (This will be cut into a circle Radius= ???)
Fence wire 3' X 62 (Try to use a fine mesh--mine is ~1/4")
1--2 X 4 X 92-5/8"
1--1 X 4 X 48"
PVC 3/4" X ~35"
~49" Rebar
Nails, staples, glue

TOOLS
Measuring tape
Circular Saw
Sabre Saw
Drill
Hammer

NOTE: I will update this soon with more specific info

Step 2: Stage Materials

Note: Your setup may deviate from mine. If so, recalc the dimensions. For the most part this project uses very basic pieces so, for example, if you use a circle that is larger you can re-measure the vertical supports and go from there.

--Cut the plywood into a circle with 10 1/2" radius. (Try not to notice that my circle cut was a little lopsided :)
--Cut 2--2 X 4 to 26"
--Cut 2--1 X 4 to 24"
--Cut PVC to 35"

The wire mesh I used was 3 feet wide and ~62" long.
The crossbeam that goes over the hub should be cut to size based on the size of your drum.
If you are going to use a pan to catch compost that falls thru the wire mesh then increase the height of the 2 X 4. Then adjust the hole in the 2 X 4 so that the drum is higher off the ground, allowing more clearance.
NOTE: I will add more details (e.g. dimensions) soon.

Step 3: Build Stand

Nail and glue 2 X 4 (vertical support) to 1 X 4 (footing).
(refer to photo)

Step 4: Create Drum Section

Run rebar thru round cut plywood, PVC and thru stand (refer to photo).

Staple wire to round cut plywood.

Measure the size for the cross beam and nail/glue it to the vertical supports.

Step 5: Finishing Touches

You will need an opening to facilitate adding organic material (and later removing finished compost). The wire mesh is sharp at the opening so wrap it with duct tape or make some other accommodation to avoid cutting your hands. Also, you may want to fashion a door for this purpose. With a door, you should be able to completely rotate the drum.

NOTE: I am working thru how to do this step. PLEASE chime in if you have ideas.

Step 6: Using the Composter

The composter should be positioned where it can drop small compost matter on the ground or in a pan. The compost should heat up during the composting period and cool down as it completes the process. The main idea is to shorten the amount of time for creating compost so take any steps that will hasten this end.

Here is a list of basic compostable material:
--coffee grounds
--tea bags
--vegetable and fruit peels and clippings
--egg shells
--grass clippings
--leaves

DO NOT ADD...meat, dairy products, metal, slow composting matter

Make sure to rotate the compost using the attached arm. Also, make sure to keep the compost moist.

Comments

[Sterrej13]

Hi there, I am currently making this composter. I just wonder how big did you made the holes for the rebar? I am guessing the holes in the wooden stands are slightly bigger as you don't want those to turn with the composter. My rebar is 9.3 mm and was thinking of making the hole 8.5 mm but I am really not sure.
Thanks! Sterre

[jamesglasner]

To make a door on the drum to stop leaves and other materials from leaking, cut a 1” notch on both circles wide enough to fit a board inside the notches and below the board covering the ends of the wire mesh. The board can be run between the circle ends to trap the materials and easily removed to add more materials.

[Stuttz]

how do you stop it from leaking when you add a little water

[javajunkie1976]

I've made similar compost tumblers yet when I go away, they still need to be turned.

So, what I did was to attach a slow RPM motor like a rotisserie motor controlled by a water sprinkler timer which also controlled a drip line that was placed over the tumbler. First the timer starts the motor, then after 5 seconds, the drip line is activated. After about 10 - 15 rotations, the drip line is cut off. The tumbler is continued for another 1/2 hour to make sure everything is mixed. Inside the tumbler I use 1x3 strips to act as "blades" (kind of like what's in your dryer.)

I usually set the timer for 1 activation per 3 days. I've gotten very good results this way.

[HenrikOlsen]

Quite late to comment I see, but I'd make the mesh as a spiral as in the attached doodle.

Turn the drum one way and the compost is mixed and aerated, turn the other and the drum is emptied.

[ERCBIENG]

 Clever!

[karo1039]

I don't think it has been brought up, but another modification you could do is to add something on the middle rod to make sure the pile gets mixed up, so the middle of the compost pile doesn't stay in the middle.

[hv3333]

There are simple tricks to mark out perfect circles, like using a nail, some string & a pencil to make a giant compass. An alternative might be to track down one of the plywood drums electrical cable (the larger scale stuff, not standard house wiring stuff) comes on - ready made circles with central holes. I was also wondering about putting the central axis slightly off-centre - if it was moved up very slightly (I'm thinking an inch at most) the drum would naturally settle in the same position the whole time. Another method might be to add a weight to the bottom. Just make sure you position the opening in the right place!

[ruthy nov]

To make a door you can simply leave your wire mesh longer about 2-3, staple as described, (leaving an opening), attach velcro to the flying end and to the secure end so you can close and open easily.
To keep your fingers from getting hurt by the wire, take a long enough plastic tube, cut a long cut and insert the wire mesh in it. It will hold nicely.
Thank you for all your wonderful projects!
old lady.

[soad17111]

this looks like a good idea. I am starting to get into saving the inverment. So i might use this.( or something close)

[TimBTodd]

environment*

[WalkaboutTigger]

I am going to recommend a slight modification. I live on the coast in California and in order to maintain appropriate temperatures within the pile, I wrap my bin with a blue or black poly tarp and secure it tightly to the drum with black rubber bungees. I added a gromet in the middle of the tarp to insert a thermometer but you need not do this if your needs to not extend to using a thermometer. The other advantage of the tarp is the prevention of leakage of fine particles (such as coffee grounds) during rotation. The tarp can also be completely removed and cleaned if necessary. Do not use a cloth tarp as they tend to compost very readily. Pre-cut round sections of plywood can be purchased from most home improvement stores. I also added 6-inch semi-pneumatic tires to my compost drum so I could move it around with my lawn tractor to the various areas of my property.

[jdlink]

WalkaboutTigger...good suggestion. Composts have different needs depending on your environs. For example, if it rains a lot, you may need to have a provision for limiting the moisture. If it is a dry climate, you may need to water the compost on a regular basis. As WT points out, you may need to provide for cold or hot conditions as well. My compost setup allows fine particles to fall thru. It would be a good idea to put a pan below composter to catch the particles...they are now ready for use.

[babybackribs]

suggestion- Wouldn't using clear plastic be more viable? Kind of like the greenhouse effect where the sunlight goes in but cannot escape, that should keep it good and warm no?

[WalkaboutTigger]

The challenges with using clear material are that clear material becomes opaque over time due to scratches and embedded debris, ages much more rapidly in the elements so it cracks and fractures, clear material that is IR transparent in one direction only is expensive, some of the microbes in compost piles experience significantly reduced reproduction in visible-spectrum light. Another 'attraction' to the black polyvinyl tarp material is that it can hide the less attractive aspects of the composting process so you don't have hide the compost drum, in limited space yards, when having friends or guests over - yes, vanity has its place!

[djsc]

I like this idea, could do it to any compost heap too.

[galadriel]

For a door, since it it wire, take a look at the doors on wire rabbit cages. The door itself is wire, it's held on with wire loops, and another bit of wire forms a locking latch. You could easily cut a door area out of your wire and make a wire dor to go over that cut out area.

[cindynsg]

I think I would use a plastic drum with the round plywood as support with a solid bar (like for weights) & PVC. The stand will work, provided the base is wide enough. At any rate, cut a flap out of the side of the drum, apply a piano hinge with support for for weight and a two slide bolts with supports behind them for added weight. If you want a screen, then you can make one to slide in when you open the flap door. Making a completely screened unit doesn't let the material compost because it lets too much air in. The idea is to get the material hot, sot the darker the barrel the better.

[pinoymale]

I just recently started learning about composting and this looks like an ideal project for my small apartment. Forgive my ignorance, but are you supposed to add soil to the above list of compostable material? How long will it take before it starts creating compost?

[jdlink]

pinoymale, I am not sure a compost system is a good idea in an apartment since it will attract various types of bugs. In some cases, you can store compostables in doors overnight (covered up) but any longer is risky. I don't add soil to my compost. I just harvested some compost that I started last year. It was really rich but as usual it is not completely digested. The compost drum may speed up the process but you may have to be very proactive...water compost when dry and turn it often. My guess is allow at least 4-6 months for the compost to break down but 1 year might be more realistic for black gold.