Create an effective and sturdy compost tumbler in 1 - 2 hours, with little out of pocket cost. These tumblers were built using materials I had lying around the house, and from items obtained through Freecycle. The only out of pocket expense was for the conduit/pipe brackets (less than $5 for the three tumblers I've made so far). Composting with these tumblers has proven to be extremely easy, and quite a bit quicker than our old "pile" method.
Step 1: Get a Barrel
A barrel with a large, securable top is the key. We found 4 of these 50 gallon barrels through a post on Freecycle. They originally contained grains, and came from a brewery. These barrels are light enough to transport easily, but sturdy enough to take a beating. The large opening makes it easier to put organic material in the barrel, and the screw top lid easily contains everything as the composter is tumbled. A word to the wise: leaving the barrel upside down in the winter is not advised. We found one of the lids frozen shut when left in this position!
Step 2: Gather Materials and Tools
- the barrel
- 2 x 4 lumber: approximately 24' per barrel stand. I used scraps from a construction project
- 3/4" galvanized conduit or similar, non corroding pipe. Approximately 3' per composter
- 2 heavy duty conduit/pipe brackets to attach the conduit to the stand.
- galvanized/decking screws
- drill (an electric/corded drill works best for this job)
- 3/8" and 1" drill bits (spade bits like Speedbore are best for this job)
- saw (if you've got access to a miter saw you'll be much happier)
- phillips screwdriver
Step 3: Cut Lumber and Assemble the Stand
Build 2 triangular side stands for each compost tumbler. Dimensions may vary, based on the size of your barrel. The object is to create a stable platform for the barrel, while also allowing enough space for the barrel to spin freely. All pieces were cut from framing grade 2 x 4 pieces I had lying around, which then needed to be painted for protection from the elements (we were unwilling to use pressure treated wood for this project)
Measurements for this type of barrel:
- base/feet 56" (x2)
- uprights 32" (x2)
- angled supports 40" (x4)
- cross brace 32" (x1)
The cross brace is critical if you do not have a way to attach the stands to a cement pad or otherwise affix the assembly to the ground. I found it easiest to cut and assemble all the pieces at the same time, then paint them all at once. While the stands dried, I went on to the next step.
Step 4: Drill Holes in the Barrel
Air circulation is very important for proper composting. I used a 3/8 spade bit to make a large number of holes in the barrel. Although it's not crucial, I tried to space these holes out in staggered levels to ensure maximum cross ventilation. Experience has taught me to also drill a number of holes on or very near the bottom (and top), to allow for drainage. This step will not be necessary if your tumbler will be protected from rain. Without the drainage holes, I made a messy (and smelly) soup.
Experience has also taught me that 3/8" holes are a good size. Larger holes may allow for more air flow, but they also allow material to fall out and make a nice pile under the barrel. Larger holes allowed the local wildlife to sample the melon rinds and other tasty bits we put in the composter.
Spade bits are extremely efficient at this task, and the higher speed of a corded drill was helpful.
Step 5: Fit the Conduit/pipe
Here's where you'll need the 1" spade bit. Although the conduit is 3/4", this is an interior measurement. The hole in the barrel needs to be large enough to let the conduit to fit easily. This will allow the barrel to spin freely once everything is in place.
Make a 1" hole at the mid point of the barrel. Using line of sight, make a hole at midpoint on the opposite side of the barrel. Extreme precision is not critical here, but come reasonably close. It's more important to have the holes at the same height than perfectly opposite, otherwise the barrel will lean and slide over time.
Cut the galvanized conduit to length. The conduit should be at least 1' longer than the width of the barrel. In this case, the conduit was cut to 32". Slide the conduit through the barrel and make sure the barrel can balance while suspended by the conduit.
Step 6: Attach the Conduit to the Stands
Connect the 2 triangular bases with a cross piece (in this case, 32" long) using 3" galvanized or decking screws. Place this assembly on level ground.
You'll want another person to help you with the next part. First, mark the uprights to indicate where the conduit brackets will attach (in this case, 29" above the ground). Have your helper hold the barrel aloft and align the conduit and brackets with the mark on the upright. Using a short (1") galvanized or stainless tell screw, begin affixing the conduit brackets and conduit, but do not tighten at this point.
Slide and adjust the conduit until it is equidistant between the uprights (make sure there is at least 2" of space between the uprights and both sides of the barrel). Once properly aligned, finish tightening the screws and completely secure the conduit.
Add a mix of green (fresh) and brown (dried leaves, etc.) organic materials to the barrel, filling no more than half way at first. Give the tumbler a spin every few days, and begin adding more material as time goes on. We've found it necessary to have more than one tumbler, and staggered their "start" dates so we have a steady supply of fresh compost. To extract compost, simply place a tarp under the barrel, open the lid, and dump! We tried making these composters taller, so we could put our wheelbarrow under them and save this last step. Unfortunately, the lid was so high it was difficult to add more material to the barrel.
Please comment! This is an assignment in Pedagogy II at Marlboro College Graduate Center's Teaching with Technology Master's Program as part of a unit on what makes instructional technology attractive to online users.