There are two basic ways to compost outdoors, a static bin (like the one my colleague David Priest made himself) or a compost bench.
There is(picking down a bucket – done!), but even if you follow Dave’s more involved designs, it has a downside. Static compartments are easy to install, but they need more work to maintain. If you, like me, are more of a “long-term lazy” type, the tumble style may be for you.
To break down evenly and help reduce the likelihood of attracting unwanted pests, your compost must be turned regularly. With a static wastebasket, this means that you take a shovel or a piglet and manually dig through and turn the compost. With a tumbler construction, you get to live out your wildest dreams as a competitor on The Price is Right, which spins the big wheel. Just take the edge and let it tear. Your price will be rich planting soil that is easier to maintain.
These directions will make a porpoise that is 3 feet wide and about 20 inches in diameter, for a potential of about 6.5 cubic feet (or just a shy 50 gallons) of compost.
If you already have the tools for the job, look at a total cost of about $ 60. You can compare this to off-the-shelf options for 50 to 100 gallons capacity that range in price from $ 100 to $ 300. You get more options for the actual size and look of the finished product, plus the sweet, sweet feel of performance.
Material list: eight 6-foot two-by-four, two 2-to-2-foot panels of 3/4-inch plywood, two 10-foot rollers of galvanized steel hanger, a lot of 1-1 / 4-inch wood screws, one 4 -foot piece 1-inch galvanized steel pipe, a set of hinges and a latch.
Tool list: Measuring tape, power drill, 1-3 / 8-inch spade piece, saw (circular or miter), brad nail (optional).
Step 1: Cut the body
First, take the eight two-by-four and cut them in half, leaving sixteen 3-foot pieces. Then take three of these pieces and cut them into thirds, giving you nine-meter-long sections. Now lay out all the boards and make a rectangle that is three meters wide with a width of sixteen two-to-four (56 inches) with the three pieces that you cut in thirds somewhere in the middle, sitting next to each other.
Step 2: Connect the cards
To secure the boards, I went with thin, flexible metal straps that you can attach to each card with wood screws. Lay a strap about 10 inches down from the top edge and then another 10 inches up from the bottom edge. Let the 6-inch strap hang from one end of both straps. You use the extra strap to secure the shape of the tumbler in place. For best results, keep the boards as close together as possible, using two screws on each two-by-four for a total of four screws per card.
After securing the first two straps, take two more 18-inch cable ties and connect the three 1-foot pieces on each side of the access panel to each other and to their longer connected cards. With these, you get in about 2 inches from the top and bottom edges of the entire unit. You will secure the three foot-long pieces in the center of the access door in one more step.
You can now assemble the board and stand up on one side. Hold the strap on the inside and pull the two ends towards each other to form a cylinder. Pull everything together neatly and unscrew and unscrew overlapping straps.
Step 3: Attach the side panels and make the door
Now on to plywood. Drill or cut a 1-3 / 8-inch hole in the center of each plywood panel. The easiest way to find the center point is to draw two lines, from each corner to the opposite corner. The point where they cross is the midpoint. I also took the opportunity to use the center point and draw a reference circle on each piece of plywood to place the porpoise body. A diameter of 20.5 inches was perfect for me.
After drilling the center hole, take one of your plywood pieces and center it on top of your upright cylinder. Screw plywood through each end of the disc. I used a brad nail to hold the boards in place and then loaded the screws. Turn the assembly over and repeat for the other end.
If you now have what looks like the world’s worst homemade TIE fighter, you’re heading in the right direction. For extra strength, I cut two pieces of two to four that are 3-1 / 2 inches long (making them 3-1 / 2 inches square) and drilled a 1-3 / 8 inch hole in the middle. I secured one at each end and lined up these holes with the ones in plywood. This will help prevent the plywood from wearing out when you spin in the Showcase Showdown.
To get the access door, straighten the three foot-long sections and secure them to each other with two 10-inch cable ties, about two inches from the top and bottom edges. Place the two hinges on one of the boards on the unlocked side, about 2 inches from each end. Center and add the latch to the second non-middle board. Now take your door to the tumbler unit and hold it in place. Attach the hinges and the locking receiver to the tumbler body. Once you have verified that your door is working properly, take two additional 10-inch cable ties and place them on the outside of the door, each centered between the hinges and the center lock. This helps the door to retain its curved shape when you open and close it.
Last step: Adaptation and assembly
You have options for the overall dimensions of the porpoises. You can cut the boards that form the body longer or shorter as desired. You can also change the number of cards you use in total to adjust the diameter of the Recycle Bin.
I recommend that you do not use boards that are wider than 3.5 inches (standard width between two and four), as your tumbler would start to become more square and defeat the more efficient mixing possibilities in the cylinder shape.
If the weight of the trash is an issue, you can get away with using one for four if you add a pair of metal strips around the outside of the tumbler to reinforce them. That would reduce the total weight by almost half.
The gaps between two and four should prevent the need to drill holes for air circulation, which you can normally do for other types of tumblers. If you end up with too much of a gap between the boards and feel that you lose too much material when you spin it, you just cling to a fine metal net in the porpoise body over the problem areas.
To make this a permanent installation, I would suggest using two 6-foot four-by-fours for mounting posts. Bury about 30 inches in the ground, with concrete, then drill a hole in each of the posts for your galvanized pipe. Slide the tube through the holes in the tumbler and each of the posts. Add pipe covers to the ends of the pipe and you are done.
For a long-term installation, consider treating the tumbler with a dark colored / sealing combination. The dark color helps to absorb and retain heat, which is more efficient for the composting process. The sealant gives your porpoise a longer life, which prevents deterioration of the weather and related moisture.
I wanted my tumbler to be mobile, so I made a saw horse-based mounting frame. I picked up two sets of sawdust mounts for five dollars each and used five six-foot two-by-four cut in half to make the legs and bridge. I added a 1-1 / 4-inch PVC coupling that was held down with a 1-1 / 2-inch pipe strap that was centered on each saw horse. Now you can pass the 4-foot galvanized pipe through one of the PVC couplings, then through each drilled hole in the pulley and again through the coupling on the other side. I have also added a pipe cap to the ends of the galvanized pipe to prevent it from sneaking out of the couplings.
An afternoon worth working on and you have your very own compost bench! Give it a few spins a couple of times a week and you’re good to go.