Compost Bins are a great way to let organic food items left over from home decompose outside. Growing up we always had one at home so I figured it was about time to make my own. I wanted to purchase one myself but I needed to take out some trees around the house and thought I should make one out of the left over wood.
The trees that I harvested were pine trees varying in 3-4 inches in diameter. I wanted to make the compost bin blend in with the natural environments and also to be small enough to were it wasn't an eye sore.
Teachers: This project would be great for teachers trying to convey Standard 19 of Technological Literacy (manufacturing technologies). "Manufacturing systems use mechanical processes that change the form of materials through the process of separating, forming, combining, and conditioning." The raw pine trees harvested can be replicated as harvesting natural materials in many world applications.
This specific project would be perfect for 6-8th graders learning about manufacturing systems and the process that follows a product being made. For reference:
Standard 19 (F): Manufacturing systems use mechanical processes that change the form of materials through the process of separating, forming, combining and conditioning.
Standard 19 (H): The manufacturing process includes the designing, development, making, and servicing of products and systems.
Standard 19 (J): Materials must first be located before they can be extracted from the earth through such processes as harvesting, drilling, and mining.
I hope you either learn from my process and/or decide to make one yourself!
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Step 1: Supplies
Pine tree sections (2.5 ft. long) x 10
Wood Screws (for structural support into the pine, 1.5" inches long) x 40
Wood Screws (for the frame, 1" long) x 16
Hardware Cloth (acts as a screen to hold waste)
Hand Saw / Band Saw (to cut the sections of the wood)
Drill (for slotting the screw holes)
Hammer (molding the hardware cloth and nailing the support together)
Nail Gun Pencil (for marking guide holes)
Razor Blade (optional)
Joint Pliers (optional)
Plastic Crate (optional)
Tie down strap with 8 small screws (optional)
***In the image there is an example of one of the half natural pine sections used. Not shown is the wood used for the support frame but I have images of that later in the project.
Step 2: Gathering Wood
Like mentioned above, I was cutting down trees in the pastor before our house to make the drive up to the house more open and less cluttered. Having a wood supply was no issue for my circumstances.
Try to find pieces of wood that are similar in diameter. You can cut down two small oak trees and have plenty of wood. If they are from the same cut, the better. That way you know they are not only fresh, but carry a consistent diameter.
Step 3: Cutting the Wood to Create the Outer Shell
This part is pretty straight forward. I lined up all my oak sections that I had cut and made sure that they were similar in length. If they aren't the same length, the outer shell of the compost bin will be jagged (which may be preferred depending on your design, which it was for mine).
I simply marked the center of the log and began to cut. I used a band saw to carefully cut the wood down the center. The cut does not have to be perfect because you can either sand away the excess material to make the inside of the bin clean, or keep it the way it is (gives an extra natural feel to the project).
Step 4: Creating the Frame
The wooden frame will act as a lifeline for this project. It is important that this is constructed properly so there are no gaps in the wood sections. You want a nice snug fit so not compost can leak out of the sides.
I measured the length of my wooden sections and simply made a box. I recorded the average length of each 5 piece section (shown by the dotted line; 21 inches) and cut away.
My measurements for the constructed frame were 18 inches tall and 21 inches wide. Depending on what you used as a frame, you will have different measurements.
Start to construct your frame and nail piece by piece until you have two large squares. One of these will rest at the bottom, while the other will be supported at the top of the bin. Because we wanted our overall height to 18 inches, and I used 2 cm thick wood slabs, I simply measured out 4 posts to be cut (cut 18 inches away from your board, then cut an extra 4 cm off, because each square support is 2 cm thick)
A partner will be handy in this process as I needed one to hold up my square supports to nail in the post. Once you have your cube made, the fun begins.
Step 5: Adding a Screen to the Base
The Hardware Cloth acts almost like a filter. This was that all the decomposed materials stay in the bin rather than forming into the ground. For this part of the project we will cut out a square shape that matches the frame, and proceed to nail gun it to the wooden supports.
Set aside some cloth if you would like to add a small plastic crate to your bin. I decided to do this last minute that way washing out the bin and carrying compost back and forth would be easier. Find the right size crate, and cut out a piece similar to what we did before. I used a hammer to justify the curves and make the wire have a nice tight fit.
Step 6: Creating the Pine Barrier
Hold your wood section up against the frame and mark the center of the rings (of the pine). Start by slotting a screw hole with a drill bit slightly smaller than your screw. I did this to relieve pressure off my thin support so it would not crack the wood. Once you have both of you relief holes drilled, screw in the screws. Each wood section should have two screws in them, one screw on the top frame support, and the other on the bottom.
You are going to do this for all 20 sections of the pine to create the compost bin.
An image is shown of what one completed side looks like, followed by two sides, and three sides.
Step 7: Creating Handles (Optional)
Because the compost bin was so heavy, I decided to add handles form an old tie down strap I had. I did not add supplies for this because it is an optional feature, but I used 8 thick screws that were about ¾ of an inch long.
Each strap was a foot long, and the ends of the strap that are screwed into the wood are folded over (for extra strength). After I cut the strap into two sections, I burned the edges to make sure they wouldn’t ruffle out over time. I slotted the screw holes with a razor blade because you cannot screw directly into the straps, it will jam up.
I carefully screwed each screw into place, then used a flat head drill bit and drilled them into the wood sections as I liked.
Step 8: Plastic Crate for Transporting Waste (Optional)
For those of you that will be making this and storing it far in your backyard, I thought it would be nice to show an alternative method of adding compost to your bin. I found an old plastic crate such as the one pictured to transport organic waste back and forth.This will also make cleaning the bin easier, if you ever decide to clean it.
I used leftover hardware cloth and cut out a square section to add as an extra filter. This can also be taken out very easily. Now all you have to do is carry the crate to your kitchen/porch, dump the waste, and carry it out to the bin.
Step 9: Finished Product
So there you go! Your very own compost bin. This build time took me about 9 hours to complete, I am no woodwork master by any means.
I hope this has been a project of interest for most of you! I do realize that natural materials will degrade over time, which was kind of the point. A compost bin that slowly degrades into itself, kind of cool if you think about it (besides the leftover screws and screens haha). Enjoy making this yourself and let me know if you have any comments or questions, thanks for reading!