This Instructable shows how to build a trommel (rotary screen) for sifting compost or shredded leaves. The purpose of sifting is to separate coarse unfinished compost materials from the finished product or to separate out trash and debris from other organic materials before use in the garden. My city has trucks that go around sucking up all the leaves in the fall. These leaves are then placed in a huge pile and allowed to decompose. I can go get decomposed leaves from them as needed but they often contain trash and rocks that need removed so I'm planning to use this trommel to sift that material as well as compost. Sifting also makes organic materials appear more uniform which is desirable if you are using them as a top dressing or mulch.
Step 1: Materials
- 1/2 inch hardware cloth
- two large surplus bicycle rims
- 4 rollers and bolts to attach
- a little over 8 feet of dimensional lumber
- misc. wires for connecting the hardware cloth to the rims
Step 2: Remove the spokes from the rims
The fastest way is to cut them if you have some really strong wire or chain cutters. I used a really ancient fencing tool and that worked great! NOTE: You may also want to save the spokes to make plant markers
Step 3: Cut the hardware cloth to fit inside the rims
My rims (inside) measured about 21.4 inches in diameter so multiplying 21.4 x pi gives me a 67.2 inch minimum length. Add about 4 inches for overlap of the seam and cut at about 71 inches. I used standard 36 inch width hardware cloth.
Step 4: Attach the hardware cloth to the rims
Place the hardware cloth inside the rims and attach with wires through the spoke holes. I used plastic coated #14 household electrical wire. To fasten the seam of the tube I used #18 wire. (Be careful not to over tighten the wire or the wire will break.) Make sure the wire on the outside of the rim is lying flat so that the rollers don't bump over it.