This bin has been developed by the Seattle Community Composting Education Program. It is ideal for a managed compost system where turning the pile is an important activity. The three bins allow for frequent turning and successive production. As soon as the contents of bin #1 are turned into bin #2, start a new pile in bin #1. By the time the organic material is turned into bin #3 it is greatly decomposed. It can be stored there until it is ready for use in the yard.
[Line drawing - Seattle Composting Bin]
This design features adjoining wood framed boxes that are sided with hardware cloth on three sides for good air circulation. The front of each box is made of sliding horizontal panels which can be removed to allow access to the pile for turning.
|18 foot 2 x 4s, pressure treated||2|
|12 foot 2 x 4s, pressure treated||4|
|(or 6 foot 2 x 4s, pressure treated||8)|
|16 foot cedar 2 x 6||1|
|9 foot 2 x 2||1|
|6 foot 2 x 2s||2|
|6 foot cedar 1 x 6s||9|
|36" wide, 1/2" hardware cloth||22 feet|
|3/8" carriage bolts, 4 inches long||12|
|washers and nuts for bolts||12|
|16d galvanized casement nails||3 pounds|
|8d galvanized casement nails||1/2 pound|
|1 inch staples for power stapler||250|
|12 foot sheet of 4 oz clear|
|8 foot sheet of 4 oz clear|
|gasketed aluminum nails for roofing||40|
|3" zinc plated hinges for lid||2|
|flat 4 " corner braces with screws||4|
|flat 3 " T-braces with screws||4|
Handsaw or power saw
Drill with 1/2", 1/8" and 3/16th inch bits
3/4" socket or open-ended wrench for 3/16th inch nut
Heavy duty staple gun and 1/2 inch staples
Safety glasses and ear protectors
1. Cut two 32" and 36" pieces from each of the 12 foot 2 x 4s. Butt end nail the four lengths into a rectangle. Do this until four of these rectangles are constructed.
2. Cut four 37" lengths of hardware cloth. Folding the edges over about 1 inch, stretch it across each wood frame and staple it onto the wood frames along these edges so that it tightly stretched on the frame. Set these frames covered with hardware cloth, the dividers for the bins, on the ground parallel to one another with their 36 inch side down. Space them 3 feet apart. Mark the centerline of the two frames that make the inside dividers of the series of bins.
3. Cut the 18 foot 2 x 4s in half to get four 9 foot lengths and mark centerlines on the two that will meet the inside dividers when they are laid across the top of the four frames.
4. Place two boards on top of the frames, or dividers, lining up the centerline marks on the respective pieces. Drill a 1/2" hole at each junction, centered 1" from the edge, and position the carriage bolts.
5. Turn the structure upside down and lay the third 9 foot board along the top, again lining up the center marks. Square all corners and drill four holes for the remaining carriage bolts. Tighten all bolts. Staple a 9 foot length of hardware cloth along what is now the back of the bin.
6. Cut four 36" pieces from the 16 foot 2 x 6 to make the slats that will cover the fronts of the bins. Rip cut 2 of these to 4 3/4" wide and nail them to the outside dividers and baseboard. Center and nail the two remianing full-width boards on the front of the inside bin dividers.
7. Cut the remaining 2 x 6 piece into a 34" length and rip-cut it into four 1 1/4" x 34" pieces. Nail the back runners to the dividers leaving a 1" gap for the slats. Cut the 9 1 x 6 cedar boards into 31 1/4" slats and set them into place.
8. Use the remaining 9 foot 2 x 4 for the back of the lid. A 9 foot 2 x 2 forms the front, and four 32 1/2" 2 x 2s form the end- and cross-pieces. Lay out all the pieces for position and check squareness. Then fasten corners with corner braces and put T braces where dividers meet the 9 foot boards.
9. Set the lid frame on the bin structure, brace side down, and center it. Cut wiggle molding to fit front and back 9 foot sections of the lid frame. Predrill the molding with a 1/8" drill bit and nail it to the top of the lid frame with 8d casement nails. Cut the fiberglass to fit flush with the front and back edges of the lid, overlaying the pieces at least on channel wide. Nail the fiberglass to the wiggle molding, predrilling nail holes on every third hump. Use gasketed nails.