Mack came up with this one all his own and I have to say I was pretty impressed because it is a true feat of engineering. Everything we make these days is from pallets because on one income a project is much more worth doing if it is free. If I had known all it would take to make my husband happy would be to go to the dump every day and pick up free stuff, I would have had him quit his job a long time ago. But now being resourceful isn’t just fun; it’s necessary. We used to have one of those fancy drum-shaped plastic bins that you turn with a crank on a side, but it basically desintigrated when we tried to move it from the old house, and besides, we were looking for a more permanent structure here. So Mack designed this bin to suit our purposes, and it kind of turned out halfway between a bin and a heap. It’s kind of hard to explain so I’ll just give you lots of pictures.
So to start out, he took one pallet in relatively good shape. We had some plastic chicken-wire type fencing that the previous owners left in our backyard when they moved out; he just tacked that on using a staple gun. The idea behind the chicken wire is to have a double-layer of filtration (in addition to the pallet planks) to sift out the smaller product from the larger pieces of stuff inside. You only want to use the material that is furthest along and most broken-down, so filtering out the big chunks helps with that. The whole compost bin is going to be built on top of this first pallet, like a base, and you need to be able to access the area beneath the pallet to pull out the material that filters through. Unlike other compost bins that need to be cranked and turned, gravity is doing the work for you here. That's what the cinderblocks are for. You could use something higher if you wanted more space to work with underneath, but for us this is just fine. You can see in this picture that there is a flat board all the way across the ground beneath the pallet that can be pulled out to access the final product; more on that later.
You can already see in the picture above that panels are positioned on three sides, made of plywood. These are going to be the walls of the bin. You can just screw these into the pallet base directly, then use simple 2 x 4 boards as corner anchors. Here's a picture of my husband looking hot and attaching the sides:
And now for the final step: accessing your compost. As you can see here, Mack selected a clean piece of plywood in relatively good shape and made sure it was the right size to fit in between the cinder blocks.
He also positioned some 2 x 2 planks horizontally and vertically so that the board would slide more smoothly when pulling it in and out (rather than sliding directly across the ground). You can see that underneath here:
Having a lid helps of course, both with smell and keeping little critters out, but it also keeps the moisture in and helps the materials inside decay.