Our Vermitopias are built with a wooden frame -- mostly 2x4, with 2x6's for the rope supports. This has started to decompose (after 3-4 years), so we're starting to redesign the bin to have a metal frame. We'll put this up on the web once we've got a few built.

Here's hopefully enough information to build yourself a vermitopia with a wooden frame, like ours:

These were made in pairs; it took two people two 6-8 hour days to make two bins from start to finish.

materials
Our bins were made of recycled 3/8" plywood, screwed to a 2"x4" frame, with a 2"x6" to string the ropes through. None of the wood was treated. After assembly, it was primed, then painted with three coats of exterior latex paint. The rope bed is made of 200' of 1/4" braided nylon rope, and a few 1" diameter air holes were drilled in each panel, covered with a fine mesh stapled and painted on. We used re-used wood and surplus (free at the dump) paint.

The plywood sides and lid can be efficiently cut out of 4'x8' plywood sheets as follows:
Each bin needs:

• two 24"x94+3/4" sheets -- "I" in the diagram
• two 16"x94+3/4" sheets -- "II" in the diagram
• two 24"x48" sheets -- "III" in the diagram
• two 16"x48" sheets -- "IV" in the diagram
• one 4'x8' sheet for the lid
• and probably another 4'x8' sheet for the floor.

To put the bin together, use the two "I" pieces as the front and back, on top; the "II"s as the front and back, below; the "III"s as the sides, on top; and the "IV"s as the sides, below. Look at those pictures again.

The rope is strung through holes drilled every 2" in the center 2x6, so the rope traverses each side 23 times. Two lengths of rope, one for each side, are used. To install the rope in each side, string one end of a 100' length through one of the rear corner holes, then tie an overhand knot in it. "Sew" the rope between the 2x6's, so the rope is travelling straight across the bin, not at an angle. Then tie another overhand knot after it comes out one of the holes in the center front of the bin. Make it as absolutely tight as you can -- string it through, then use some tools to pull out more slack in each length (like tightening your shoelaces), and tie it off tighter. Look at the pictures on the Methods page again.

The whole thing is framed with 2x4, with the plywood screwed on the outside. The only part of the frame that is exposed to the outside is the middle section, between the I and IIs, and between the III and IVs. This middle section is 2x6, and is what the rope is strung through. Look at the pictures.

The bottom panels on the front (the IIs in front) are on hinges, to allow harvesting out the bottom. The lid hinges on to the back of the bin, and needs some sort of framing also (to keep it from warping). We used 2x2 around the outside.

Underneath the ropes there are guides (2x2s nailed to the frame) to allow a screen to be slid underneath to catch the falling castings and allow easy harvesting. The floor beneath this is sloped to allow drainage, with a drainage hole covered by 1/8" hardware cloth. (keep out them mice!) Our floors were made of four pieces of 1/4" plywood to allow a center drain. We haven't included instructions for this because we think it'd be easier all around just to have one sloped piece of plywood -- when the floor needs to have debris scraped off of it, shovels get caught on the joins in the pieces. It's also trickier to construct than the rest of the bin. Sorry, no pictures.

Hope this helps. If you're in the area, and want to come see them, let us know. Again, we suggest this basic design, but making some sort of metal frame, so the bin doesn't start to fall apart after three or four years.

To get your bin started,, lay down a few layers of cardboard on top of the ropes, then start composting. What we do is put in a good mix of stuff six inches deep that will hot compost well, then once that is composted add the worms and begin feeding the worms. You could start right off with worms if you added sufficient amounts of bedding. The cardboard will decompose fairly rapidly, by which time the compost on top should be holding together well enough.

What's going to break first, and when? We've had around 26 bins in operation for about five years now. Here's how the different pieces hold up:

• the plywood panels require some replacement. The upper panels, that have compost sitting against them, break in places, but not as much as the frame. They've held up pretty well. The lower panels on the harvesting chamber, that aren't generally in contact with compost, are doing just fine. About a quarter of our bins have needed new panels.
• the 2x4 frame gives the most serious problem. The corner posts, that are sitting against the compost, and the top front 2x4, which bears weight when feeding and turning the bins, are rotting seriously in many bins. The screws that hold the plywood and the lid hinges on pull out of the wood when it gets bad. About a third of our bins need some 2x4's replaced or reinforced.
• the 2x6 rope support has broken in a few bins -- split lengthwise along the line of holes. This is the hardest to repair. About a tenth of our bins have had this break.
• the ropes hold up great. No problems, no replacement necessary. Make sure its installed tight enough so the compost doesn't sag down! Ours sag only an inch or two with a full bin of compost on top of them.
• the lid hinges can get pulled out of the bin if the wind blows a lid over backwards, or just if the 2x4 they're screwed into decomposes enough. To reduce stress on them, align them well, keep them oiled, and don't let compost get up between the lid and the bin right next to the hinges. A rope can be installed to keep the lid from going over backwards. Almost half our bins have needed new hinges.
• the lower door to the harvesting chamber can have problems if not cared for well. If the hinges are unhappy, they will get misaligned or pull out of the wood. A bit of warping in the wood can allow enough space for mice to squeeze through into the bottom chamber, despite latches on either side. Almost half the bins need repairs made to the hinges or latches to allow it to close properly.