I built my flow through based on the 55 gallon drum design. I had a large trash can sitting around waiting to become a rain barrel but decided to make into a worm condo.
I used 1/2 ID conduit (3/4 OD)for the spacers. HD sells them in 10' lengths for $2. I wasn't until I drilled the holes that I realized I needed 11 two foot lengths of conduit. I could have saved $2 by only having to purchase 2 pieces of 10' conduit if I measured the spacing for 10 rods.
I wrapped the ends of the spacers with duct tape so that they would not slip out.
I opted to run the spacers east/west and have the opening on the south side to reduce the load over the opening. It will be a little more difficult scraping sided to side rather than back and forth. Here is a view from the inside.
Here is one looking at the opening. I didn't have a jigsaw so I used my Dremel tool with a cutting bit to make the opening.
It is loaded up with some newspaper ready for some finished compost, veggie scraps and a pound of worms. I will probably order the worms next week to give the 'condo' a breaking in period with the new furnishings. Total cost ~$6. :-)
I thought about doing my grating east/west as well, but I've never heard of anyone's grating tearing through their container, and the plastic of my bin seemed pretty sturdy. Plus, I felt like the extra difficulty in harvesting might not be worth it.
Keep us posted on the bin's progress. How many worms are you starting with?
I'm going to start with 1 pound of worms and let them multiply. I want to make sure if I make a mistake I'm not murdering 2+ pounds of worm$.
How has your bin going? Does it attract flies at all? I guess if it is outside it doesn't matter.
The bin only has a newspaper base and shredded newspaper now so there is no activity. It is currently in the garage but I will be moving it below the back deck and move it back into the garage during the winter. I'll let you know about the flies in a few months.
i like your bin idea. Have you thought of putting a couple of pieces of wet cardboard on the bottom? After manure, cardboard is a great bedding and food for the worms.I do not understand how you get the castings out of the bottom. Maybe you can explain that to me.
I actually have several layers of newspaper on top of the spacers. The theory behind the flow through systems is that you let the lower section of the bin build up with finished vermicompost as I keep adding layers of food and bedding. It will actually be 4-6 months before I harvest any compost. (probably longer as I will only be starting with a pound of worms).
I have a garden tine (fork) that I will use to scrape the finished compost from the bottom opening. Gravity should help push the contents downward as I harvest. I liked this system because I would not have to manually separate casting and worms/eggs.