I am in the planning stage of a new FT bin. I am going to construct it out of wood and line the inside with fiberglass. I just read through alot of the FT's people have made but few tell of problems and failures in earlier designs.
Considerations:1. I want to use scrap wood I already have on hand, so the max length could not exceed 4 ft.
2. I have 15" X 15" collection tubs available and my future source for replacements (they are a little brittle) has no end in sight.
3. I plan to use PVC with embedded screws as harvesting rods. I am not sure if metal rods are easily available nor how difficult it will be to use ( work with) metal instead of PVC.
Based on the above I can construct a bin 45"L X 15" W X 24+" H. By my calculations this is a little over 9 cubic feet of bedding volume. Actual size may be a little different, there will be some empty space for collection bins etc.
My main concern is weight. The overall weight of moist bedding on on the harvesting rods making them difficult to turn. The weight of the bedding on the legs or support. (I do not want it directly on the ground/floor). Most importantly the OUTWARD pressure of the bedding against the sides and connections.
Some of this I can alleviate by wood strips around the outside of the bin, particularly under the harvesting rods. I'm not sure if I need bridges or supports across the middle of the bin inside.