Less than $10, Less than 10 minutes
As I have used my BSFL composting tower (my BSFL Condo) for several months, I realized that the original food that was being processed was being compressed and turning very smelly (anerobic decomposition). I needed some way to remove the older material without messing with the new food material and the current crop of BSFL. In other words I needed a way to remove the already created pudding.
Another need that I had was a way for the mature larve to crawl away from the food without ramps, paths, etc. that would just be hard for me to build.
So, in a fit of creativity, I considered what you see here. It is a five foot long piece of 4” pvc pipe that I purchased from Lowe’s. The ends are covered in test caps used to keep trash from entering exposed ends. By putting the caps on, and drilling some holes, I have accomplished a new form of DIY_BSFL_BIOPOD.

One end has two large holes drilled in the test cap. The top hole is meant to allow the momma fly to enter and ovipost near this entrance of the pipe. The bottom hole is a hole meant to allow mature larve to crawl up the pipe and exit and drop down into a container of leaves for them to pupate. The top hole is also large enough to use as a grip to pull the cap off to place food into the pipe.
To hold the pipe at an angle, I simply insert the pipe under the handle of a five gallon bucket and balance the weight with a brick in the bucket.

The bottom end of the pipe also has a test cover but drilled with numerous little holes. The little holes allows drainage of liquid and the entrance of air. Also, since the test cap lets in some light, it shuns the larve away from the bottom to some degree. The holes that do not have drainage, merely allows air to enter into the tube. Perhaps a draft is created as the material heats up and sucks air in.
Also, on the bottom end, the cap can be removed to push out some of the more mature, older food waste. The desire is that the larve have had their way with this and have since left it. The cap can also be a place where some eggs are laid, as you can see in the picture. I assume that the baby larve are small enough to enter through the drain/air holes.
The only problem that I have in this setup so far is the slowness of entering the food waste into the pipe. Taking a half a gallon of food waste and entering it into a four inch hole without spilling is a rather slow process. But this could be remedied with a little creativity.
The PVC pipe seems to be a good fit for our goals. It can withstand the food and the BSFL without chemical leaching. It can insulate rather well the contents from the outside weather (which would be good for winter time). It has a volume equivalent to that of the five gallon bucket. And the inside doesn’t seem to be as hot as the other containers as I don’t see them trying to escape from the food.