The container is a 5-gallon bucket. The fins are made of Plexiglas which are held in place with regular angle braces, nuts and bolts. The fin design was inspired by the lowly clothes drying machine. I recently added the wire mesh as way to further promote the breakup of agglomerates.
After filling with dry powders, the bucket is closed and placed on a ball mill unit where it rotates (I usually leave it running overnight).
Given points 2 and 3 above, I am working on a better design...