permaculture

[William Bryan Evans <williamevans@home.com>]

try 1 meter or less in diameter
a meter or more in length
and a mesh size from approximately 4mm to 12mm 
angle of incline from zeroto twenty to thirty degreees or so. 
Think about it..the bedding material must also be similarly graded
for this to work at maximum efficiency.
a rotating sifter.
they work
get some sheet steel and some galv tubing' gas pipe make some discs to
support end s ooof cylinder/throw on some ribs to keep the discs inline
w/ each other..tubing goes down the center and acts as drive axle 
dont forgett the hardware cloth,,put some holes in the disks so bedding
passses thru/ and add some sheet steel collars on both ends to act as
well you figure it out
william evans