You know that spot between sleeping and awake where you sometimes have eureka moments? This was one of mine. I was dreaming about a rotary sieve and got this idea.
This is a harbor freight cement mixer. I’ve been using it for a couple of years to mix ingredients into largish batches of wild/native clay. Today, I added some heavy duty window screen over the opening and secured it with a ratchet strap. It worked magnificently! I dumped and added more water (through the screen) a few times.
I need to trim the screen and the end of the ratchet strap, and find a wider tub so I don’t loose as much.
This is my sandstone clay which has a significant amount of sandstone and sand in it. It’s murder on your hands, especially that first step with the large chunks of sandstone. Doing it this way seems to have cut my processing time by half and saved my hands.
I floated/sieved more sand out after this step but still, it’s a huge improvement. If I wanted to leave more of the sand it would have cut processing time even further.
Stirring the clay before adding the screen 
What was left after sieving and adding water a few times 
The sandstone chunks
