Converting 'dirt' to greensand

The sand left over after removing the clay from my dirt is at least as fine as the sand I am currently using, which may be blowsand.

My thinking is that since this sand is already in a clay matrix it may behave more like natural green sand after the debris and excess clay is removed.

I removed most all the clay from the first batch and added some back.  It seems to make a better green sand than that made with the same clay and blow sand.

Started aa 2nd batch iwhere I left just a bit more clay with the sand.   About 3/4 of it went through my window screen sieve after drying.  The rest went into the bucket to rotate in the concrete mixer.  But when I tried to temper it there was not enough clay.

OK it has occurred to me that I can test the green sand for clay to sand by weighing a small sample, washing out all the clay, drying it and weighing again.   They key is to weight dried sample prior to and after removing all the clay.  So the following procedure should work.

1. Take a dry sample of dirt and screen out the rocks and twigs.
2. Wash out all the clay.
3. Dry and weigh the sand.

That will give me a base line of clay to sand in the soil.  Then I can determine how many times I need to was the dirt to remove just the right amount of clay.

1. Combine dirt with water.  
2. Drain off clay once.
3. Test ratio of remaining clay:sand.
4. Drain off a 2nd clay.
5. Test ratio of remaining clay:sand.
6. Repeat till only sand is left.

At this point I should know how many times to rinse to leave a clay:sand mix suitable for green sand.  This presupposed that I let the experiment rest for a fixed time between mixing and draining.   Maybe use the drill to mix each time to ensure uniform mixing.   Maybe that can be eliminated later.