[adolph]

> generally want a permanent result

I've often thought Tibetian-style colored sand mandalas would be a fun way to use such devices.

Of course, you'd need a lego-sorter-style device to separate the sand into different colors afterward.

[Doxin]

> Of course, you'd need a lego-sorter-style device to separate the sand into different colors afterward.

Well that nerd-sniped me. Maybe a very small vibratory feeder so you can handle individual sand particles? Would require the sand to be fairly homogenously sized, but that's nothing some sifting can't fix. One of those usb-microscopes for checking sand color perhaps? Then you get to the point where you want it going fast, which might be tricky...

[adolph]

Maybe something similar to microfluidic devices but using acoustical vibration to transition sand in and out of a non-newtonian fluid state.

To the degree that different colors of sand have different physical properties I wonder if it would be possible to use differences in vibration and/or electrostatic properties to sort as a whole rather than evaluating each grain.

https://physics.stackexchange.com/questions/479163/what-kind...

[fmajid]

Probably a better fit for a 3D printer with the hotend replaced with a screw pump.