Reddit reviews Play Sand: Squeezable Sand That Never Dries Out, You Receive Only 1 Container

Doing a little research there are several ways to keep the sand together...

Using a layer of:

• Polydimethylsiloxane which is a clear organic silicon coat that you can add to keep and preserve the shape of the sand. Which is very cheap and easy to come by.
  
  or
  
  
• Sodium Silicate which is similar and cause the sand to stick and harden.
  
  And there is innovative breakthrough in sand technology, using hydrophobic chemicals they create sand that never gets wet, which you've seen for kids.
  
  They've also made sand that will stick together without the need of water, allowing someone to mold and shape the sand without water and not worrying about it drying out.
  
  They may not be world saving cancer cures, but people have come up with several different ways to modify sand. You're literally just speaking like an ass. If we can send men to the moon, give people their vision/hearing back, soar across the skies, play in virtual reality, create bombs that will blow up 100's of miles of land... then we can probably think of a way to move sand structure from a beach, into a building.