There are several good sources
online for how to build a
solar still. Videos, articles. I came across this text, and was really impressed:
http://www.builditsolar.com/Projects/Cooking/SOLRSTIL.HTM
I'm building a roughly 3x4 ft
solar distiller using a salvaged plate of glass. I am making the body from ferrocement (dyed black). The
water channel will be
concrete as well. I will use PEX tubing covered in something or another to prevent UV exposure/damage.
Fun stuff.