Okay, this should work...

A project log for 3D-Printed Water Distillation Doodad

This doodad transforms a 2L pop bottle and a .5L plastic bottle into a solar distillery for drinkable water. 02/10/2016 at 03:560 Comments

Redesign with a top and bottom collar going outside bottle. I think this is the ticket...

Will print in the morning!