There was a question on how to create the water tight seal.. here is a piece of aluminum being machined on the Cheap X1 Mill conversion project. The aluminum acts as a flange between the PVC housing and the lexan plate. The aluminum is always attached to the PVC, and the lexan can be bolted and unbolted from it. An Oring sits in the grove just inside of the screws to provide the water tight seal. 

The O-Ring is not shown the picture below.