PLA / PVA Spring Motor Demonstrator

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From time to time, I revisit older designs for various reasons. This project, the redesigned PLA/PVA Spring Motor Demonstrator, is a revisit and redesign of my original PLA Spring Motor Demonstrator: http://www.thingiverse.com/thing:402412. The new version is smaller in size and printed in only one color, but its most significant feature is that it was printed in place and fully assembled using PLA for the structure and water-soluble PVA for supports. After printing is complete, simply throw it into a water bath for a few hours, and it's ready to run with no assembly required. While I had heard of dual-extrusion printers before, I hadn't learned about PVA until I saw the release of the Ultimaker 3. After many discussions with my wife, and just in time for Christmas, I received an Ultimaker 3 Extended that included PVA filament. I'm not a fan of PLA "supports" because they tend to leave a rough surface at the point of contact with the component being printed. However, Cura slicer and Ultimaker have solved this issue by using PVA supports, which create remarkably smooth surfaces that don't show any visual hint that support was used. The first photograph shows from left to right: the original PLA Spring Motor Demonstrator, the redesigned PLA/PVA Spring Motor Demonstrator encased in PVA, and the PLA/PVA Spring Motor Demonstrator after its water bath. The following video showcases the PLA/PVA Spring Motor Demonstrator in action: The next video demonstrates the PLA/PVA Spring Motor Demonstrator submerged in a PCB etchant tank with bubbler, heater, and water, which I found greatly assists in dissolving PVA from tight spaces: