So, despite moving thirty miles specifically to ensure that I could make it to my hackerspace more often... I haven't been there in over a week. Even more distressing, somehow the original design that I tried to 3D print couldn't be converted into working g-code -- openscad seems to have something against the rotate_extrude function, so I think that my idea of 3D-printing the bearing cup is probably going to have to be abandoned. To American Science and Surplus I go !

I have had a slight epiphany during my absence from work, and have come up with a far more workable solution than 3D printing to produce the turbine -- injection molding. Specifically, I'm planning on using a CNC autorouter to make the pieces below (the inner piece will be broken up into six flat plates, and only two of the six outer pieces are shown for demonstration purposes), then I will clamp them together into a cylinder and inject polyurethane foam. This will be followed by a layer of chopped fiberglass and resin, to create a lightweight but durable piece. As an added bonus, once I get the proof-of-concept prototype out of the way, I'll have a ready-made mold for finishing a production run. I might be a little overoptimistic right now, but I'm hoping to have a few of these built by the end of the summer.