Making radial impellers for turbines in any size by printing them in sections. The sections can be glued to a flat plate. In the pictures above a CD is used as the base for the impeller and additionally the gaps between the small segments are welded by a soldering torch. Have rotated it with a Dremel up to 20000RPM with no problems. Use hot glue to balance it. Careful when running it: weare protective glass! The parametric 3D model is public at https://goo.gl/QBuZ6H - slice it without tops nor bottoms. Hope people share their finding on housing design and finding the best aerodynamic parameters. Can make dust cleaners and wind mills for collecting energy... los of fun...