Just a quick show 'n tell about my experience with
stereolithography.

The file SmallSTLPart1.jpg shows a model Pelton bucket that was
made directly from a Rhino 3D .stl file.  Though the finish
isn't exactly specular, it was good enough to prove that the
geometry arithmetic was accurate enough for my needs. 
A polished version of this part would work even better than did
the delivered part.  The underlying metal is solid; you can use
conventional metalworking tools to reveal a specular finish.

As you can see from the image and the inch scale, it measures
about 0.77 cc in volume.
The company charged their minimum fee and provided three parts.

The file SmallSTLPart2.jpg shows the part as idealized in CAD.

Send them your stl file for a quote.

--Winston