My daughter was incensed that the music notes I printed for her did include a treble clef, but not a bass clef. I ran this through netfabb cloud repair and made it manifold. It came out quite well on my first attempt with "grape" (purple) 1.8mm PLA from Protoparadigm on a decently well-dialed in MakerBot Replicator. Original SketchUp file included.