  We have produced large and highly-reflective open-cell PVC extrusions for the
NOvA neutrino oscillation experiment. The extrusions were sealed, instrumented,
assembled into self-supporting detector blocks, and filled with liquid
scintillator. Each Far Detector block stands 15.7 m high, is 15.7 m wide and
2.1 m thick. More than 22,000 extrusions were produced with high dimensional
tolerance and robust mechanical strength. This paper provides an overview of
the NOvA Far Detector, describes the preparation of the custom PVC powder, and
the making of the extrusions. Quality control was a key element in the
production and is described in detail.
