Spin-casting liquid mixtures followed by in situ polymerization offers an elegant and inexpensive method of generating front surface paraboloidal mirrors of almost any focal length, aperture, and on- or off-axis character, requiring no post polishing. Mirrors have been made from a variety of substrates including epoxy-composite mixtures, with focal lengths ranging from 2 to 80 m, and apertures from 5 to 76 cm. The goal of this project was to make spin-cast mirrors for use as reflectors, telescopes, and cat’s-eye retroreflectors in open path Fourier transform infrared (OP/FT-IR) spectrometry. These mirrors were designed for portable outdoor use, and thus have been optimized for maximum ruggedness and mechanical strength, and minimal mass, coefficient of thermal expansion, and cost. After spin-casting, the only preparation prior to silvering is a thermal post-cure. Results are presented giving details of the materials, hardware, and procedures used to spin-cast paraboloidal mirrors.