provided herein is a system useful for producing polymeric coatings on substrates , by means of a spray that is produced from impinging a compressed gas on a mixture that comprises an organic polyisocyanate and an isocyanate - reactive component . when a coating is produced from two components in accordance with the invention , each component is metered to an atomizing nozzle through peristaltic pumps , which enable increased control over flow characteristics as compared with prior art methods , and which importantly also enables greatly - reduced levels of wasted chemical components and attendant alleviated need for the use of volatile or expensive solvents in equipment cleaning operations . uncured coating precursor material is allowed greater residence time on the target substrate prior to final cure using a system an process of the invention , which results in coatings having greater integrity over those produced using prior art equipment and methods , as well as reduced overall cost .