A lab scale continuous process solvent-based prepreg manufacturing machine (prepreg treater) is a useful tool for small-scale production runs carried out by research teams involved in various projects related to advanced composites. Such a machine can also be used in school laboratories for teaching purposes. However, industrial compact prepreg treaters available for purchase are prohibitively expensive.This document details the work done by undergraduate students at Western Washington University to design, develop, and qualify a modestly budgeted, solvent-based prepreg manufacturing machine to be used for investigation of new prepreg resin systems. The steps undertaken to manufacture the machine and qualify it are explained in detail and can be helpful to educational institutions that may have requirements of such a treater for research and/or teaching. DefinitionsPrepreg is commonly defined as a reinforced fabric that has been impregnated with a resin matrix. It is frequently used in place of a traditional hand layup for a number of reasons, including increased control over resin content, decreased scrap and mess, and generally improved reproducibility during processing.[1] Following impregnation of the pre-polymeric resin system into fibers, the prepreg is considered B-staged. At this point in processing, the resin has undergone a partial cure and begun to crosslink. As such, storage in freezers is required, to prevent further crosslinking of the material into a fully cured C-stage product. [2] Prepreg is manufactured primarily using two processes: solvent coating and hot melt coating. In the solvent coating process, fabric is threaded between metal rollers and run through a resin bath, then fed through a series of ovens to partially cure the material. Following a short cooling period, the prepreg is ultimately wound up at the other end of the machine into a roll, for ease of storage [3]. The resin in the bath is dissolved in a solvent, typically an alcohol or acetone, to reduce its viscosity and increase its ability to penetrate the fibers. The solvents are released as volatiles in large in-line ovens as a part of the process during B-staging. In contrast, to produce prepreg using hot melt coating, fabric is run through a carrier paper containing a fixed quantity of resin, followed by the application of pressure with heated compaction rollers. This simultaneously impregnates the fabric and B-stages the resin. The fabric is then cooled and the paper removed.