Previous Next PRIMER 394 Categorie: GLUE AND SEALANTS and WORKSHOPS. Primer 394 is a solvent-based preparator. It is used as a pre-treatment of nylon articles assuming the following use of a polyurethane glue. Descrizione USAGE: Nylon surfaces must be clean, free of dust, grease. Wait for the complete drying before applying a polyurethane adhesive. Ventilate the area during and after use.