Densyl Mastic is a cold applied self-supporting mastic. It is a petrolatum compound containing inert siliceous fillers and vegetable fibers.

Densyl Mastic is used for sealing, filling and caulking applications where a protective, waterproof and non-setting mastic is required. It can be used to contour tank bases and profile irregular surfaces. It is applied prior to the tape application and generally used in conjunction with primer, Denso Petrolatum Tapes or Denso Bituminous Tapes.