Check the listing for details. Densyl Mastic - Petrolatum molding and filler mastic. Condition: New. Listed at 359.85 USD. 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. Packaging - 6 each 6.6lb blocks Excellent sealing properties No VOCs Will adhere to metal, PVC, polyethylene and concrete Not effected by water, acids and salts Easy application Inert and environmentally stable Minimal surface preparation (SSPC SP 2-3) Meets AWWA C217 Standard.