Pecora 890NST is a one-part, neutral-curing, ultra low-modulus silicone sealant that will not stain natural stone like marble and granite. 890 NST reacts with moisture in the atmosphere to form a durable yet flexible building sealant. Pecora 890NST performs quite well under dynamic conditions due to its ultra-low modulus, high extension - compression, recovery properties and strong adhesion to most substrates and accommodates long-term movement of +100-50% in properly designed joints. Harsh weather conditions, including rain, sleet, snow, sunlight, extreme temperatures, high ozone concentrations and/or exposure to intense ultra violet rays have very little effect on the ultimate performance of Pecora 890NST even after years of such exposure. Pecora 890NST is designed primarily for sealing expansion and control joints in precast concrete panels, architectural and natural stone, metal curtainwalls, perimeter sealing of doors and windows, Exterior Insulation Finish Systems (EIFS) and numerous other areas requiring a high-performance sealant. 890NST adheres quite persistently to concrete, natural stones, masonry, steel, fluoropolymer painted and powder coated aluminum, wood, vinyl and many other plastics, generally without need for a primer, and performs equally well in new or rehabbed construction.

Applications

• concrete
• natural stone
• masonry
• steel
• fluoropolymer painted and powder coated aluminum
• wood
• vinyl
• many other plastics

Limitations

Pecora 890NST should not be used in the following applications: 

• Sealing horizontal decks, patios, driveway or terrace joints where abrasion or physical abuse is encountered
• Below grade or sealing submerged joints or below the waterline in marine uses
• In totally confined or airfree spaces since moisture is necessary for cure
• In designs that will be painted after application of the sealant. (Sealant should be applied after painting is completed)
• In structural glazing applications
• On surfaces with special protective or decorative coatings without prior consultation with Technical Services. 
• With building materials that bleed oils, plasticizers or solvents, i.e. impregnated wood, oil-based caulks, some vulcanized rubber gaskets or tapes, etc
• In interior penetration firestop systems
• On surfaces in direct contact with food. For such applications, use of Pecora 860 silicone with FDA approval is recommended

Product Specifications