CRL 33S Black Silicone Sealant — Glazing & Waterproof Sealant

• Our Most Popular Sealant
• Plastic Cartridges With Screw-On Nozzles
• Available in Eight Colors
• 24 Month Shelf Life*
• 10 Year Limited Warranty

This is our most popular sealant! CRL 33S Silicone (SKU 33SBL) is a one-component, room-temperature curing, acetic-cure, 100% silicone elastomer that delivers professional-grade performance for glazing, window, and sanitary applications at a competitive price. No activators, stabilizers, or catalysts are required for optimum performance.


Basic Uses - CRL 33S Silicone is formulated for joining and sealing most non-porous building materials including glass, aluminum, stainless steel, wood, and many plastics. Ideal long-tail use cases: 100% silicone sealant for windows and storefronts, mildew-resistant silicone for showers and bathrooms, and low-temperature application silicone for refrigeration units. Surfaces must be properly cleaned and the sealant tooled for good adhesion. Cat. No. S1L2100 Primer may be required for some substrates.

Performance & Physical Properties - Wide operating temperature range: -80° to 400°F (-62° to 204°C). Can be applied outdoors as low as -35°F (-37°C). Key properties: 350 psi Tensile Strength; 120 psi Lap Shear at 1/8" (3 mm) thickness; Tear Strength 25 ppi. Suited for curtainwall joints, steel and aluminum windows, skylights, bathtubs, showers, and other sanitary installations. Mildew-resistant formulations (clear, white, translucent white, and tan) contain a fungicide for cured beads.

Limitations - Not recommended for structural glazing, insulating glass glazing, concrete and stone expansion joints, horizontal decks, patios, driveways, terrace joints with abrasion, submerged joints (pools/aquariums), plazas, decks, pavements, or on concrete, marble, limestone, lead-coated, copper & brass surfaces. Not suitable for painting or for surfaces with special protective or cosmetic coatings (mirrors, reflective glass, polyethylene, polypropylene). Remove all old sealant before applying new. See cartridge label and Specification Data Sheet for additional limitations.

Comparable Sealants - Dow Corning®: 999-A; 786; 732; 700; Glazing Silicone; General Purpose; Commercial Grade 100%; Tub, Tile and Ceramic, HVAC/R. Dap: 100% Silicone. GE®: 1200 Construction, 1000 Contractors, 1700 Sanitary. Tremco®: Proglaze, Tremsil 200, TremPro 644. OSI: HM-270. Pecora: 860, 863. Sika®