CRL 33S Clear Mildew-Resistant Silicone Caulk Sealant

• Our best-selling silicone with special additives to resist mold and mildew
• 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: 33SMRC) is a one-component, room-temperature curing, acetic-cure 100% silicone elastomer that requires no activators, stabilizers, or catalysts. It provides mildew-resistant performance for interior sanitary applications and durable weatherproof sealing for exterior glazing and curtainwall joints.

Key applications - Designed for sealing and joining most non-porous building materials: glass, aluminum, stainless steel, wood, and many plastics. Ideal for windows, skylights, curtainwalls, tubs, showers, and other sanitary installations where mildew resistance is required. Cat. No. S1L2100 Primer may be required for some substrates.

Performance & operating range - Wide operating temperature: -80° to 400°F (-62° to 204°C). Can be applied at outdoor temperatures as low as -35° to 140°F (-37° to 60°C). Physical properties: 350 psi tensile strength; 120 psi lap shear (1/8" / 3 mm); tear strength 25 ppi.

Limitations - Not recommended for structural glazing or insulating glass glazing; concrete and stone expansion joints; horizontal decks, patios, driveways, terraces subject to abrasion; submerged joints (pools, aquariums); marble, limestone, lead-coated, copper, and brass surfaces; or surfaces with special protective coatings. Not suitable for painting. See cartridge label and Specification Data Sheet for additional limitations.

Compliance & certifications - Meets TT-S-001543A and TT-S-00230C (COM-NBS) Class A; ASTM C-920 (Type S, Grade NS, Class 25, Use NT, G, A); CAN/CGSB 19.13-M87. Meets FDA 21 CFR 177.2600 for certain food-related applications and is NSF Certified to Standard 51 for plastic materials and components used in food equipment. UL Recognized Component. Meets CARB 2003 VOC requirements and qualifies for LEED® credits.

Note: Uncured silicone may turn pinkish with UV exposure but will cure clear in 24–48 hours if stored and used as directed.

Product Warning:
Not recommended for the surfaces and applications listed above. Remove all old sealant before applying new. Check cartridge label and Specification Data Sheet before use.