Karnak - 502MS Karna-Flex Sealant, 30oz. Tube

Compact and ready for precise roof repair tasks, the 30 oz tube of Karnak 502MS Karna‑Flex Sealant is your go-to sealant for tight details and quick touch-ups. This robust, rubberized formula maintains its elasticity, sealing joints and flashing components securely even when surfaces shift or weather conditions change. Designed for direct application via caulking gun, this small-size tube delivers a neat, concentrated bond—perfect for professionals who need dependable sealing without excess material waste.

Key Features

• Pre-packaged in a convenient 30 oz tube for accurate caulking-gun application
• Retains flexibility and adhesion through structural movement and temperature fluctuations
• Adheres effectively to clean, dry, or slightly damp surfaces
• High elongation and cohesive strength for resilient performance
• White color offers a clean aesthetic, though not suitable for asphalt substrates

Packaging: 30 oz cartridge (white only)

Application temperature: 40 °F to 120 °F

Coverage: approximately 75 linear feet per tube with a ¼″ × ¼″ bead

Service temperature (cured): 15 °F to 180 °F

Weight per gallon (reference): ~9.7 lb

Elongation: around 500% (caulk tube rating)

Tensile strength: approx. 40 psi

Low temperature flexibility: down to –40 °F

VOC content: under 490 g/L

ASTM-C-734 tested—no cracking; recovery minimum 75%

Long-term weathering: passes 1,000-hour accelerated exposure without cracking

White is not recommended over asphalt surfaces to avoid bleed-through

• Clean and dry the surface; while the product adheres to damp areas, removing excess moisture enhances bonding.
• Load the white 30 oz tube into a caulking gun and cut the nozzle to match the desired bead width.
• Apply a consistent ¼″ × ¼″ bead over roof penetrations, fasteners, or trim details—75 linear feet coverage per tube.
• For seams and larger splits, embed reinforcing fabric between two applications.
• Smooth the bead gently for proper adhesion and finish.
• Allow the sealant to cure fully before further exposure or coating.
• Clean tools immediately with mineral spirits and work in well-ventilated conditions.

Q: Why is the white version not recommended for asphalt?
A: White sealant is prone to asphalt bleed-through; use the black version for those surfaces.

Q: How far will one tube reach?
A: At a ¼″ bead, a single 30 oz tube covers approximately 75 linear feet.

Q: Can it stick to damp surfaces?
A: Yes. It bonds to both wet and dry surfaces, though cleaner conditions improve results.

Q: Is the cured sealant flexible?
A: Absolutely—flexes down to –40 °F and stays effective through temperature extremes.

Q: What substrates can it bond to?
A: It bonds to substrates including BUR, modified bitumen, metal, concrete, plywood, spray foam, and aged EPDM, TPO, or PVC.