3M Marine Grade Silicone Sealant - White 3 oz Tube, High-Temp Non-Yellowing Flexible Seal

3M Marine Grade Silicone Sealant PN08017 is a high-temperature, non-yellowing silicone sealant formulated to create long-lasting, flexible seals above the waterline in demanding marine environments.

Built for boats and coastal projects, this 3 oz tube of 3M marine silicone delivers a resilient, moisture-cured barrier that resists sagging and discoloration. The formula bonds to many common substrates—bare and painted metal, fiberglass, glass, non-oily woods, certain plastics and abraded rubber—making it a versatile choice for general sealing, trim work, and small repairs on deck and cabin surfaces. It is intended for industrial or occupational use and performs best where exposure to heat and sun demands a stable, non-yellowing finish.

How does this silicone perform in hot, sun-exposed marine conditions?

The PN08017 formulation is designed for high-temperature stability so it maintains flexibility and appearance under heat and UV exposure. While no sealant is indestructible, this product resists sagging and yellowing better than many generic silicones, helping seals stay effective and discreet over time.

• High-temperature formulation reduces flow at elevated ambient temperatures.
• Non-yellowing chemistry preserves white finish under sunlight.
• Remains flexible to accommodate thermal expansion and movement.

What surfaces will this marine silicone adhere to reliably?

3M Marine Grade Silicone bonds to a wide range of above-the-waterline materials commonly found on boats and marine structures. Good adhesion depends on clean, dry, and appropriately abraded surfaces; avoid oily or unprepared plastics unless specified compatible.

• Bonds to bare and painted metals and aluminum trims.
• Adheres to fiberglass, glass and non-oily woods for trim and window seals.
• Works with many plastics and abraded rubber—test on plastics first.

How quickly does the sealant cure and how should it be applied?

This is a moisture-curing silicone, so curing begins as it reacts with ambient humidity. Skin-over time and full cure depend on bead thickness and environmental conditions; thin beads cure faster. For neat, durable joints use a properly sized nozzle, apply steady pressure, and tool within the product’s working time.

• Moisture-cure chemistry: cure time varies with humidity and bead size.
• Apply from the 3 oz tube using a standard caulking gun or manual application for small jobs.
• Tool or smooth bead promptly for optimal contact and appearance.

Is this product appropriate for underwater or structural bonding?

PN08017 is intended for above-the-waterline sealing and general marine use rather than submerged or structural applications. For below-the-waterline or load-bearing joints, choose a sealant specifically rated for immersion or structural bonding.

• Designed for above-the-waterline interior and exterior sealing only.
• Not formulated as a structural adhesive or for continuous underwater exposure.
• Consult 3M product literature for immersion-capable alternatives.

Who is this for: This 3 oz tube of 3M Marine Grade Silicone Sealant is aimed at marine professionals, boatbuilders, riggers, and serious DIYers who need a compact, travel-friendly sealant that resists heat and yellowing for above-the-waterline sealing tasks. It’s well suited for window trim, hatches, non-oily wooden fittings, metal flashing, and general maintenance where a reliable, flexible white silicone is required.