Seam & Bedding Compounds / Putties

What Are Marine Seam & Bedding Compounds and Putties?

Seam compounds, bedding compounds, and marine putties are specialized sealants designed to fill, waterproof, and protect the joints, seams, and hardware connections found on boats, yachts, and RVs. Whether you're sealing the planks of a classic wooden hull, bedding deck fittings, or protecting keel joints, these products are the frontline defense against water intrusion — and ultimately, against the kind of structural damage that can sideline a vessel for an entire season.

The concept is ancient: seam and bedding compounds trace their roots back to tar and tree sap used by early boat builders to keep water out of planked hulls. Today's formulations are far more advanced, engineered to flex, adhere, and resist UV exposure, saltwater, and the constant thermal cycling that marine environments demand.

Why Seam & Bedding Compounds Matter

Every boat has dozens — sometimes hundreds — of potential leak points: hull-to-deck joints, keel bolts, through-hull fittings, shafting log openings, hatches, cleats, and rubrails. Bedding compounds are applied between two mechanically fastened surfaces to create a watertight, long-lasting seal at each of these critical junctions. Without the right compound in place, even a well-maintained vessel can develop slow leaks that lead to rot, delamination, or corrosion over time.

Choosing the right product means understanding what the joint demands. Key considerations include:

• Location: Is the joint above or below the waterline? Underwater applications need compounds that remain flexible and durable after prolonged immersion.
• Flexibility vs. strength: Polysulfide compounds offer excellent flexibility and grip for moving joints, while polyurethane formulas deliver near-permanent adhesive strength ideal for hull-to-deck or keel joints.
• Removability: If a fitting may need to come off in the future — a cleat, a transducer, or a thru-hull — choose a compound that won't bond so aggressively that disassembly causes damage.
• Surface compatibility: Wood, fiberglass, metal, and canvas each interact differently with various compound chemistries, so always confirm compatibility before application.
• Paintability: Some compounds can be topcoated with antifouling or deck paint; others cannot, which matters greatly for below-the-waterline work.

Interlux Paint: A Trusted Name in Marine Seam Compounds

Interlux Paint is one of the most respected names in marine coatings and sealants. Interlux's seam and bedding compounds include purpose-built formulations for wooden boat construction, such as their well-regarded seam compounds specifically designed for filling seams in wood boat bottoms and keel joints that flex, remaining durable and flexible after immersion to absorb the natural expansion and contraction of planks. With a heritage stretching back to 1881, Interlux has built its reputation on delivering high-performance marine solutions trusted by boatbuilders and weekend sailors alike.