TotalBoat Polyester Structural Repair Putty - Gallon | Fiber-Reinforced, Waterproof Structural Bonding

TotalBoat Polyester Structural Repair Putty (gallon) is a pre-thickened, fiber-reinforced polyester filler engineered for high-strength structural bonding and bulk repairs on boats and mixed-material assemblies.

Built for boatbuilding and demanding repair tasks, this polyester putty combines a high-quality polyester resin with long-strand milled glass fiber to deliver a robust, impact- and crack-resistant mass that holds shape as it cures. It’s intended for structural bonding—deck-to-hull joints, stringers, liners, bulkheads—and for filling large voids where strength matters more than a factory-smooth finish. The product arrives ready to mix with the provided MEKP catalyst and cures quickly into a dense, waterproof repair suitable for above- or below-waterline work. For cosmetic finishing, follow with a fairing compound and gelcoat or topside paint.

How do I use this putty for structural bonding on a boat?

Prepare mating surfaces by removing loose material, grease, and dust. Mix the putty thoroughly with 1–2% MEKP catalyst by weight (about 1% gives 15–20 minutes working time at 70°F); apply and shape before it sets. Clamp or support assemblies until initial cure completes.

• Mix thoroughly; use 1–2% MEKP catalyst (adjust for temperature and mass).
• Apply paste-like putty into joints, fillets, and large voids.
• Holds shape during cure—no sagging in bulk fills.
• Allow full cure before trimming, then overcoat for cosmetic finish if needed.

Can I use it below the waterline and on different materials?

Yes. The cured putty is waterproof and bonds well to fiberglass, wood, metal, polyester laminates and many cores, making it suitable for repairs above and below the waterline. It’s ideal when dissimilar materials must be joined with a structural adhesive.

• Waterproof when fully cured—suitable for underwater repairs.
• Bonds fiberglass, wood, metal, and core materials effectively.
• Good for hull-to-deck, stringer, and bulkhead bonding.
• Not designed as a final cosmetic fairing—use fairing compound for smooth finish.

What finishing steps are required after the putty cures?

Polish and finish depends on whether you need a cosmetic surface. For a smooth, paintable finish, apply TotalBoat Polyester Fairing Compound over the cured putty, sand to shape, then use gelcoat or topside paint. If leaving the putty exposed, treat the surface to prevent tackiness.

• Overcoat with polyester fairing compound for a sandable, cosmetic finish.
• After fairing, use TotalBoat Gelcoat with wax or Wet Edge topside paint.
• If not overcoating, add paraffin wax (4 oz per gallon) or PVA to cure surface skin.
• Sand after full cure to desired profile before topcoat application.

How does working time, mixing and safety affect my repair workflow?

Working time varies by mass and temperature; a 100 g mass with 1% MEKP at 70°F gives roughly 15–20 minutes. Use the included MEKP catalyst and increase or decrease percentage to lengthen or shorten pot life. Always follow protective equipment guidelines and ventilate the workspace.

• Standard guidance: 1% MEKP for ~15–20 min at 70°F on small masses.
• Increase catalyst for faster cure, decrease for longer working time.
• Wear gloves, eye protection, and respiratory protection as required.
• Dispose of waste and containers per local regulations.

Who this product is for: TotalBoat Polyester Structural Repair Putty is aimed at boatbuilders, professional marine repair shops, and experienced DIYers who need a dependable, high-strength filler for structural bonding, filleting, and filling large voids. It’s also useful for automotive, RV, and general construction repairs where long-strand fiber reinforcement and bulk-filling without shrinkage are required. If you need a surface-ready finish, plan to follow with a fairing compound and appropriate topcoat.