3M 7000045778 Marine Adhesive Sealant Mahogany

Product Description

The 3M 7000045778 is a marine-grade adhesive sealant formulated for permanent, watertight bonds in demanding saltwater environments. Based on a flexible polyurethane chemistry, it cures to a tough, resilient seal that holds above and below the waterline. It absorbs stress from shock, vibration, and the natural swelling and shrinking of hull materials, keeping bonds intact over time. The sealant remains workable for up to four hours after application, allowing positioning and tooling with a trowel or spatula. It will not sag or flow in vertical or horizontal seams once applied. Licensed marine technicians and experienced boat builders are the primary installers of this product.

This sealant is suited for a wide range of structural and sealing tasks on recreational and commercial vessels. Documented applications include fiberglass deck to fiberglass hull, wood to fiberglass substrates, porthole and deck fitting installation, motor mounting on fiberglass transoms, hull seams above and below the waterline, centerboard trunk joints, stern joints, strut-to-planking connections, and deck housing installations. It is applied with a standard manual caulking gun using the 1/10 gallon cartridge format supplied in this SKU.

Key Features

• Permanent, high-strength bond that retains strength above and below the waterline
• Flexible cure absorbs shock, vibration, and substrate movement without cracking
• Excellent resistance to weathering and saltwater exposure
• Remains workable for up to four hours after application for trowel or spatula finishing
• Non-sag formula holds in vertical and horizontal seams without flowing
• Applies with a standard manual caulking gun for controlled dispensing

Compatibility

Designed for bonding and sealing fiberglass to fiberglass, wood to fiberglass, and related marine substrate combinations on boat hulls, decks, and structural fittings.

Installation Notes

Installation is typically performed by marine technicians or qualified boat builders. Surfaces should be clean, dry, and free of oils or loose material before application. Allow adequate cure time before immersing the assembly below the waterline. Follow applicable workplace safety guidelines for polyurethane adhesive sealants, including adequate ventilation during application.

Technical Specifications

• Color: Mahogany
• Container Size: 1/10 gallon cartridge
• Weight: 0.99 pounds
• Minimum Order Quantity: 12
• UPC: 00051135065020

Standard Information

• Brand: 3M
• Manufacturer Part Number: 7000045778