3M 05205 Marine Adhesive Sealant 5200 Black 3 oz Squeeze Tube | Permanent Polyurethane | No Gun Required | Weathering & Saltwater Resistant | Above & Below Waterline | Tack Free 48 Hr, Full Cure 5–7 Days

3M 05205 Marine Adhesive Sealant 5200 Black 3 oz Squeeze Tube — Permanent One-Component Moisture-Curing Polyurethane | No Caulking Gun Required | Flexible, Weathering & Saltwater Resistant | Above & Below Waterline | Tack Free 48 Hours, Full Cure 5–7 Days

3M Marine Adhesive Sealant 5200 Black (05205) is the same industry-standard permanent 5200 polyurethane formula in a black color, 3 oz squeeze tube that requires no caulking gun. One-component, high-strength, moisture-curing, gap-filling polyurethane that bonds aluminum, wood, gel coat, and fiberglass with a permanent, flexible, waterproof seal above and below the waterline. Weathering and saltwater resistant. Retains flexibility after cure. Tack free in 48 hours; full cure in 5–7 days. Permanent bond — separation after full cure requires cutting or grinding. Black. 3 oz squeeze tube.

Part Specifications

• Part Number: 3M-05205
• Product Line: 3M Marine Adhesive Sealant 5200
• Color: Black
• Size: 3 oz squeeze tube — no caulking gun required
• Chemistry: One-component, moisture-curing polyurethane
• Bond Type: Permanent — separation after full cure requires cutting or grinding
• Substrates: Aluminum, wood, gel coat, fiberglass
• Application: Above and below the waterline
• Cured Properties: Flexible, waterproof seal; weathering and saltwater resistant; retains flexibility after full cure
• Tack Free: 48 hours
• Full Cure Time: 5–7 days
• Also Available — 5200 Black: 3M 06504 5200 Black 10 oz Cartridge (caulking gun required)
• Also Available — 5200 White: 3M 06500 5200 White 10 oz Cartridge | 3M 05203 5200 White 3 oz Squeeze Tube
• Also Available — 5200 Fast Cure White: 3M 06520 5200 Fast Cure White 10 oz Cartridge | 3M 06535 5200 Fast Cure White 1 oz | 3M 05220 5200 Fast Cure White 3 oz

Black Color — When to Choose Black 5200

The 05205 uses the same permanent 5200 polyurethane formula as the white versions. Color choice is driven by the application and the desired appearance of the finished sealant bead:

• Below-waterline hull applications: Most production and racing hulls use black bottom paint or dark antifouling coatings. A black 5200 bead at through-hull fittings, transducer installations, and keel-to-hull joints blends with dark bottom paint rather than showing as a visible white line at the waterline or below
• Rub rail and rubrail insert bedding on dark hulls: Black rub rails and rubrail inserts on black or dark-colored hulls look cleaner with a black sealant bead at the rub rail base; a white bead would be visible if it squeezes out during installation
• Black-painted or dark transoms: Outboard bracket installations, transom drain plug bedding, and trim tab installations on black or dark-painted transoms where an exposed white bead would stand out
• Engine compartment and bilge through-hulls: Interior bilge, engine compartment, and raw-water through-hull applications where the sealant bead is not visible from outside but a dark color is preferred for a factory-finished appearance
• When white is the better choice: White hulls and topsides, above-waterline deck hardware on white or light gelcoat surfaces, cabin-side fittings, and any application where the finished sealant bead will be visible on a light-colored surface. See 3M 06500 5200 White 10 oz or 3M 05203 5200 White 3 oz.

3 oz Squeeze Tube — No Gun Required

• The 3 oz squeeze tube dispenses directly without a caulking gun — useful for single-fitting installations, remote locations on the boat where handling a full caulking gun is awkward, and repair jobs that don’t justify loading a 10 oz cartridge
• Apply by squeezing the tube directly; cut the nozzle tip at 45° to the desired bead size
• 3 oz is suited for single through-hull bedding, one or two deck fitting installations, a short rub rail section, or a spot repair to a below-waterline seam
• For larger jobs — full deck-to-hull seams, multiple through-hull runs, keel bedding — use the 3M 06504 5200 Black 10 oz Cartridge to reduce tube changes and lower cost-per-oz
• Reseal the tube tip between uses by folding and clamping the tube end; the 48-hour tack-free time means the nozzle tip will skin over slowly if recapped promptly

Permanent Bond — Critical Consideration Before Applying

• 5200 is a permanent adhesive sealant — once fully cured, joints cannot be disassembled without cutting or grinding the bond line, which damages bonded surfaces
• Verify all fitting positions, alignment, and fastener holes before applying — repositioning is possible for up to approximately 48 hours before the surface skins over, but becomes progressively more difficult as cure advances
• Typical permanent 5200 Black applications: below-waterline through-hull structural bedding, keel attachment, transducer installations on dark hulls, and rub rail base bedding on dark-hull installations
• If future disassembly may be required: use the serviceable 3M 4200FC White 10 oz (06560) instead — same polyurethane family, strong hold, but can be disassembled for maintenance without cutting or grinding. Note: 4200FC is available in white in this catalog; verify black availability directly with 3M if black color is required for a serviceable application.

Application Notes

• Surfaces must be clean, dry, and free of grease, oil, wax, antifouling paint, and loose material — wipe with acetone or isopropyl alcohol and allow to dry completely before applying; antifouling paint at the application area should be removed back to bare substrate for proper adhesion
• Apply to one or both surfaces and press together firmly; secure with fasteners or clamps during the 5–7 day cure to maintain joint position
• Moisture initiates cure — higher humidity and warmer temperatures accelerate surface cure; cooler or drier conditions extend cure time
• Full cure 5–7 days — do not stress the joint, immerse below the waterline, or load the bond until fully cured
• Uncured product: clean up with acetone or MEK. Cured product: must be cut or abraded for removal
• Wear gloves — uncured black polyurethane stains skin and clothing and is difficult to remove

Additional Information

• Vendor: 3M
• SKU: 3M-05205
• Product Type: Boat & Engine Maintenance / Adhesives & Sealants
• Color: Black
• Size: 3 oz squeeze tube
• Country of Origin: USA
• HS Code: 3506.10 (products suitable for use as glues or adhesives, put up for retail sale — verify for your import classification)

Frequently Asked Questions

Q: Is the 05205 Black the same formula as 5200 White?
A: Yes — same permanent 5200 polyurethane formula, different color. Cure times, bond strength, substrate compatibility, and above/below-waterline rating are identical. Color choice is driven by the application surface and desired bead appearance.

Q: Why would I choose black 5200 over white?
A: Black is preferred for below-waterline through-hull and keel applications on dark or black-bottom-painted hulls, dark transoms, and black rub rail installations where a white bead would be visible and contrast poorly with the surrounding surface. For white hulls and above-waterline deck hardware on light gelcoat, use 3M 05203 5200 White 3 oz or 3M 06500 5200 White 10 oz.

Q: Does the 3 oz tube need a caulking gun?
A: No — the 3 oz squeeze tube dispenses directly without a caulking gun. Cut the nozzle tip at 45° and squeeze to apply. For larger jobs requiring more product, use the 3M 06504 5200 Black 10 oz Cartridge with a standard caulking gun.

Q: Can 5200 Black be removed after it cures?
A: No — 5200 is permanent. Separation after full cure requires cutting or grinding the bond line and damages bonded surfaces. If there is any chance the fitting will need to come out for service, use a serviceable polyurethane sealant instead. See the 3M 4200FC White 10 oz (06560) — note that 4200FC is available in white in this catalog.

Q: How long before I can launch after bedding a below-waterline through-hull with the 05205?
A: Full cure is 5–7 days — do not immerse below the waterline until fully cured. Tack free in 48 hours means the surface has skinned over, not that the bond is at full strength. Cooler or drier conditions extend cure time beyond 5–7 days. Also remove antifouling paint from the bonding area before applying — 5200 must bond to bare substrate, not antifouling coating.