Interlux Ultra-Kote Hard Antifouling High Copper Bottom Paint

For tough, long-lasting protection, Interlux Ultra Kote delivers a durable, hard finish that resists fouling in high-growth waters. This high-performance Interlux Ultra bottom paint is made to withstand heavy use, making it ideal for powerboats and racing vessels that demand a smooth, efficient hull. Its advanced formula provides excellent adhesion and wear resistance, ensuring season-long antifouling protection. Ultra Kote offers reliable defense against barnacles and algae while maintaining a sleek, fuel-efficient surface. Available in blue, black, green or red.

Protect your vessel with Interlux Ultra-Kote Bottom Paint, formulated to keep your hull free from fouling and optimized for performance. This hard, durable coating provides excellent protection against all types of marine growth, ensuring your boat maintains its speed and efficiency. Ideal for boats in high-fouling areas, Ultra-Kote offers a strong defense, keeping your underwater surfaces clean and smooth season after season.

The Interlux Ultra-Kote is a high performance antifouling paint that is perfect for areas that experience moderate to severe fouling. Designed to provide maximum performance, the high copper hard coating provides excellent long term protection from shell fouling, such as barnacles. Thanks to the fast drying formula Ultra-Koat allows you to paint and launch in the same day. Can be used on Fiberglass, wood, or properly primed still with the addition of color stability for a uniform look. Able to be used in fresh water, salt water, & brackish water.

Note: Green Ultra-Kote (Part Number Y3559U1) is not available to ship to California

Features:

• Works on Fiberglass, wood, and steel boats
• For use in Fresh water, Salt water, & Brackish water
• Fast dry formula
• High Copper
• Long term protection

Specifications:

• Pack Size: US Gallon
• Finish: Matte
• Recommended usage: All fouling waters
• Colors Available: Red (Y3449U), Green (Y3559U), Blue (Y3669U), Black Y3779U
• Drying time: Touch dry 1hrs; To launch 8hrs. @73° F
• Number of Coats: 2 coats, 3 on bare wood (first coat thinned)
• Coverage: 506 ft²/gal
• VOC: 327 g/lt

How to Apply Interlux Ultra-Kote Hard Antifouling Bottom Paint

Application Tips

• Mixing: Stir or shake contents thoroughly before use
• Thinner: Special Thinner 216 or Brush Ease 433
• Thinning: Thin only if necessary. Thin no more than 10% (except conventional spray). Use Brush Ease 433 if roller or brush drags during application
• Cleaner: Special Thinner 216 or Brush Ease 433

Applicators

• Airless Sprayer
• Pressure: 170-204 bar/2500-3000 psi
• Tip Size: .53mm /21 thou.
• Must be thinned 5-10% bu volume with Special Thinner 216
• Conventional Spray
• Pressure Pot: Pressure : 3.44-4.47 bar/50-65 psi (gun pressure); 10-15 psi (pot pressure)
• Tip Size: 1.83-2.2 mm/70-85 thou.
• Thin 10-15" with Special Thinner 216 for application by Pressure Pot
• Roller
• Use a 3/8" nap solvent resistant roller

Surface Preparation

• Good Condition
• Remove all traces of loose paint & contamination by sanding
• Sand using an 80 grit wet-dry sandpaper
• Remove sanding residue
• Poor Condition
• Completely remove all old antifouling paint
• For Fiberglass & wood use Interstrip 299E
• For Steel sandblast to a near white metal
• Bare Fiberglass Preparation
• Fiberglass must be properly prepared to prevent delamination
• Remove mold release wax using Fiberglass Surface Prep YMA601V or Fiberglass Solvent Wash 202
• Fill any surface imperfections with Interlux Watertite
• Once surface is properly prepared follow the application system below
• Bare Fiberglass - No Sanding System
• Clean following the above preparation procedure
• Apply one coat of Interprotect 2000E or Fiberglass No-Sand Primer
• Following overcoating guidelines for the primer, apply 2 coats of Ultra-Kote allowing appropriate drying times
• Bare Fiberglass - Sanding System
• Clean following the above preparation procedure
• Sand with 80 grade (grit) paper
• Remove sanding residue
• Apply at least 2 coats of Ultra-Kote allowing for appropriate dry times
• Bare Fiberglass - Blister Prevention System
• Clean following the above preparation procedure
• Sand with 80 grade (grit) paper
• Remove sanding residue
• Apply Interprotect 2000E to a thickness of 10 mils
• Apply at least two coats of Ultra-Kote unthinned, allowing for the appropriate dry times
• Barewood
• Sand with 80 grade (grit) paper
• Remove sanding residue
• Apply the first coat of Ultra-Kote thinned 10% with Special Thinner 216 or Brush-Ease 433
• If necessary, fill seams with Seam Compound Brown 30
• Apply 2 or more coats of Ultra-Kote unthinned, allowing for appropriate dry times
• Underwater Metals
• Do NOT use on aluminum
• Contact Interlux Technical Service Dept. 1-800-468-7589 for full information

Click here to download Interlux Ultra-Kote Application Guide

Frequently Asked Questions

What makes Ultra-Kote different from other Interlux bottom paints like Micron CSC or ACT?

Ultra-Kote is a hard, modified epoxy paint. It stays on the hull and doesn't wear away like an ablative. It contains 50–65% cuprous oxide, making it a high-copper option built for moderate to severe fouling conditions. Ablatives like Micron CSC are better suited for boats used frequently and hauled seasonally; Ultra-Kote is the stronger option for boats kept in warm, high-fouling water long-term, and carries a multi-season performance rating.

Can I apply Ultra-Kote over my existing bottom paint?

Yes, in most cases, as long as the existing paint is firmly adhered, in good condition, and not a soft ablative or graphite-based antifouling. You cannot apply Ultra-Kote over soft or ablative paints. When in doubt, consult the Interlux antifouling compatibility chart before overcoating.

Can I use Ultra-Kote on an aluminum hull or aluminum outdrive?

No. Ultra-Kote must not be applied to aluminum hulls, outboards, or outdrives. The high copper content will cause galvanic corrosion on aluminum. Use a copper-free antifouling specifically formulated for aluminum in those situations.

How soon after painting can I launch?

At 73°F, Ultra-Kote is touch dry in about 1 hour and ready to launch in 8 hours, so you can paint and launch the same day under normal conditions. Cooler temperatures extend those times. At 50°F, you'll need to wait about 12 hours before immersion.

Does Ultra-Kote lose effectiveness if the boat is hauled for winter storage?

This is an important distinction between hard and ablative paints. While Ultra-Kote carries a multi-season performance rating, hard paints like this can oxidize and lose some effectiveness when left out of the water for extended periods. Boaters who haul and store seasonally may be better served by an ablative. Ultra-Kote performs best on boats kept in the water for the long term.

Will the paint color stay consistent over time?

Ultra-Kote is formulated for excellent color stability, which is one of its advantages over some other high-copper paints. Some color fading at the waterline can still occur with extended immersion, but it won't affect antifouling performance.

Does paint buildup become a problem over time with a hard paint like this?

It can, over multiple seasons. Unlike ablatives, Ultra-Kote doesn't wear away; it accumulates. After several recoats, you may need to sand or strip the hull before repainting. Planning your maintenance schedule with this in mind will save labor down the road.

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