• Undercoat for 1- and 2-part topside finishes
• High-solids formula covers in a single coat
• Dries quickly and sands easily
• Flexible coating won’t lift or crack

TotalBoat Topside Primer is a premium one-part, high-solids, flexible undercoat for wood, fiberglass, and previously painted surfaces. Its formula fills small imperfections and covers completely in just one coat—even on bare wood. It dries fast, cures to a hard, sandable finish in 60–90 minutes at 65°F, and serves as an ideal undercoat for one- and two-part polyurethane and enamel topside finishes. Lead-free and chromate-free.

Cleaner / Surface Preparation Solvents

• TotalBoat Dewaxer & Surface Prep
• TotalBoat Brushing Thinner 100
• TotalBoat Spray Thinner 101
• Acetone (bare substrates only, recommended for oily hardwoods or bare white oak)

Cleanup Solvents

• TotalBoat Dewaxer & Surface Prep
• TotalBoat Brushing Thinner 100
• TotalBoat Spray Thinner 101

Thinner / Reducer Solvents

• TotalBoat Brushing Thinner 100 for brushing and rolling applications
• TotalBoat Spray Thinner 101 for spraying and cool-weather applications

Paint Strainer: Medium (fine acceptable but not necessary)

Acceptable Substrates: Fiberglass, wood, previously painted surfaces, epoxy

Available Colors: White, Gray

Surface Preparation

Fiberglass

• Allow bare fiberglass to cure 5–7 days before surface prep or priming.
• Wash with warm water and mild soap; dry completely.
• Dewax thoroughly using TotalBoat Dewaxer & Surface Prep and clean cotton rags.
• Sand with 220-grit paper. A DA sander may be used. Wipe clean with a lint-free rag dampened with a listed prep solvent.
• Allow to dry completely before applying TotalBoat Topside Primer.

Bare Wood

• Wood should be clean, dry (6–8% moisture ideal; under 10% acceptable), and free of grease, oil, or wax.
• Sand smooth in the grain direction with 180-grit paper; vacuum dust and wipe with a listed prep solvent.
• Apply TotalBoat Topside Primer as directed.

Previously Painted Surfaces

• Only apply over compatible solvent-based coatings in sound condition.
• Strip failing coatings to bare substrate.
• Wash with mild soap and water; rinse and dry.
• Wipe with listed prep solvent, allow to evaporate, then sand with 220-grit paper and clean again before priming.

Epoxy Surfaces

• Allow epoxy to cure 5–7 days before surface prep.
• Wash with warm water and mild soap to remove any amine blush; rinse and dry completely.
• Sand with 220-grit paper and wipe clean with a listed prep solvent; allow to dry before priming.

Application Conditions

• Apply when substrate, air, and primer temperatures are 50–90°F with relative humidity under 90%.
• Avoid direct sunlight and high humidity during application or curing.
• Out-of-range temperatures can significantly affect wet edge and cure times.

Application

• Stir or shake thoroughly before use for consistent finish and predictable dry times.
• Do not apply thicker than 3 mils wet film; excessive thickness can trap solvents and leave the film soft.
• Allow TotalBoat Topside Primer to dry 10 min @ 90°F, 30 min @ 70°F, or 1 hr @ 50°F.
• Scuff-sand between coats with 220–320 grit once the film sands to a fine powder.
• Do not solvent wipe within 12 hours of applying the previous coat.
• Minimum recoat time: 1 hr @ 90°F, 2 hrs @ 70°F, 4 hrs @ 50°F.
• Use White primer for light colors and Gray primer for dark or bold colors.

Application Methods

Brushing / Rolling

• TotalBoat Brushing Thinner 100 provides optimal flow and leveling.
• Below 60°F, use TotalBoat Spray Thinner 101 to improve tack-free times.
• Add only 5–10% thinner as needed. Over-thinning extends dry time and increases drip risk.
• Use high-quality natural bristle brushes or 1/8" foam/mohair rollers. Avoid nap rollers that shed fibers.
• “Roll and tip” method (vertical roll, horizontal tip) yields smoothest results.

Spraying

• Thin 10–20% with TotalBoat Spray Thinner 101. Use the minimum thinner needed for flow and dry.
• Airless: ~170 bar / 2500 psi, 0.33–0.41 mm tip
• Pressure Pot: 50–65 psi (gun), 8–10 psi (pot), 0.89–1.4 mm tip
• Siphon Cup: 50–65 psi, 1.5–1.8 mm tip

Application of Topcoats

• Compatible with both one- and two-part topside finishes.
• Not designed as a stand-alone product; must be overcoated with an appropriate topcoat.
• After curing, sand and clean before applying topcoat according to manufacturer’s instructions.

Personal Safety

Always use proper PPE and ensure good ventilation. Refer to the TotalBoat Topside Primer Safety Data Sheet for details. Each color has its own SDS—confirm the correct one before use.

Warning

Rags, steel wool, or waste soaked with this product may spontaneously catch fire if discarded improperly. Immediately after use, place in a sealed, water-filled metal container.

Application Data

Physical Data