• Economical antifouling protection
• Apply over most other antifouling paints
• For fiberglass, wood, and steel boats
• Available in Black, Blue, and Red

TotalBoat Underdog is an affordable, solvent-based antifouling boat bottom paint for single-season protection in low fouling conditions. Ablative technology continuously releases fresh 24% cuprous oxide biocide while minimizing paint build-up. An unbeatable value for short-season boaters.

Cleaner / Surface Preparation Solvents

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

Cleanup Solvents

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

Thinner / Reducer Solvents

• TotalBoat Special Brushing Thinner 100, for brushing and rolling applications
• TotalBoat Spray Thinner 101, for spraying and cool weather brushing/rolling applications

Primer / Precoat

TotalBoat TotalProtect

Acceptable Substrates

Fiberglass, wood, steel/iron, and properly prepared previously painted substrates.

Available Colors

Black, Blue, Red

Surface Preparation

Bare Fiberglass or Gelcoat

• All bare fiberglass substrates need to be fully cured for at least 5–7 days prior to any surface preparation.
• The surface must be properly dewaxed, or amine blush must be removed prior to any further surface preparation.
• Wash the surface with warm water and a mild soap. Dry the surface completely.
• Dewax the surface very thoroughly, using TotalBoat Dewaxer & Surface Prep and clean cotton rags. DO NOT use synthetic rags. Change out rags as needed to ensure that all possible wax has been removed.
• Clean the surface several times in this method to ensure all wax and other contamination has been removed. This must be done thoroughly before sanding the surface, or it will likely lead to delamination of the paint.
• Allow the surface to dry completely.
• Mask off any areas that are not to be painted with Underdog antifouling paint.
• Sand the surface with 80-grit sandpaper to a dull, frosty finish.
• Remove any sanding residue by wiping the surface clean with a clean, lint-free cotton rag dampened with Dewaxer & Surface Prep solvent, then wipe with a clean, dry cotton rag.
• Allow the surface to dry completely before applying Underdog, as directed below.

Barrier Coat Application:

• Applying a barrier coat such as TotalBoat TotalProtect to bare fiberglass before applying antifouling paint is very strongly recommended to prevent osmotic blisters.
• Once the bare fiberglass has been prepared to this stage, TotalProtect can be applied as directed on the label, prior to applying Underdog antifouling paint.

Bare Wood

• Wood should be in good condition, dry, and free of grease, oils, tar, dust, wax, or other potential contaminants prior to sanding.
• Mask off any areas that are not to be painted with Underdog antifouling paint.
• Use an appropriate seam compound for use below the waterline, as needed, to ensure all seams are filled and smooth.
• Sand the wood smooth with 80-grit sandpaper until the surface is even and smooth.
• Vacuum away any sanding dust and wipe the surface clean with a clean cotton rag or cheesecloth dampened with TotalBoat Special Brushing Thinner 100, then follow with a clean, dry cotton rag.
• Allow the surface to dry completely before applying Underdog antifouling paint.
• Apply Underdog as directed below.

Previously Painted Surfaces

• Only apply TotalBoat Underdog antifouling paint to previously painted substrates that are in good, serviceable condition. Only apply Underdog over compatible antifouling paints.
• If the previous antifouling paint is in good condition, sand with 80-grit sandpaper, then wipe the surface clean with clean cotton rags dampened with TotalBoat Special Brushing Thinner 100 or TotalBoat Dewaxer & Surface Prep, changing rags frequently as needed, before applying Underdog antifouling paint.
• Previous antifouling paints in poor condition (flaking, chipping, or peeling) should be completely removed by sanding, scraping, or using a chemical paint stripper.

Bare Steel or Iron

• TotalBoat Underdog cannot be applied directly to any bare metals. Iron or steel must be properly prepared and primed with TotalBoat TotalProtect.
• Remove any loose debris or rust with a scraper or stiff brush.
• Sandblast or grind the surface until the entire surface is shiny, bare metal with a 2–3 mil profile.
• Immediately remove all sanding/grinding residue and apply TotalBoat TotalProtect, as directed below.

Applying Underdog Over TotalProtect

• Underdog can be applied directly to the TotalBoat TotalProtect either by using the thumbprint-tacky method, or once the barrier coat has cured fully and has been sanded with 80-grit sandpaper, as specified on the TotalProtect label.
• The thumbprint-tacky method is preferred, as the antifouling paint can create a chemical bond with the curing barrier coat, while saving time and a few extra steps.

Thumbprint-Tacky Method

• When the final layer of TotalProtect has cured for 45–60 minutes, touch the TotalProtect film with your thumb.
• If it does not stick to your thumb, but you can make a thumbprint, you are within the “overcoat window.” Apply antifouling paint.
• If the TotalProtect is still sticky (more than just tacky), or leaves TotalProtect on the fingertip, or still feels wet, then wait a little longer.
• If the TotalProtect is fully cured to a dry state and is firm to the touch, leaving no thumbprint on the surface, then wait 24 hours from when the TotalProtect was applied and follow the sanding method below.

Sanding Method

• Wait a minimum of 24 hours from when the TotalProtect was applied and sand the barrier coat with 80-grit sandpaper until the whole surface is uniformly smooth.
• Remove all sanding residue and wipe the surface with clean cotton rags dampened with TotalBoat Dewaxer & Surface Prep, changing out rags as needed, then follow with dry cotton rags.
• Allow any remaining surface prep solvent to evaporate completely prior to applying Underdog.

Application Conditions

• Best results are achieved when the substrate, air, and paint temperatures are between 50–90°F, and relative humidity is less than 90%.
• Do not attempt to apply Underdog when air, substrate, or paint temperatures are outside of this range, if at all possible.
• Cure rates and wet-edge times may be extremely long, or extremely short.
• If possible, avoid applying or curing the material in direct sunlight to avoid very short wet-edge times.
• Do not apply during times of high humidity, when rain, dew, or fog may affect application or drying.

Application Methods

Shake or Stir TotalBoat Underdog antifouling paint very thoroughly prior to dispensing and applying. Ensure there are no solids settled at the bottom of the can to ensure consistent and thorough antifouling performance.

Brushing / Rolling Instructions

• Thinning TotalBoat Underdog should not be required for most brushing or rolling applications. However, for wood substrates, thin Underdog roughly 25% only for the first coat, allowing it to penetrate and seal the wood.
• If thinning is desired, a maximum of 5–10% (6–12 ounces per gallon of Underdog) TotalBoat Special Brushing Thinner 100 can be added to help achieve the smoothest finish or increase wet-edge time. DO NOT add more than specified.
• TotalBoat Special Brushing Thinner 100 promotes the best flow, self-leveling, and working time for Underdog under most conditions.
• Below 60°F, TotalBoat Spray Thinner 101 can also be used as a thinner for brushing applications to promote a quicker tack-free time without compromising flow or working time.
• Two coats of Underdog are recommended for seasonal use.
• An extra 1–2 coats are recommended for application over bare substrates, around the waterline area, and any other areas with increased wear, such as leading edges of keels, skegs, or rudders.
• Brushes / Roller Covers: Only use solvent-safe brushes and roller covers. Only use 3/16" foam or nap roller covers. DO NOT use thicker roller covers with the intention to apply more paint; Underdog is designed to cure at a specified wet mil thickness. Applying it thicker may affect performance or cure.
• Prior to launching, allow Underdog to dry for the specified time based upon temperature:
  • 6 hours @ 90°F
  • 10 hours @ 70°F
  • 16 hours @ 50°F
  • There is no maximum amount of time that the boat can be launched after painting.
• Roll and Tip Method: Roll perpendicular to the waterline, then tip with a brush in the direction of the waterline while wet. Work a small 2’ x 2’ area at a time to maintain an even wet edge.

Spraying Instructions

• Underdog can be thinned with TotalBoat Spray Thinner 101 up to 10% (12 ounces thinner per gallon of Underdog) for spray applications.
• DO NOT thin more than directed. Use the minimum thinner needed to achieve desired properties.
• Actual thinner percentage depends on spray equipment and environmental conditions.
• Underdog can be sprayed using conventional or airless methods.
• Settings vary by application and technique. Recommended starting nozzle size is 1.8–2 mm.
• Apply thin coats; do not exceed specified mil thickness. Applying coats thinner than specified may result in insufficient protection or premature wear.

Maintenance

It is strongly suggested that the bottom of the boat be checked regularly to make sure it is clean and that no growth is accumulating. The self-cleaning nature of the Underdog coating is most effective when the boat is used periodically. Boats painted with Underdog should not be scrubbed or cleaned for the first six months in the water, and at intervals of not less than three months thereafter.

Warning!

RAGS, STEEL WOOL, OR WASTE SOAKED WITH THIS PRODUCT MAY SPONTANEOUSLY CATCH FIRE IF DISCARDED IMPROPERLY. IMMEDIATELY AFTER USE, PLACE RAGS, STEEL WOOL, OR WASTE IN A SEALED, WATER-FILLED METAL CONTAINER.

Personal Safety

Always use proper Personal Protective Equipment when handling, sanding, or applying this product. Refer to the TotalBoat Underdog Safety Data Sheet for more info. Only apply Underdog antifouling paint with good ventilation.

Application Data

Physical Data