Waterlox MARINE Sealer Application Guide

Waterlox MARINE Sealer is an exterior base/sealer coat for use with the MARINE finishing system. It is the same Tung Oil and resin composition as our ORIGINAL formula, for use as a sealer in exterior, direct sunlight/UV projects as a sealer only and prior to using Waterlox MARINE Finish in either High Gloss or Satin Sheen.

Getting Started

What You’ll Need


  • Chemical resistant gloves and eye protection (e.g.: safety glasses and/or goggles), hearing protection (if using buffing equipment).
  • NIOSH/MSHA-approved respirator during application (for organic vapor).
  • NIOSH-approved dust mask for sanding (if sanding to bare wood).
  • Read and carefully follow label instructions, guidelines, warnings and cautions.


  • Vacuum, broom and clean, lint-free rags.
  • Paint thinner or mineral spirits.1
  • Painter’s tape.
  • Box fan(s) to insure cross-ventilation and adequate dry.


  • One gallon covers approximately 500 square feet per coat
  • One quart covers approximately 125 square feet per coat
  • One 2 fl oz bottle covers approximately 6 square feet per coat


Not recommended for use with a roller.

For Large Projects:

  • An 8-12″ lambswool applicator and a paint pan large enough for chosen applicator.
  • A quality natural bristle brush or paint pad recommended for use with oil-based finishes for cutting in edges.
  • Abrasive pads for sanding and smoothing between coats (if necessary):
    • Maroon pads or surface preparation pads (SPP pads) are recommended.
    • Also 320-grit sandpaper, 0000 steel wool or other equivalent abrasive.

For Small Projects:

  • A quality natural bristle brush, lambswool hand pad or paint pad recommended for use with oil-based finishes.
  • Abrasive pads for sanding and smoothing between coats (if necessary):
    • 320-grit sandpaper, 0000 steel wool or other equivalent abrasive.
Surface Preparation


Waterlox MARINE will alter the appearance of the wood. Proper testing of the entire process should be completed before beginning.

  • Not recommended for use on new pressure-treated wood (requires a 6 – 8 week weathering period) or lumber that is water-repellent treated (requires a minimum 12 month weathering period).
  • Always remove any mildew, fungi, or nail rust prior to application with either oxalic acid or a bleach solution. Always clear-water rinse the surface after cleaning.


  • Surface preparation is the most important step; follow proper steps and grit sequences. For floor projects, consider hiring a professional who follows the accepted NOFMA/NWFA procedures for this step. All old finish must be removed and a NIOSH-approved dust mask should be worn during sanding. To maximize penetration, final sanding should be done with 80-120 grit. As with any penetrating oil, Waterlox MARINE Sealer will highlight sanding mistakes and imperfections.
    • Other acceptable methods of preparing weathered wood include power washing, oxalic acid, TSP (trisodium phosphate), and liquid bleach. Follow instructions provided by the manufacturer and always clear water rinse the wood surface and let dry a minimum of 48 hours before applying the finish. If there are any glossy patches or mill glaze, scuff sand those areas with 60 – 80 grit sandpaper and wipe clean.
  • Vacuum the surface thoroughly with and across the grain to remove as much sanding dust as possible, including all surfaces that could hold dust.
  • Lightly dampen a rag with mineral spirits or paint thinner and wipe the wood surface to pick up any remaining sanding dust. Allow the mineral spirits to evaporate (15-30 minutes) before applying.1
  • Tape off or cover any surfaces not being coated.
  • Perform any other preparation steps (e.g. stain) See the Stain and Waterlox guide for more information.
Application and Product Handling

Product Handling

Waterlox MARINE Sealer does NOT require shaking, stirring or mixing.

Application Steps

For best results:

  • Apply when surface and air temperatures are between 45° F and 90° F (7-35° C).
  • Saturate all end grains well and apply in the direction of the grain.
  • Moisture content of wood should be below 18%.
  • Do not apply in direct sunlight or when surface is hot to the touch.
  • Do not apply when rain or dew is expected within 4 hours.
  1. Pour out the amount of product needed for the first coat.
    • If working from a previously opened container, straining through a medium to fine mesh paint strainer may be required.
  2. Apply Waterlox MARINE Sealer liberally with the grain at the recommended spread rate.
  3. Allow to dry for 24 hours.
  4. For soft woods (e.g.: Douglas fir, white pine, yellow pine, cedar, etc.) Repeat steps 1-3 and apply a second coat of MARINE Sealer, or if using H2OLOX® products for your final finish coat(s). DO NOT SAND after the first coat of Waterlox MARINE Sealer.

Application Procedure

Large Projects:

  1. Clean the new, unused applicator with painter’s tape, lint roller, in the dryer or with a vacuum before starting.
  2. Pour out the Waterlox MARINE product into a paint tray.
  3. Dip the applicator fully into the paint tray to saturate it.
  4. Following the grain, pull the applicator (spread the finish) toward the opposite wall evenly. Hold the applicator with light pressure and at a slight angle to maintain a wet edge.
    • To avoid lap marks, maintain a wet edge by overlapping sections previously finished by several inches. Be sure to feather the finish at every start and stop.
  5. When cutting in edges do not work more than 5-10 feet from the field-applied finish.

Small Projects:

  1. Clean the new, unused lambswool applicator or pad with painter’s tape, lint roller, in the dryer or with a vacuum before starting.
  2. Pour out the amount of finish needed for the job or dip applicator into the can and spread evenly.
  3. Following the grain, lightly drag the applicator or brush from one end of the project to the other to remove applicator marks. Hold the applicator or brush with light pressure and maintain a wet edge.
  4. Wipe off any drips with a clean rag if necessary.

Clean Up and Disposal

Clean application tools immediately with regular mineral spirits1 or paint thinner. Do not pour extra product down the drain! Allow rags that are wet with product to dry in a well-ventilated area before disposal. Properly dispose of rags, applicators and waste. DANGER! Rags, steel wool or waste soaked with Waterlox may spontaneously catch fire if improperly discarded. Immediately after use, place rags, steel wool or waste in a sealed water-filled metal container. Read carefully other cautions on the product label.


  • Visit waterlox.com/storage. Keep container closed when not in use. Read carefully and follow all label instructions, guidelines, warnings and cautions.

Drying and Ventilation

  • Waterlox MARINE Sealer will dry through exposure to oxygen (oxidation).
  • Dry time before recoating is 24 hours.
  • Poor ventilation, high humidity or cool temperatures may increase dry times.
  • Read carefully other directions and cautions on the product label.
  • For full ventilation details, visit Drying, Ventilation, Curing and Circulation.

Waterlox MARINE Sealer is not a stand-alone product and will not provide a waterproof surface when used on its own. It is recommended to apply two coats of a Waterlox MARINE Finish overtop to fully waterproof and protect from UV/direct sunlight. For exterior, sun exposed projects, use the MARINE finishes.

SANDING IS NOT REQUIRED PRIOR TO YOUR FIRST COAT OF FINISH. The wood is sealed and ready for the first coat of finish. Lightly dampen a rag with mineral spirits or paint thinner1 or use a microfiber mop or rag and wipe the surface to pick up any stubborn sanding dust.

This guide is intended to be a standard application procedure. See the MARINE product page for additional guides and tips.


DANGER! COMBUSTIBLE LIQUID AND VAPOR CONTAINS MINERAL SPIRITS. VAPOR HARMFUL. MAY AFFECT THE BRAIN OR NERVOUS SYSTEM CAUSING DIZZINESS, HEADACHE OR NAUSEA. CAUSES EYE, SKIN, NOSE AND THROAT IRRITATION. NOTICE: Reports have associated repeated and prolonged occupational overexposure to solvents with permanent brain and nervous system damage. Intentional misuse by deliberately concentrating and inhaling the contents may be harmful or fatal. Keep away from heat and flame. Prevent build-up of vapors by opening all windows and doors to achieve cross-ventilation. Use only with adequate ventilation. Do not breathe vapors or spray mist. Ensure fresh air entry during application and drying. If you experience eye watering, headache or dizziness or if air monitoring demonstrates vapor/mist levels are above applicable limits, wear an appropriate, properly fitted respirator (NIOSH/MSHA approved) during and after application. Follow respirator manufacturer’s directions for respirator use. Close container after each use. Avoid contact with eyes, skin and clothing. Wash thoroughly after handling. FIRST AID: In case of eye contact, flush immediately with plenty of water for at least 15 minutes and get medical attention; for skin, wash thoroughly with soap and water. If you experience difficulty in breathing, leave the area to obtain fresh air. If continued difficulty is experienced, get medical assistance immediately. If swallowed, do not induce vomiting. Call physician immediately. If spilled, contain spilled material and remove with inert absorbent. Dispose of contaminated absorbent, container and unused contents in accordance with local, state and federal regulations.

WARNING! Cancer and Reproductive Harm – www.P65Warnings.ca.gov

WARNING: If you scrape, sand or remove old paint, you may release lead dust. Lead is toxic. Exposure to lead dust can cause serious illness, such as brain damage, especially in children. Pregnant women should also avoid exposure. Wear a NIOSH-approved respirator to control lead exposure. Clean up carefully with a HEPA vacuum and a wet mop. Before you start, find out how to protect yourself and your family by contacting the National Lead Information Hotline at 1-800-424-LEAD or log onto www.epa.gov/lead.



1 If regular mineral spirits or paint thinner is not available in your area, there are alternatives. Visit waterlox.com/mineralspirits.