Waterlox UTOS Application Guide

UNIVERSAL Tung Oil Sealer (UTOS) is a low VOC, low odor buff-in sealer that works as a base/sealer coat for Waterlox ORIGINAL, H2OLOX®, MARINE and URETHANE finishes. It is the same Tung Oil and resin composition as our ORIGINAL formula, delivered in a way to eliminate solvents while still providing the same depth and richness to wood surfaces. For more information, see the advantages of the UNIVERSAL Tung Oil Sealer guide.

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 spirits1.
  • Painter’s tape.
  • Box fan(s) to insure cross-ventilation.


For Large Projects:

  • Use one of the following applicators when applying UTOS:
    • Thick, non-abrasive buffing pad (white 3M® 4100 woven pad is recommended) on a low speed rotary floor buffer. One for every 500′ ft. of flooring is recommended.
    • Flexible trowel specifically for applying coatings to wood (corners should be rounded and it should have good flexibility).
  • The round center hole insert of the woven pad or similar small paint pad (see the small project section for other options) for cutting in edges.
  • Additional clean buffing pads or clean towels for removing excess finish.

For Small Projects:

  • Use one of the following applicators when applying UTOS:
    • Buffing pad/cloth – soft non-abrasive pad that will not fall apart when rubbing the wood surface. Examples: clean rags, sponge wrapped in an old t-shirt, car buffing pad or woven fiber polishing/buffing pad (be sure it does not contain a previous product or additives).
    • Flexible trowel specifically for applying coatings to wood (corners should be rounded and it should have some good flexibility).
  • Clean, lint-free rags, old t-shirt or towel(s) for removing the excess UTOS.
Surface Preparation
  • 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 100-120 grit; (150-grit max). As with any penetrating oil, UTOS will highlight sanding mistakes and imperfections.
  • 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 UTOS.1
  • Tape off or cover any surfaces not being coated.
Application and Product Handling

Application Process

  • Pour a small puddle of UTOS onto the wood surface.
  • Buff, rub or trowel (drive in) UTOS using the chosen applicator into the wood. Do NOT brush or wipe; be sure to RUB INTO THE WOOD. A lot of speed or pressure is NOT needed; just rub the product (drive) into the wood surface.
    • On large projects, cut in edges with a hand pad or the center insert of the buffing pad. Do NOT work too far ahead (more than 10 minutes) of the buffer or trowel.
  • When the pad/applicator becomes dry (more difficult to spread the product), pour more finish onto the wood and continue.
  • Moving section to section, continue to rub (drive in) the finish into the wood until the whole area is coated.
  • MOST IMPORTANT STEP: When the surface is fully coated and saturated OR it has been 10 – 15 minutes (whichever is longer), begin buffing or rubbing off all excess material with a clean pad, rag or towel.
  • During application, remove any and all shiny spots (e.g.: puddles, spits, drips and bleed back) from the surface.
  • Do not let the excess sit on the surface for more than 30 minutes! Wipe off excess.
  • Once all excess UTOS is removed, allow to dry overnight. Cross-ventilation is recommended. Properly dispose of all oil-soaked applicators to prevent any chance of spontaneous combustion. Read and follow all label instructions, guidelines and cautions.
  • A SPECIAL NOTE ABOUT HIGH TANIN and OILY/EXOTIC WOODS: For woods that have high tannin content (i.e. white and red oak, walnut, cherry) and oily/exotic woods (i.e. IPE, cocobolo, teak, rosewood, mahogany etc.) a second coat of UTOS is required as described above and before moving on to the finish. This will block the tannins and absorb the wood oils.
  • A SPECIAL NOTE ABOUT SOFTER WOODS: For woods that are softer than oak (i.e. pine, fir, cherry, walnut, etc.) a second coat of UTOS is recommended as described above and before moving on to the finish. This will provide an adequate film build.

Clean Up

Clean application tools immediately with soapy water. 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, applicators, steel wool or waste soaked with Waterlox may spontaneously catch fire if improperly discarded. Immediately after use, place in a sealed water-filled metal container. Read carefully other cautions on the product label.

Storage and Disposal

Visit waterlox.com/storage. Keep from freezing. Keep container closed when not in use. Read carefully other cautions on the product label.


UTOS 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 finish overtop UTOS to fully waterproof the surface. For interior projects, use the ORIGINAL, H2OLOX® or URETHANE finishes. For exterior, sun exposed projects, use the MARINE finishes. You can also use the Find Your Finishing System tool under “How-To” to select finishes.

DO NOT SAND BEFORE APPLYING YOUR FIRST COAT OF FINISH. The wood is sealed and due to the buffing process, should be smooth and ready for the first coat. Lightly dampen a rag with mineral spirits, paint thinner or water and wipe the surface to pick up any stubborn sanding dust.


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.